Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th....

Transport Layer 3-1

AnnouncementHomework 2 in tonight

Will be graded and sent back before Th class

Midterm next Tu in classReview session next timeClosed bookOne 85rdquo by 11rdquo sheet of paper permitted

Recitation tomorrow on project 2

Transport Layer 3-2

Review of Previous Lecture

Connection-oriented transport TCP Overview and segment structure

bull RTT and RTO Reliable data transfer

bull Timeout and fast retransmit Flow control

bull Donrsquot overwhelm the receiver Connection management

Transport Layer 3-3

TCP Connection Management

Closing a connectionThree way handshake

Step 1 client host sends TCP SYN segment to server specifies initial seq no data

Step 2 server host receives SYN replies with SYNACK segment server allocates buffers specifies server initial

seq Step 3 client receives SYNACK

replies with ACK segment which may contain data

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

Transport Layer 3-4

Outline

Principles of congestion control TCP congestion control

Transport Layer 3-5

Principles of Congestion Control

Congestion informally ldquotoo many sources sending too

much data too fast for network to handlerdquo different from flow control manifestations

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

a top-10 problem

Transport Layer 3-6

Causescosts of congestion scenario 1

two senders two receivers

one router infinite buffers

no retransmission

large delays when congested

maximum achievable throughput

unlimited shared output link buffers

Host Ain original data

Host B

out

Transport Layer 3-7

one router finite buffers sender retransmission of lost packet

finite shared output link buffers

Host A in original data

Host B

out

in original data plus retransmitted data

Transport Layer 3-8

Causescosts of congestion scenario 2 always (goodput)

ldquoperfectrdquo retransmission only when loss

retransmission of delayed (not lost) packet makes

larger (than perfect case) for same

in

out

=

in

out

gt

in

out

ldquocostsrdquo of congestion more work (retrans) for given ldquogoodputrdquo unneeded retransmissions link carries multiple copies of pkt

R2

R2in

ou

t

b

R2

R2in

ou

t

a

R2

R2in

ou

t

c

R4

R3

Transport Layer 3-9

Causescosts of congestion scenario 3 four senders multihop paths timeoutretransmit

in

Q what happens as and increase

in

Host B

out

Transport Layer 3-10

Another ldquocostrdquo of congestion when packet dropped any ldquoupstream transmission capacity

used for that packet was wasted

Host A

Host B

o

u

t

Approaches towards congestion control

End-end congestion control

no explicit feedback from network

congestion inferred from end-system observed loss delay

approach taken by TCP

Network-assisted congestion control

routers provide feedback to end systems single bit indicating

congestion (SNA DECbit TCPIP ECN ATM)

explicit rate sender should send at

Two broad approaches towards congestion control

Case study ATM ABR congestion control

ABR available bit rate

ldquoelastic servicerdquo if senderrsquos path

ldquounderloadedrdquo sender should use

available bandwidth if senderrsquos path

congested sender throttled to

minimum guaranteed rate

RM (resource management) cells

sent by sender interspersed with data cells

bits in RM cell set by switches (ldquonetwork-assistedrdquo)

Implicit control 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 cell congested switch may lower ER value in cell senderrsquo send rate thus minimum supportable rate on

path

Scalability issue

Outline

TCP Congestion Control

end-end control (no network assistance)

sender limits transmission LastByteSent-LastByteAcked

CongWin Roughly

CongWin is dynamic function of perceived network congestion

How does sender perceive congestion

loss event = timeout or 3 duplicate acks

TCP sender reduces rate (CongWin) after loss event

three mechanisms AIMD slow start conservative after

timeout events

rate = CongWin

RTT Bytessec

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

multiplicative decrease cut CongWin in half after loss event

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

Long-lived TCP connection

TCP Slow Start

When connection begins CongWin = 1 MSS Example MSS = 500

bytes amp RTT = 200 msec

initial 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

RTT done by incrementing CongWin for every ACK received

Summary initial rate is slow but ramps up exponentially fast

Host A

one segment

RTT

Host B

time

two segments

four segments

Refinement After 3 dup ACKs

CongWin is cut in half window then grows linearly

But after timeout event CongWin instead set to 1 MSS window then grows exponentially to 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 CongWin gets to 12 of its value before timeout

Implementation Variable 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 Threshold set 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

Event State TCP Sender Action Commentary

ACK receipt for previously unacked data

Slow Start (SS)

CongWin = CongWin + MSS If (CongWin gt Threshold) set state to ldquoCongestion Avoidancerdquo

Resulting in a doubling of CongWin every RTT

CongestionAvoidance (CA)

CongWin = CongWin+MSS (MSSCongWin)

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

Loss event detected by triple duplicate ACK

SS or CA Threshold = CongWin2 CongWin = ThresholdSet state to ldquoCongestion Avoidancerdquo

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

Timeout SS or CA Threshold = CongWin2 CongWin = 1 MSSSet state to ldquoSlow Startrdquo

Enter slow start

Duplicate ACK

SS or CA Increment duplicate ACK count for segment being acked

CongWin and Threshold not changed

TCP throughput

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

Let W be the window size when loss occurs

When window is W throughput is WRTT Just after loss window drops to W2

throughput to W2RTT Average throughout 75 WRTT

TCP Futures

Example 1500 byte segments 100ms RTT want 10 Gbps throughput

Requires window size W = 83333 in-flight segments

Throughput in terms of loss rate

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

LRTT

MSS221

Fairness 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

TCP Fairness

Why is TCP fair

Two competing sessions Additive increase gives slope of 1 as throughout increases multiplicative decrease decreases throughput proportionally

R

equal bandwidth share

Connection 1 throughputConnect

ion 2

th

roughput

congestion avoidance additive increaseloss decrease window by factor of 2

Fairness (more)

Fairness and UDP Multimedia apps

often do not use TCP do not want rate

throttled by congestion control

Instead use UDP pump audiovideo at

constant rate tolerate packet loss

Research area TCP friendly

Fairness and parallel TCP connections

nothing prevents app from opening parallel cnctions between 2 hosts

Web browsers do this Example link of rate R

supporting 9 cnctions new app asks for 1 TCP

gets rate R10 new app asks for 11 TCPs

gets R2

Shrew

Very small but aggressive mammal that ferociously attacks and kills much larger animals with a venomous bite

Low-Rate Attacks TCP is vulnerable to low-rate DoS attacks

DoSRate

DoS I nter- burst Period

TC P

DoS

TCP a Dual Time-Scale Perspective

Two time-scales fundamentally required RTT time-scales (~10-100 ms)

bull AIMD control RTO time-scales (RTO=SRTT+4RTTVAR)

bull Avoid congestion collapse

Lower-bounding the RTO parameter [AllPax99] minRTO = 1 sec

bull to avoid spurious retransmissions RFC2988 recommends minRTO = 1 sec

Discrepancy between RTO and RTT tim e- scales isa key source of vulnerability to low rate attacks

The Low-Rate AttackVictim

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

A short burst (~RTT) sufficient to create outage

Outage ndash event of correlated packet losses that forces TCP to enter RTO mechanism

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

random initial phase

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

The outage synchronizes all TCP flows All flows react

simultaneously and identically

bull backoff for minRTO

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

Tim erandom initial phase

The Low-Rate Attack

Once the TCP flows try to recover ndash hit them again

Exploit protocol determinism

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

And keep repeatinghellip

RTT-time-scale outages inter-spaced on minRTO periods can deny service to TCP traffic

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

Delay modeling - homework

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

Ignoring congestion delay is influenced by

TCP connection establishment

data transmission delay slow start

Notation assumptions Assume one link between

client and server of rate R S MSS (bits) O object size (bits) no retransmissions (no loss no

corruption)

Window size First assume fixed congestion

window W segments Then dynamic window

modeling slow 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 case WSR lt RTT + SR

wait for ACK after sending windowrsquos worth of data sent

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

Where K=OWS

TCP Delay Modeling Slow Start (1)

Now suppose window grows according to slow start

Will show that the delay for one object is

R

S

R

SRTTP

R

ORTTLatency P )12(2

where P is the number of times TCP idles at server

1min KQP

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

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

RTT

initia te TCPconnection

requestobject

first w indow= S R

second w indow= 2S R

third w indow= 4S R

fourth w indow= 8S R

com pletetransm issionobject

delivered

tim e atc lient

tim e 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)

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

th window after the timeidle 2 1 kR

SRTT

R

S k

ementacknowledg receivesserver until

segment send tostartsserver whenfrom time RTTR

S

window kth the transmit totime2 1

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

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

Recall K = number of windows that cover object

How do we calculate K

Summary principles behind transport

layer services multiplexing

demultiplexing reliable data transfer flow control congestion control

instantiation and implementation in the Internet UDP TCP

Next leaving the network

ldquoedgerdquo (application transport layers)

into the network ldquocorerdquo

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 2: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Transport Layer 3-2

Connection-oriented transport TCP Overview and segment structure

bull RTT and RTO Reliable data transfer

bull Timeout and fast retransmit Flow control

bull Donrsquot overwhelm the receiver Connection management

Transport Layer 3-3

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

Transport Layer 3-4

Outline

Transport Layer 3-5

a top-10 problem

Transport Layer 3-6

no retransmission

Host B

out

Transport Layer 3-7

Host B

out

Transport Layer 3-8

in

out

=

in

out

gt

in

out

R2

R2in

ou

t

b

R2

R2in

ou

t

a

R2

R2in

ou

t

c

R4

R3

Transport Layer 3-9

in

Host B

out

Host A

Host B

o

u

t

path

Scalability issue

Outline

CongWin Roughly

timeout events

rate = CongWin

RTT Bytessec

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 3: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Transport Layer 3-3

client

FIN

server

ACK

FIN

close

closed

tim

ed w

ait

Transport Layer 3-4

Outline

Transport Layer 3-5

a top-10 problem

Transport Layer 3-6

no retransmission

Host B

out

Transport Layer 3-7

Host B

out

Transport Layer 3-8

in

out

=

in

out

gt

in

out

R2

R2in

ou

t

b

R2

R2in

ou

t

a

R2

R2in

ou

t

c

R4

R3

Transport Layer 3-9

in

Host B

out

Host A

Host B

o

u

t

path

Scalability issue

Outline

CongWin Roughly

timeout events

rate = CongWin

RTT Bytessec

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 4: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Transport Layer 3-4

Outline

Transport Layer 3-5

a top-10 problem

Transport Layer 3-6

no retransmission

Host B

out

Transport Layer 3-7

Host B

out

Transport Layer 3-8

in

out

=

in

out

gt

in

out

R2

R2in

ou

t

b

R2

R2in

ou

t

a

R2

R2in

ou

t

c

R4

R3

Transport Layer 3-9

in

Host B

out

Host A

Host B

o

u

t

path

Scalability issue

Outline

CongWin Roughly

timeout events

rate = CongWin

RTT Bytessec

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 5: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Transport Layer 3-5

a top-10 problem

Transport Layer 3-6

no retransmission

Host B

out

Transport Layer 3-7

Host B

out

Transport Layer 3-8

in

out

=

in

out

gt

in

out

R2

R2in

ou

t

b

R2

R2in

ou

t

a

R2

R2in

ou

t

c

R4

R3

Transport Layer 3-9

in

Host B

out

Host A

Host B

o

u

t

path

Scalability issue

Outline

CongWin Roughly

timeout events

rate = CongWin

RTT Bytessec

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 6: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Transport Layer 3-6

no retransmission

Host B

out

Transport Layer 3-7

Host B

out

Transport Layer 3-8

in

out

=

in

out

gt

in

out

R2

R2in

ou

t

b

R2

R2in

ou

t

a

R2

R2in

ou

t

c

R4

R3

Transport Layer 3-9

in

Host B

out

Host A

Host B

o

u

t

path

Scalability issue

Outline

CongWin Roughly

timeout events

rate = CongWin

RTT Bytessec

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 7: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Transport Layer 3-7

Host B

out

Transport Layer 3-8

in

out

=

in

out

gt

in

out

R2

R2in

ou

t

b

R2

R2in

ou

t

a

R2

R2in

ou

t

c

R4

R3

Transport Layer 3-9

in

Host B

out

Host A

Host B

o

u

t

path

Scalability issue

Outline

CongWin Roughly

timeout events

rate = CongWin

RTT Bytessec

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 8: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Transport Layer 3-8

in

out

=

in

out

gt

in

out

R2

R2in

ou

t

b

R2

R2in

ou

t

a

R2

R2in

ou

t

c

R4

R3

Transport Layer 3-9

in

Host B

out

Host A

Host B

o

u

t

path

Scalability issue

Outline

CongWin Roughly

timeout events

rate = CongWin

RTT Bytessec

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 9: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Transport Layer 3-9

in

Host B

out

Host A

Host B

o

u

t

path

Scalability issue

Outline

CongWin Roughly

timeout events

rate = CongWin

RTT Bytessec

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 10: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Host A

Host B

o

u

t

path

Scalability issue

Outline

CongWin Roughly

timeout events

rate = CongWin

RTT Bytessec

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 11: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

path

Scalability issue

Outline

CongWin Roughly

timeout events

rate = CongWin

RTT Bytessec

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 12: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

path

Scalability issue

Outline

CongWin Roughly

timeout events

rate = CongWin

RTT Bytessec

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 13: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

path

Scalability issue

Outline

CongWin Roughly

timeout events

rate = CongWin

RTT Bytessec

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 14: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Outline

CongWin Roughly

timeout events

rate = CongWin

RTT Bytessec

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 15: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

CongWin Roughly

timeout events

rate = CongWin

RTT Bytessec

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 16: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

TCP AIMD

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

TCP Slow Start

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 17: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

TCP Slow Start

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 18: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Host A

one segment

RTT

Host B

time

two segments

four segments

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 19: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Philosophy

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 20: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 21: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 22: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Slow Start (SS)

Enter slow start

Duplicate ACK

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 23: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

TCP throughput

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 24: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

TCP Futures

LRTT

MSS221

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 25: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 26: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Why is TCP fair

R

ion 2

th

roughput

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 27: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Fairness (more)

gets R2

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 28: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Shrew

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 29: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

DoSRate

TC P

DoS

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 30: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 31: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Attacker

TC

P S

en

din

g R

ate

Time

Do

S R

ate

Tim e

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 32: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

The Low-Rate Attack

Victim

Attacker

Do

S R

ate

Tim e

short burst (~RTT)

TC

P S

en

din

g R

ate

Tim e

outage

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 33: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 34: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

The Low-Rate Attack

Victim

AttackerTC

P S

en

din

g R

ate

Time

minRTO

Do

S R

ate

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 35: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

The Low-Rate Attack

Victim

Attacker

TC

P S

en

din

g R

ate

Tim e

minRTO minRTO

Do

S R

ate

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 36: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

DoSRate

TC P

DoS

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 37: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

corruption)

modeling slow start

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 38: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

delay = 2RTT + OR

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 39: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Where K=OWS

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 40: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

R

S

R

SRTTP

R

ORTTLatency P )12(2

1min KQP

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 41: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 42: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

R

S

R

SRTTPRTT

R

O

R

SRTT

R

SRTT

R

O

idleTimeRTTR

O

P

kP

k

P

pp

)12(][2

]2[2

2delay

1

SRTT

R

S k

S

R

Sk

RTT

requestobject

first w indow= S R

third w indow= 4S R

delivered

tim e atc lient

tim e atserver

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 43: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

)1(log

)1(logmin

12min

222min

2

110

S

OS

Okk

S

Ok

SOk

OSSSkK

k

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Page 44: Transport Layer3-1 Announcement r Homework 2 in tonight m Will be graded and sent back before Th. class r Midterm next Tu. in class m Review session next.

Announcement
Outline
Slide 8
Slide 10
Slide 13
Slide 14
TCP AIMD
TCP Slow Start
Refinement
Refinement (more)
TCP throughput
TCP Futures
TCP Fairness
Why is TCP fair
Fairness (more)
Shrew
Low-Rate Attacks
The Low-Rate Attack
Slide 32
Slide 33
Slide 34
Slide 35
Slide 36
Summary

Date post:	21-Dec-2015
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