Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer...

Transport Layer 3-1

Chapter 3Transport Layer

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Thanks and enjoy JFKKWR

Computer Networking A Top Down Approach Featuring the Internet 3rd edition Jim Kurose Keith RossAddison-Wesley July 2004

Transport Layer 3-2

Chapter 3 Transport LayerOur goals

understand principles behind transport layer services

multiplexingdemultiplexingreliable data transferflow controlcongestion control

learn about transport layer protocols in the Internet

UDP connectionless transportTCP connection-oriented transportTCP congestion control

Transport Layer 3-3

Chapter 3 outline

31 Transport-layer services32 Multiplexing and demultiplexing33 Connectionless transport UDP34 Principles of reliable data transfer

35 Connection-oriented transport TCP

segment structurereliable data transferflow controlconnection management

36 Principles of congestion control37 TCP congestion control

Transport Layer 3-4

Transport services and protocolsprovide logical communicationbetween app processes running on different hoststransport protocols run in end systems

send side breaks app messages into segments passes to network layerrcv side reassembles segments into messages passes to app layer

more than one transport protocol available to apps

Internet TCP and UDP

applicationtransportnetworkdata linkphysical

networkdata linkphysical

networkdata linkphysicalnetwork

data linkphysical

logical end-end transport

Transport Layer 3-5

Transport vs network layerHousehold analogy12 kids sending letters

to 12 kidsprocesses = kidsapp messages = letters in envelopeshosts = housestransport protocol = Ann and Billnetwork-layer protocol = postal service

network layer logical communication between hoststransport layer logical communication between processes

relies on enhances network layer services

Transport Layer 3-6

Internet transport-layer protocols

reliable in-order delivery (TCP)

congestion control flow controlconnection setup

unreliable unordered delivery UDP

no-frills extension of ldquobest-effortrdquo IP

services not available delay guaranteesbandwidth guarantees

data linkphysical

Transport Layer 3-7

Chapter 3 outline

Transport Layer 3-8

Multiplexingdemultiplexinggathering data from multiplesockets enveloping data with header (later used for demultiplexing)

Multiplexing at send host

delivering received segmentsto correct socket

Demultiplexing at rcv host

= socket = process

application

transport

network

link

physical

P1 application

transport

network

link

physical

application

transport

network

link

physical

P2P3 P4P1

host 1 host 2 host 3

Transport Layer 3-9

How demultiplexing workshost receives IP datagrams

each datagram has source IP address destination IP addresseach datagram carries 1 transport-layer segmenteach segment has source destination port number (recall well-known port numbers for specific applications)

host uses IP addresses amp port numbers to direct segment to appropriate socket

32 bits

source port dest port

applicationdata

(message)

other header fields

TCPUDP segment format

Transport Layer 3-10

Connectionless demultiplexingWhen host receives UDP segment

checks destination port number in segmentdirects UDP segment to socket with that port number

IP datagrams with different source IP addresses andor source port numbers directed to same socket

Create sockets with port numbers

DatagramSocket mySocket1 = new DatagramSocket(99111)

UDP socket identified by two-tuple

(dest IP address dest port number)

Connectionless demux (cont)DatagramSocket serverSocket = new DatagramSocket(6428)

ClientIPB

P2

clientIP A

P1P1P3

serverIP C

SP 6428DP 9157

SP 9157DP 6428

SP 6428DP 5775

SP 5775DP 6428

SP provides ldquoreturn addressrdquo

Connection-oriented demux

TCP socket identified by 4-tuple

source IP addresssource port numberdest IP addressdest port number

recv host uses all four values to direct segment to appropriate socket

Server host may support many simultaneous TCP sockets

each socket identified by its own 4-tuple

Web servers have different sockets for each connecting client

non-persistent HTTP will have different socket for each request

Connection-oriented demux(cont)

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4 P5 P6

D-IPC

SP 9157DP 80 server

IP CS-IP AD-IPCD-IPC

Connection-oriented demux Threaded Web Server

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4

D-IPC

SP 9157DP 80 server

Chapter 3 outline

UDP User Datagram Protocol [RFC 768]

ldquono frillsrdquo ldquobare bonesrdquo Internet transport protocolldquobest effortrdquo service UDP segments may be

lostdelivered out of order to app

connectionlessno handshaking between UDP sender receivereach UDP segment handled independently of others

Why is there a UDPno connection establishment (which can add delay)simple no connection state at sender receiversmall segment headerno congestion control UDP can blast away as fast as desired

UDP moreoften used for streaming multimedia apps

loss tolerantrate sensitive

other UDP usesDNSSNMP

reliable transfer over UDP add reliability at application layer

application-specific error recovery

32 bits

Applicationdata

(message)

length checksumLength in

bytes of UDPsegmentincluding

header

UDP segment format

UDP checksumGoal detect ldquoerrorsrdquo (eg flipped bits) in transmitted

segment

Receivercompute checksum of received segmentcheck if computed checksum equals checksum field value

NO - error detectedYES - no error detected But maybe errors nonetheless More later hellip

Sendertreat segment contents as sequence of 16-bit integerschecksum addition (1rsquos complement sum) of segment contentssender puts checksum value into UDP checksum field

Internet Checksum ExampleNote

When adding numbers a carryout from the most significant bit needs to be added to the result

Example add two 16-bit integers

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

Principles of Reliable data transferimportant in app transport link layerstop-10 list of important networking topics

characteristics of unreliable channel will determine complexity of reliable data transfer protocol (rdt)

Reliable data transfer getting started

sendside

receiveside

rdt_send() called from above (eg by app) Passed data to

deliver to receiver upper layer

udt_send() called by rdtto transfer packet over

unreliable channel to receiver

rdt_rcv() called when packet arrives on rcv-side of channel

deliver_data() called by rdt to deliver data to upper

Reliable data transfer getting startedWersquoll

incrementally develop sender receiver sides of reliable data transfer protocol (rdt)consider only unidirectional data transfer

but control info will flow on both directionsuse finite state machines (FSM) to specify sender receiver

state1

state2

event causing state transitionactions taken on state transition

state when in this ldquostaterdquo next state

uniquely determined by next event

eventactions

Rdt10 reliable transfer over a reliable channel

underlying channel perfectly reliableno bit errorsno loss of packets

separate FSMs for sender receiversender sends data into underlying channelreceiver read data from underlying channel

extract (packetdata)deliver_data(data)

Wait for call from

below

rdt_rcv(packet)Wait for call from above packet = make_pkt(data)

udt_send(packet)

rdt_send(data)

sender receiver

Rdt20 channel with bit errors

underlying channel may flip bits in packetchecksum to detect bit errors

the question how to recover from errorsacknowledgements (ACKs) receiver explicitly tells sender that pkt received OKnegative acknowledgements (NAKs) receiver explicitly tells sender that pkt had errorssender retransmits pkt on receipt of NAK

new mechanisms in rdt20 (beyond rdt10)error detectionreceiver feedback control msgs (ACKNAK) rcvr-gtsender

rdt20 FSM specification

Wait for call from above

snkpkt = make_pkt(data checksum)udt_send(sndpkt)

udt_send(sndpkt)

rdt_rcv(rcvpkt) ampampisNAK(rcvpkt)Wait for

ACK or NAK

rdt_send(data)

receiver

extract(rcvpktdata)deliver_data(data)udt_send(ACK)

rdt_rcv(rcvpkt) ampamp notcorrupt(rcvpkt)

udt_send(NAK)

rdt_rcv(rcvpkt) ampamp corrupt(rcvpkt)

Wait for call from

below

rdt_rcv(rcvpkt) ampamp isACK(rcvpkt)Λ

sender

rdt20 operation with no errors

rdt_rcv(rcvpkt) ampamp isACK(rcvpkt)

udt_send(sndpkt)

rdt_rcv(rcvpkt) ampampisNAK(rcvpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

rdt20 error scenario

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

rdt20 has a fatal flaw

What happens if ACKNAK corruptedsender doesnrsquot know what happened at receivercanrsquot just retransmit possible duplicate

Handling duplicates sender adds sequence number to each pktsender retransmits current pkt if ACKNAK garbledreceiver discards (doesnrsquot deliver up) duplicate pkt

Sender sends one packet then waits for receiver response

stop and wait

rdt21 sender handles garbled ACKNAKsrdt_send(data)

Wait for call 0 from

above

sndpkt = make_pkt(0 data checksum)udt_send(sndpkt)

Wait for ACK or NAK 0 udt_send(sndpkt)

rdt_rcv(rcvpkt) ampamp ( corrupt(rcvpkt) ||isNAK(rcvpkt) )

rdt_rcv(rcvpkt) ampamp notcorrupt(rcvpkt) ampamp isACK(rcvpkt)

Wait forcall 1 from

above

Wait for ACK or NAK 1

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 receiver handles garbled ACKNAKsrdt_rcv(rcvpkt) ampamp notcorrupt(rcvpkt)

ampamp has_seq0(rcvpkt)

Wait for 0 from below

sndpkt = make_pkt(NAK chksum)udt_send(sndpkt)

rdt_rcv(rcvpkt) ampamp not corrupt(rcvpkt) ampamphas_seq0(rcvpkt)

rdt_rcv(rcvpkt) ampamp notcorrupt(rcvpkt) ampamp has_seq1(rcvpkt)

extract(rcvpktdata)deliver_data(data)sndpkt = make_pkt(ACK chksum)udt_send(sndpkt)

rdt_rcv(rcvpkt) ampamp (corrupt(rcvpkt)

sndpkt = make_pkt(ACK chksum)udt_send(sndpkt)

rdt21 discussion

Senderseq added to pkttwo seq rsquos (01) will suffice Whymust check if received ACKNAK corrupted twice as many states

state must ldquorememberrdquo whether ldquocurrentrdquo pkt has 0 or 1 seq

Receivermust check if received packet is duplicate

state indicates whether 0 or 1 is expected pkt seq

note receiver can notknow if its last ACKNAK received OK at sender

rdt22 a NAK-free protocol

same functionality as rdt21 using ACKs onlyinstead of NAK receiver sends ACK for last pkt received OK

receiver must explicitly include seq of pkt being ACKed duplicate ACK at sender results in same action as NAK retransmit current pkt

rdt22 sender receiver fragments

above

rdt_send(data)

udt_send(sndpkt)

rdt_rcv(rcvpkt) ampamp ( corrupt(rcvpkt) ||

isACK(rcvpkt1) )

rdt_rcv(rcvpkt) ampamp notcorrupt(rcvpkt) ampamp isACK(rcvpkt0)

Wait for ACK

0sender FSM

fragment

rdt_rcv(rcvpkt) ampamp (corrupt(rcvpkt) ||

has_seq1(rcvpkt))

udt_send(sndpkt)receiver FSM

fragment

Λ

extract(rcvpktdata)deliver_data(data)sndpkt = make_pkt(ACK1 chksum)udt_send(sndpkt)

rdt30 channels with errors and loss

New assumptionunderlying channel can also lose packets (data or ACKs)

checksum seq ACKs retransmissions will be of help but not enough

Approach sender waits ldquoreasonablerdquo amount of time for ACK retransmits if no ACK received in this timeif pkt (or ACK) just delayed (not lost)

retransmission will be duplicate but use of seq rsquos already handles thisreceiver must specify seq of pkt being ACKed

requires countdown timer

rdt30 sendersndpkt = make_pkt(0 data checksum)udt_send(sndpkt)start_timer

Wait for

ACK0

rdt_rcv(rcvpkt) ampamp ( corrupt(rcvpkt) ||isACK(rcvpkt1) )

above

sndpkt = make_pkt(1 data checksum)udt_send(sndpkt)start_timer

rdt_send(data)rdt_rcv(rcvpkt) ampamp ( corrupt(rcvpkt) ||isACK(rcvpkt0) )

stop_timerstop_timer

udt_send(sndpkt)start_timer

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

Performance of rdt30

rdt30 works but performance stinksexample 1 Gbps link 15 ms e-e prop delay 1KB packet

L (packet length in bits) 8kbpkt109 bsec

Ttransmit = = = 8 microsecR (transmission rate bps)

U sender =

008 30008

= 000027 L R RTT + L R

=

U sender utilization ndash fraction of time sender busy sending1KB pkt every 30 msec -gt 33kBsec thruput over 1 Gbps linknetwork protocol limits use of physical resources

rdt30 stop-and-wait operation

RTT

last packet bit transmitted t = L R

ACK arrives send next packet t = RTT + L R

sender receiver

first packet bit transmitted t = 0

first packet bit arriveslast packet bit arrives send ACK

U sender =

00830008

= 000027 L R RTT + L R

=

Pipelined protocolsPipelining sender allows multiple ldquoin-flightrdquo yet-to-

be-acknowledged pktsrange of sequence numbers must be increasedbuffering at sender andor receiver

Two generic forms of pipelined protocols go-Back-N selective repeat

Pipelining increased utilization

RTT

last bit transmitted t = L R

last packet bit arrives send ACK

last bit of 2nd packet arrives send ACKlast bit of 3rd packet arrives send ACK

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

first packet bit arrives

Increase utilizationby a factor of 3

Go-Back-NSender

k-bit seq in pkt headerldquowindowrdquo of up to N consecutive unackrsquoed pkts allowed

ACK(n) ACKs all pkts up to including seq n - ldquocumulative ACKrdquomay deceive duplicate ACKs (see receiver)

timer for each in-flight pkttimeout(n) retransmit pkt n and all higher seq pkts in window

GBN sender extended FSMrdt_send(data)

Wait start_timerudt_send(sndpkt[base])udt_send(sndpkt[base+1])hellipudt_send(sndpkt[nextseqnum-1])

timeout

if (nextseqnum lt base+N) sndpkt[nextseqnum] = make_pkt(nextseqnumdatachksum)udt_send(sndpkt[nextseqnum])if (base == nextseqnum)

start_timernextseqnum++

elserefuse_data(data)

base=1nextseqnum=1

Λ

base = getacknum(rcvpkt)+1If (base == nextseqnum)

stop_timerelse

start_timer

GBN receiver extended FSM

Wait

default

rdt_rcv(rcvpkt)ampamp notcurrupt(rcvpkt)ampamp hasseqnum(rcvpktexpectedseqnum)

extract(rcvpktdata)deliver_data(data)sndpkt = make_pkt(expectedseqnumACKchksum)udt_send(sndpkt)expectedseqnum++

expectedseqnum=1sndpkt =

make_pkt(expectedseqnumACKchksum)

Λ

udt_send(sndpkt)

ACK-only always send ACK for correctly-received pktwith highest in-order seq

may generate duplicate ACKsneed only remember expectedseqnum

out-of-order pkt discard (donrsquot buffer) -gt no receiver bufferingRe-ACK pkt with highest in-order seq

GBN inaction

Selective Repeat

receiver individually acknowledges all correctly received pkts

buffers pkts as needed for eventual in-order delivery to upper layer

sender only resends pkts for which ACK not received

sender timer for each unACKed pktsender window

N consecutive seq rsquosagain limits seq s of sent unACKed pkts

Selective repeat sender receiver windows

Selective repeat

data from above if next available seq in window send pkt

timeout(n)resend pkt n restart timer

ACK(n) in [sendbasesendbase+N]

mark pkt n as receivedif n smallest unACKed pkt advance window base to next unACKed seq

senderpkt n in [rcvbase rcvbase+N-1]

send ACK(n)out-of-order bufferin-order deliver (also deliver buffered in-order pkts) advance window to next not-yet-received pkt

pkt n in [rcvbase-Nrcvbase-1]

ACK(n)otherwise

ignore

receiver

Selective repeat in action

Selective repeatdilemma

Example seq rsquos 0 1 2 3window size=3

receiver sees no difference in two scenariosincorrectly passes duplicate data as new in (a)

Q what relationship between seq size and window size

Chapter 3 outline

TCP Overview RFCs 793 1122 1323 2018 2581

full duplex databi-directional data flow in same connectionMSS maximum segment size

connection-orientedhandshaking (exchange of control msgs) initrsquossender receiver state before data exchange

flow controlledsender will not overwhelm receiver

point-to-pointone sender one receiver

reliable in-order byte steam

no ldquomessage boundariesrdquopipelined

TCP congestion and flow control set window size

send amp receive buffers

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

applicationwrites data

applicationreads data

TCP segment structure

32 bits

applicationdata

(variable length)

sequence numberacknowledgement number

Receive windowUrg data pnterchecksum

FSRPAUheadlen

notused

Options (variable length)

URG urgent data (generally not used)

ACK ACK valid

PSH push data now(generally not used)

RST SYN FINconnection estab(setup teardown

commands)

Internetchecksum

(as in UDP)

countingby bytes of data(not segments)

bytes rcvr willingto accept

TCP seq rsquos and ACKsSeq rsquos

byte stream ldquonumberrdquo of first byte in segmentrsquos data

ACKsseq of next byte expected from other sidecumulative ACK

Q how receiver handles out-of-order segments

A TCP spec doesnrsquot say - up to implementor

Host BHost A

Seq=43 ACK=80

=42 ACK=79 data = lsquoCrsquo

Seq

Seq=79 ACK=43 data = lsquoCrsquo

Usertypes

lsquoCrsquohost ACKsreceipt oflsquoCrsquo echoes

back lsquoCrsquo

host ACKsreceipt

of echoedlsquoCrsquo

timesimple telnet scenario

TCP Round Trip Time and Timeout

Q how to estimate RTTSampleRTT measured time from segment transmission until ACK receipt

ignore retransmissionsSampleRTT will vary want estimated RTT ldquosmootherrdquo

average several recent measurements not just current SampleRTT

Q how to set TCP timeout valuelonger than RTT

but RTT variestoo short premature timeout

unnecessary retransmissions

too long slow reaction to segment loss

EstimatedRTT = (1- α)EstimatedRTT + αSampleRTT

Exponential weighted moving averageinfluence of past sample decreases exponentially fasttypical value α = 0125

Example RTT estimationRTT gaiacsumassedu to fantasiaeurecomfr

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

SampleRTT Estimated RTT

TCP Round Trip Time and TimeoutSetting the timeout

EstimtedRTT plus ldquosafety marginrdquolarge variation in EstimatedRTT -gt larger safety margin

first estimate of how much SampleRTT deviates from EstimatedRTT

DevRTT = (1-β)DevRTT +β|SampleRTT-EstimatedRTT|

(typically β = 025)

Then set timeout interval

TimeoutInterval = EstimatedRTT + 4DevRTT

Chapter 3 outline

TCP reliable data transfer

TCP creates rdtservice on top of IPrsquos unreliable servicePipelined segmentsCumulative acksTCP uses single retransmission timer

Retransmissions are triggered by

timeout eventsduplicate acks

Initially consider simplified TCP sender

ignore duplicate acksignore flow control congestion control

TCP sender eventsdata rcvd from app

Create segment with seq seq is byte-stream number of first data byte in segmentstart timer if not already running (think of timer as for oldest unacked segment)expiration interval TimeOutInterval

timeoutretransmit segment that caused timeoutrestart timer

Ack rcvdIf acknowledges previously unackedsegments

update what is known to be ackedstart timer if there are outstanding segments

TCP sender(simplified)

NextSeqNum = InitialSeqNumSendBase = InitialSeqNum

loop (forever) switch(event)

event data received from application above create TCP segment with sequence number NextSeqNum if (timer currently not running)

start timerpass segment to IP NextSeqNum = NextSeqNum + length(data)

event timer timeoutretransmit not-yet-acknowledged segment with

smallest sequence numberstart timer

event ACK received with ACK field value of y if (y gt SendBase)

SendBase = yif (there are currently not-yet-acknowledged segments)

start timer

end of loop forever

Commentbull SendBase-1 last cumulatively ackrsquoed byteExamplebull SendBase-1 = 71y= 73 so the rcvrwants 73+ y gt SendBase sothat new data is acked

TCP retransmission scenariosHost A Host BHost A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

Seq=100 20 bytes data

ACK=100

timepremature timeout

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

TCP retransmission scenarios (more)Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Cumulative ACK scenario

Host B

X

ACK=120

time

SendBase= 120

TCP ACK generation [RFC 1122 RFC 2581]

Event at Receiver

Arrival of in-order segment withexpected seq All data up toexpected seq already ACKed

Arrival of in-order segment withexpected seq One other segment has ACK pending

Arrival of out-of-order segmenthigher-than-expect seq Gap detected

Arrival of segment that partially or completely fills gap

TCP Receiver action

Delayed ACK Wait up to 500msfor next segment If no next segmentsend ACK

Immediately send single cumulative ACK ACKing both in-order segments

Immediately send duplicate ACK indicating seq of next expected byte

Immediate send ACK provided thatsegment startsat lower end of gap

Fast Retransmit

Time-out period often relatively long

long delay before resending lost packet

Detect lost segments via duplicate ACKs

Sender often sends many segments back-to-backIf segment is lost there will likely be many duplicate ACKs

If sender receives 3 ACKs for the same data it supposes that segment after ACKeddata was lost

fast retransmit resend segment before timer expires

Fast retransmit algorithm

start timer

else increment count of dup ACKs received for yif (count of dup ACKs received for y = 3)

resend segment with sequence number y

a duplicate ACK for already ACKed segment

fast retransmit

Chapter 3 outline

TCP Flow Controlsender wonrsquot overflowreceiverrsquos buffer by

transmitting too muchtoo fast

flow controlreceive side of TCP connection has a receive buffer

speed-matching service matching the send rate to the receiving apprsquos drain rate

app process may be slow at reading from buffer

TCP Flow control how it works

(Suppose TCP receiver discards out-of-order segments)spare room in buffer

= RcvWindow= RcvBuffer-[LastByteRcvd -

LastByteRead]

Rcvr advertises spare room by including value of RcvWindow in segmentsSender limits unACKeddata to RcvWindow

guarantees receive buffer doesnrsquot overflow

Chapter 3 outline

TCP Connection ManagementThree way handshakeStep 1 client host sends TCP

SYN segment to serverspecifies initial seq no data

Step 2 server host receives SYN replies with SYNACK segment

server allocates buffersspecifies server initial seq

Step 3 client receives SYNACK replies with ACK segment which may contain data

Recall TCP sender receiver establish ldquoconnectionrdquo before exchanging data segmentsinitialize TCP variables

seq sbuffers flow control info (eg RcvWindow)

client connection initiatorSocket clientSocket = new Socket(hostnameport

number)

server contacted by clientSocket connectionSocket = welcomeSocketaccept()

TCP Connection Management (cont)

Closing a connection

client closes socketclientSocketclose()

Step 1 client end system sends TCP FIN control segment to server

Step 2 server receives FIN replies with ACK Closes connection sends FIN

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

Step 3 client receives FIN replies with ACK

Enters ldquotimed waitrdquo -will respond with ACK to received FINs

Step 4 server receives ACK Connection closed

Note with small modification can handle simultaneous FINs

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

Principles of Congestion Control

Congestioninformally ldquotoo many sources sending too much data too fast for network to handlerdquodifferent from flow controlmanifestations

lost packets (buffer overflow at routers)long delays (queueing in router buffers)

a top-10 problem

Causescosts of congestion scenario 1

unlimited shared output link buffers

Host Aλin original data

Host B

λouttwo senders two receiversone router infinite buffers no retransmission

large delays when congestedmaximum achievable throughput

one router finite buffers sender retransmission of lost packet

Host A λout

finite shared output link buffers

Host B

λin original data plus retransmitted data

λin original data

Causescosts of congestion scenario 2always (goodput)ldquoperfectrdquo retransmission only when loss

retransmission of delayed (not lost) packet makes larger(than perfect case) for same

λin

λout=

λin

λoutgtλ

inλout

ldquocostsrdquo of congestionmore work (retrans) for given ldquogoodputrdquounneeded retransmissions link carries multiple copies of pkt

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

Causescosts of congestion scenario 3four sendersmultihop pathstimeoutretransmit

λin

Q what happens as and increase λ

in

Host B

λout

Causescosts of congestion scenario 3Host A

Host B

λou

t

Another ldquocostrdquo of congestionwhen packet dropped any ldquoupstream transmission capacity used for that packet was wasted

Approaches towards congestion control

Two broad approaches towards congestion control

End-end congestion controlno explicit feedback from networkcongestion inferred from end-system observed loss delayapproach taken by TCP

Network-assisted congestion controlrouters provide feedback to end systems

single bit indicating congestion (SNA DECbit TCPIP ECN ATM)explicit rate sender should send at

Case study ATM ABR congestion control

ABR available bit rateldquoelastic servicerdquo if senderrsquos path ldquounderloadedrdquo

sender should use available bandwidth

if senderrsquos path congested

sender throttled to minimum guaranteed rate

RM (resource management) cellssent by sender interspersed with data cellsbits in RM cell set by switches (ldquonetwork-assistedrdquo)

NI bit no increase in rate (mild congestion)CI bit congestion indication

RM cells returned to sender by receiver with bits intact

two-byte ER (explicit rate) field in RM cellcongested switch may lower ER value in cellsenderrsquo send rate thus minimum supportable rate on path

EFCI bit in data cells set to 1 in congested switchif data cell preceding RM cell has EFCI set sender sets CI bit in returned RM cell

Chapter 3 outline

TCP Congestion Control

end-end control (no network assistance)sender limits transmissionLastByteSent-LastByteAcked

le CongWin

Roughly

CongWin is dynamic function of perceived network congestion

How does sender perceive congestionloss event = timeout or3 duplicate acksTCP sender reduces rate (CongWin) after loss event

three mechanismsAIMDslow startconservative after timeout events

rate = CongWinRTT Bytessec

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

additive increaseincrease CongWin by 1 MSS every RTT in the absence of loss events probing

multiplicative decreasecut CongWin in half after loss event

Long-lived TCP connection

TCP Slow Start

When connection begins CongWin = 1 MSS

Example MSS = 500 bytes amp RTT = 200 msecinitial rate = 20 kbps

available bandwidth may be gtgt MSSRTT

desirable to quickly ramp up to respectable rate

When connection begins increase rate exponentially fast until first loss event

TCP Slow Start (more)

When connection begins increase rate exponentially until first loss event

double CongWin every RTTdone by incrementing CongWin for every ACK received

Summary initial rate is slow but ramps up exponentially fast

Host A Host B

one segment

RTT

two segments

four segments

time

RefinementAfter 3 dup ACKs

CongWin is cut in halfwindow then grows linearly

But after timeout eventCongWin instead set to 1 MSS window then grows exponentiallyto a threshold then grows linearly

bull 3 dup ACKs indicates network capable of delivering some segmentsbull timeout before 3 dup ACKs is ldquomore alarmingrdquo

Philosophy

Refinement (more)Q When should the

exponential increase switch to linear

A When CongWingets to 12 of its value before timeout

ImplementationVariable Threshold At loss event Threshold is set to 12 of CongWin just before loss event

Summary TCP Congestion Control

When CongWin is below Threshold sender in slow-start phase window grows exponentially

When CongWin is above Threshold sender is in congestion-avoidance phase window grows linearly

When a triple duplicate ACK occurs Thresholdset to CongWin2 and CongWin set to Threshold

When timeout occurs Threshold set to CongWin2 and CongWin is set to 1 MSS

TCP sender congestion control

CongWin and Threshold not changed

Increment duplicate ACK count for segment being acked

SS or CADuplicate ACK

Enter slow startThreshold = CongWin2 CongWin = 1 MSSSet state to ldquoSlow Startrdquo

SS or CATimeout

Fast recovery implementing multiplicative decrease CongWin will not drop below 1 MSS

Threshold = CongWin2 CongWin = ThresholdSet state to ldquoCongestion Avoidancerdquo

SS or CALoss event detected by triple duplicate ACK

Additive increase resulting in increase of CongWin by 1 MSS every RTT

CongWin = CongWin+MSS (MSSCongWin)

CongestionAvoidance (CA)

ACK receipt for previously unackeddata

Resulting in a doubling of CongWin every RTT

CongWin = CongWin + MSS If (CongWin gt Threshold)

set state to ldquoCongestion Avoidancerdquo

Slow Start (SS)

CommentaryTCP Sender Action StateEvent

TCP throughput

Whatrsquos the average throughout ot TCP as a function of window size and RTT

Ignore slow startLet W be the window size when loss occursWhen window is W throughput is WRTTJust after loss window drops to W2 throughput to W2RTT Average throughout 75 WRTT

TCP Futures

Example 1500 byte segments 100ms RTT want 10 Gbps throughputRequires window size W = 83333 in-flight segmentsThroughput in terms of loss rate

L = 210-10 WowNew versions of TCP for high-speed needed

LRTTMSSsdot221

TCP FairnessFairness goal if K TCP sessions share same

bottleneck link of bandwidth R each should have average rate of RK

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

Why is TCP fairTwo competing sessions

Additive increase gives slope of 1 as throughout increasesmultiplicative decrease decreases throughput proportionally

ctio

n 2

t hro

congestion avoidance additive increaseloss decrease window by factor of 2

equal bandwidth share

Conn

eu g

hput

R

Connection 1 throughput R

Fairness (more)Fairness and UDP

Multimedia apps often do not use TCP

do not want rate throttled by congestion control

Instead use UDPpump audiovideo at constant rate tolerate packet loss

Research area TCP friendly

Fairness and parallel TCP connectionsnothing prevents app from opening parallel cnctionsbetween 2 hostsWeb browsers do this Example link of rate R supporting 9 cnctions

new app asks for 1 TCP gets rate R10new app asks for 11 TCPs gets R2

Delay modelingNotation assumptions

Assume one link between client and server of rate RS MSS (bits)O object size (bits)no retransmissions (no loss no corruption)

Window sizeFirst assume fixed congestion window W segmentsThen dynamic window

modeling slow start

Q How long does it take to receive an object from a Web server after sending a request

Ignoring congestion delay is influenced byTCP connection establishmentdata transmission delayslow start

Fixed congestion window (1)

First caseWSR gt RTT + SR ACK for

first segment in window returns before windowrsquos worth of data sent

delay = 2RTT + OR

Second caseWSR lt RTT + SR wait for ACK after sending windowrsquos worth of data sent

delay = 2RTT + OR+ (K-1)[SR + RTT - WSR]

TCP Delay Modeling Slow Start (1)

Now suppose window grows according to slow start

Will show that the delay for one object is

RS

RSRTTP

RORTTLatency P )12(2 minusminus

+++=

where P is the number of times TCP idles at server

1min minus= KQP

- where Q is the number of times the server idlesif the object were of infinite size

- and K is the number of windows that cover the object

RTT

initiate TCPconnection

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

completetransmissionobject

delivered

time atclient

time atserver

Examplebull OS = 15 segmentsbull K = 4 windowsbull Q = 2bull P = minK-1Q = 2

Server idles P=2 times

Delay componentsbull 2 RTT for connection estab and requestbull OR to transmit objectbull time server idles due to slow start

Server idles P = minK-1Q times

TCP Delay Modeling (3)

ementacknowledg receivesserver until

segment send tostartsserver whenfrom time=+ RTTRS

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

th window after the timeidle 2 1 kRSRTT

RS k =

minus+

+minus

window kth the transmit totime2 1 =minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

TCP Delay Modeling (4)Recall K = number of windows that cover object

How do we calculate K

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

Calculation of Q number of idles for infinite-size objectis similar (see HW)

HTTP ModelingAssume Web page consists of

1 base HTML page (of size O bits)M images (each of size O bits)

Non-persistent HTTP M+1 TCP connections in seriesResponse time = (M+1)OR + (M+1)2RTT + sum of idle times

Persistent HTTP2 RTT to request and receive base HTML file1 RTT to request and receive M imagesResponse time = (M+1)OR + 3RTT + sum of idle times

Non-persistent HTTP with X parallel connectionsSuppose MX integer1 TCP connection for base fileMX sets of parallel connections for imagesResponse time = (M+1)OR + (MX + 1)2RTT + sum of idle times

HTTP Response time (in seconds)RTT = 100 msec O = 5 Kbytes M=10 and X=5

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

parallel non-persistent

For low bandwidth connection amp response time dominated by transmission timePersistent connections only give minor improvement over parallelconnections

HTTP Response time (in seconds)

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

RTT =1 sec O = 5 Kbytes M=10 and X=5

For larger RTT response time dominated by TCP establishment amp slow start delays Persistent connections now give important improvement particularly in high delaybullbandwidth networks

Chapter 3 Summaryprinciples behind transport layer services

multiplexing demultiplexingreliable data transferflow controlcongestion control

instantiation and implementation in the Internet

UDPTCP

Nextleaving the network ldquoedgerdquo (application transport layers)into the network ldquocorerdquo

Chapter 3 Transport Layer
Chapter 3 outline
Transport services and protocols
Transport vs network layer
Chapter 3 outline
Multiplexingdemultiplexing
How demultiplexing works
Connectionless demultiplexing
Connectionless demux (cont)
Connection-oriented demux (cont)
Chapter 3 outline
UDP more
UDP checksum
Internet Checksum Example
Chapter 3 outline
Principles of Reliable data transfer
rdt21 sender handles garbled ACKNAKs
rdt21 receiver handles garbled ACKNAKs
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN sender extended FSM
GBN inaction
Selective Repeat
Selective repeat
Selective repeat dilemma
Chapter 3 outline
TCP seq rsquos and ACKs
Example RTT estimation
Chapter 3 outline
TCP sender events
TCP retransmission scenarios
TCP retransmission scenarios (more)
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
TCP Connection Management
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 2: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Transport Layer 3-2

Chapter 3 Transport LayerOur goals

understand principles behind transport layer services

multiplexingdemultiplexingreliable data transferflow controlcongestion control

learn about transport layer protocols in the Internet

UDP connectionless transportTCP connection-oriented transportTCP congestion control

Transport Layer 3-3

Chapter 3 outline

Transport Layer 3-4

data linkphysical

Transport Layer 3-5

Transport Layer 3-6

data linkphysical

Transport Layer 3-7

Chapter 3 outline

Transport Layer 3-8

= socket = process

application

transport

network

link

physical

P1 application

transport

network

link

physical

application

transport

network

link

physical

P2P3 P4P1

Transport Layer 3-9

32 bits

applicationdata

(message)

other header fields

ClientIPB

P2

clientIP A

P1P1P3

serverIP C

SP 6428DP 9157

SP 9157DP 6428

SP 6428DP 5775

SP 5775DP 6428

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4 P5 P6

D-IPC

SP 9157DP 80 server

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4

D-IPC

SP 9157DP 80 server

Chapter 3 outline

32 bits

Applicationdata

(message)

header

UDP segment format

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 3: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Transport Layer 3-3

Chapter 3 outline

Transport Layer 3-4

data linkphysical

Transport Layer 3-5

Transport Layer 3-6

data linkphysical

Transport Layer 3-7

Chapter 3 outline

Transport Layer 3-8

= socket = process

application

transport

network

link

physical

P1 application

transport

network

link

physical

application

transport

network

link

physical

P2P3 P4P1

Transport Layer 3-9

32 bits

applicationdata

(message)

other header fields

ClientIPB

P2

clientIP A

P1P1P3

serverIP C

SP 6428DP 9157

SP 9157DP 6428

SP 6428DP 5775

SP 5775DP 6428

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4 P5 P6

D-IPC

SP 9157DP 80 server

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4

D-IPC

SP 9157DP 80 server

Chapter 3 outline

32 bits

Applicationdata

(message)

header

UDP segment format

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 4: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Transport Layer 3-4

data linkphysical

Transport Layer 3-5

Transport Layer 3-6

data linkphysical

Transport Layer 3-7

Chapter 3 outline

Transport Layer 3-8

= socket = process

application

transport

network

link

physical

P1 application

transport

network

link

physical

application

transport

network

link

physical

P2P3 P4P1

Transport Layer 3-9

32 bits

applicationdata

(message)

other header fields

ClientIPB

P2

clientIP A

P1P1P3

serverIP C

SP 6428DP 9157

SP 9157DP 6428

SP 6428DP 5775

SP 5775DP 6428

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4 P5 P6

D-IPC

SP 9157DP 80 server

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4

D-IPC

SP 9157DP 80 server

Chapter 3 outline

32 bits

Applicationdata

(message)

header

UDP segment format

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 5: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Transport Layer 3-5

Transport Layer 3-6

data linkphysical

Transport Layer 3-7

Chapter 3 outline

Transport Layer 3-8

= socket = process

application

transport

network

link

physical

P1 application

transport

network

link

physical

application

transport

network

link

physical

P2P3 P4P1

Transport Layer 3-9

32 bits

applicationdata

(message)

other header fields

ClientIPB

P2

clientIP A

P1P1P3

serverIP C

SP 6428DP 9157

SP 9157DP 6428

SP 6428DP 5775

SP 5775DP 6428

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4 P5 P6

D-IPC

SP 9157DP 80 server

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4

D-IPC

SP 9157DP 80 server

Chapter 3 outline

32 bits

Applicationdata

(message)

header

UDP segment format

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 6: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Transport Layer 3-6

data linkphysical

Transport Layer 3-7

Chapter 3 outline

Transport Layer 3-8

= socket = process

application

transport

network

link

physical

P1 application

transport

network

link

physical

application

transport

network

link

physical

P2P3 P4P1

Transport Layer 3-9

32 bits

applicationdata

(message)

other header fields

ClientIPB

P2

clientIP A

P1P1P3

serverIP C

SP 6428DP 9157

SP 9157DP 6428

SP 6428DP 5775

SP 5775DP 6428

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4 P5 P6

D-IPC

SP 9157DP 80 server

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4

D-IPC

SP 9157DP 80 server

Chapter 3 outline

32 bits

Applicationdata

(message)

header

UDP segment format

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 7: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Transport Layer 3-7

Chapter 3 outline

Transport Layer 3-8

= socket = process

application

transport

network

link

physical

P1 application

transport

network

link

physical

application

transport

network

link

physical

P2P3 P4P1

Transport Layer 3-9

32 bits

applicationdata

(message)

other header fields

ClientIPB

P2

clientIP A

P1P1P3

serverIP C

SP 6428DP 9157

SP 9157DP 6428

SP 6428DP 5775

SP 5775DP 6428

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4 P5 P6

D-IPC

SP 9157DP 80 server

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4

D-IPC

SP 9157DP 80 server

Chapter 3 outline

32 bits

Applicationdata

(message)

header

UDP segment format

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 8: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Transport Layer 3-8

= socket = process

application

transport

network

link

physical

P1 application

transport

network

link

physical

application

transport

network

link

physical

P2P3 P4P1

Transport Layer 3-9

32 bits

applicationdata

(message)

other header fields

ClientIPB

P2

clientIP A

P1P1P3

serverIP C

SP 6428DP 9157

SP 9157DP 6428

SP 6428DP 5775

SP 5775DP 6428

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4 P5 P6

D-IPC

SP 9157DP 80 server

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4

D-IPC

SP 9157DP 80 server

Chapter 3 outline

32 bits

Applicationdata

(message)

header

UDP segment format

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 9: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Transport Layer 3-9

32 bits

applicationdata

(message)

other header fields

ClientIPB

P2

clientIP A

P1P1P3

serverIP C

SP 6428DP 9157

SP 9157DP 6428

SP 6428DP 5775

SP 5775DP 6428

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4 P5 P6

D-IPC

SP 9157DP 80 server

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4

D-IPC

SP 9157DP 80 server

Chapter 3 outline

32 bits

Applicationdata

(message)

header

UDP segment format

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 10: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

ClientIPB

P2

clientIP A

P1P1P3

serverIP C

SP 6428DP 9157

SP 9157DP 6428

SP 6428DP 5775

SP 5775DP 6428

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4 P5 P6

D-IPC

SP 9157DP 80 server

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4

D-IPC

SP 9157DP 80 server

Chapter 3 outline

32 bits

Applicationdata

(message)

header

UDP segment format

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 11: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

ClientIPB

P2

clientIP A

P1P1P3

serverIP C

SP 6428DP 9157

SP 9157DP 6428

SP 6428DP 5775

SP 5775DP 6428

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4 P5 P6

D-IPC

SP 9157DP 80 server

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4

D-IPC

SP 9157DP 80 server

Chapter 3 outline

32 bits

Applicationdata

(message)

header

UDP segment format

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 12: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4 P5 P6

D-IPC

SP 9157DP 80 server

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4

D-IPC

SP 9157DP 80 server

Chapter 3 outline

32 bits

Applicationdata

(message)

header

UDP segment format

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 13: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4 P5 P6

D-IPC

SP 9157DP 80 server

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4

D-IPC

SP 9157DP 80 server

Chapter 3 outline

32 bits

Applicationdata

(message)

header

UDP segment format

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 14: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

P1

clientIP A

ClientIPB

P1P2

SP 9157DP 80

P3

S-IP B

SP 5775DP 80S-IP B

P4

D-IPC

SP 9157DP 80 server

Chapter 3 outline

32 bits

Applicationdata

(message)

header

UDP segment format

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 15: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Chapter 3 outline

32 bits

Applicationdata

(message)

header

UDP segment format

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 16: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

32 bits

Applicationdata

(message)

header

UDP segment format

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 17: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

32 bits

Applicationdata

(message)

header

UDP segment format

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 18: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

segment

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 19: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 01 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 0 1 1

1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 01 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1

wraparound

sumchecksum

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 20: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Chapter 3 outline

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 21: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 22: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

sendside

receiveside

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 23: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

state1

state2

eventactions

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 24: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Wait for call from

below

udt_send(packet)

rdt_send(data)

sender receiver

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 25: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 26: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

udt_send(sndpkt)

ACK or NAK

rdt_send(data)

receiver

udt_send(NAK)

Wait for call from

below

sender

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 27: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 28: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

udt_send(sndpkt)

udt_send(NAK)

Wait for ACK or

NAK

Wait for call from

below

rdt_send(data)

Λ

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 29: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

stop and wait

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 30: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

above

Wait forcall 1 from

above

Λ

rdt_send(data)

udt_send(sndpkt)

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 31: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 32: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

rdt21 discussion

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 33: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 34: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

above

rdt_send(data)

udt_send(sndpkt)

isACK(rcvpkt1) )

Wait for ACK

0sender FSM

fragment

has_seq1(rcvpkt))

fragment

Λ

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 35: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 36: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Wait for

ACK0

above

timeout

rdt_rcv(rcvpkt)

Wait for call 0from

above

Wait for

ACK1

Λrdt_rcv(rcvpkt)

ΛΛ

rdt_send(data)

Λ

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 37: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 38: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

rdt30 in action

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 39: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

U sender =

008 30008

= 000027 L R RTT + L R

=

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 40: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

RTT

sender receiver

U sender =

00830008

= 000027 L R RTT + L R

=

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 41: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 42: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

RTT

U sender =

024 30008

= 00008 3 L R RTT + L R

=

sender receiver

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 43: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Go-Back-NSender

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 44: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

timeout

base=1nextseqnum=1

Λ

stop_timerelse

start_timer

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 45: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Wait

default

Λ

udt_send(sndpkt)

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 46: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

GBN inaction

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 47: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Selective Repeat

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 48: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 49: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Selective repeat

ACK(n)otherwise

ignore

receiver

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 50: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 51: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 52: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Chapter 3 outline

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 53: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

socketdoor

TCPsend buffer

TCPreceive buffer

socketdoor

segment

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 54: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

32 bits

applicationdata

(variable length)

FSRPAUheadlen

notused

ACK ACK valid

commands)

Internetchecksum

(as in UDP)

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 55: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Host BHost A

Seq=43 ACK=80

Seq

Usertypes

back lsquoCrsquo

host ACKsreceipt

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 56: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 57: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 58: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

iseco

nds)

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 59: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 60: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Chapter 3 outline

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 61: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 62: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 63: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

start timer

end of loop forever

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 64: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

SendBase= 100

ACK=100

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92 t

imeo

ut

ACK=120

Seq=

92 t

imeo

ut

SendBase= 120

Sendbase= 100

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 65: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Host B

X

ACK=120

time

SendBase= 120

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 66: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Event at Receiver

TCP Receiver action

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 67: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Fast Retransmit

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 68: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

start timer

fast retransmit

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 69: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Chapter 3 outline

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 70: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 71: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

LastByteRead]

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 72: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Chapter 3 outline

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 73: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

number)

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 74: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 75: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

client server

FIN

ACK

tim

ed w

ait

closing

ACK

FINclosing

closed

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 76: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

TCP serverlifecycle

TCP clientlifecycle

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 77: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Chapter 3 outline

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 78: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

a top-10 problem

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 79: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Host B

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 80: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Host A λout

Host B

λin original data

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 81: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

λin

λout=

λin

λoutgtλ

inλout

R2

R2λin

λ out

b

R2

R2λin

λ out

a

R2

R2λin

λ out

c

R4

R3

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 82: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

λin

in

Host B

λout

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 83: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Host B

λou

t

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 84: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 85: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 86: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 87: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Chapter 3 outline

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 88: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

le CongWin

Roughly

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 89: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 90: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

TCP Slow Start

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 91: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Host A Host B

one segment

RTT

two segments

four segments

time

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 92: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

Philosophy

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 93: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 94: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 95: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

SS or CATimeout

Slow Start (SS)

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 96: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

TCP throughput

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 97: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

TCP Futures

LRTTMSSsdot221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 98: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 99: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

ctio

n 2

t hro

Conn

eu g

hput

R

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 100: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 101: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

modeling slow start

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 102: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

delay = 2RTT + OR

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 103: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 104: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

RS

RSRTTP

+++=

1min minus= KQP

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 105: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 106: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

RS

RSRTTPRTT

RO

RSRTT

RO

idleTimeRTTRO

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

minusminus+++=

minus+++=

++=

minus

=

sum

RS k =

minus+

+minus

RSk

RTT

requestobject

first window= SR

second window= 2SR

third window= 4SR

fourth window= 8SR

delivered

time atclient

time atserver

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 107: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

+=

+ge=

geminus=

ge+++=

ge+++=minus

minus

)1(log

)1(logmin

12min

222min222min

2

110

SO

SOkk

SOk

SOkOSSSkK

k

L

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 108: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 109: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

02468

101214161820

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

0

10

20

30

40

50

60

70

28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 110: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

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28Kbps

100Kbps

1Mbps

10Mbps

non-persistent

persistent

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

Page 111: Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer 3-1 Chapter 3 Transport Layer A note on the use of these ppt slides: We’re making

UDPTCP

Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
UDP more
UDP checksum
Chapter 3 outline
rdt21 discussion
rdt30 sender
rdt30 in action
rdt30 in action
Pipelined protocols
Go-Back-N
GBN inaction
Selective Repeat
Selective repeat
Chapter 3 outline
Chapter 3 outline
TCP sender events
Fast Retransmit
Chapter 3 outline
TCP Flow Control
Chapter 3 outline
Chapter 3 outline
Chapter 3 outline
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Delay modeling
HTTP Modeling
Chapter 3 Summary

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Chapter 3 Transport Layermario/paginas/3rdEditionChapter3.pdf · 2007. 11. 15. · Transport Layer...

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