Post on 29-Dec-2015
transcript
2
Upon completion of this chapter you will be able to perform the following tasks:
• Describe how the TCP/IP implementation relates to the OSI reference model
• Identify the functions of the TCP/IP network-layer protocols
• Identify the functions of the TCP/IP transport-layer protocols
Objectives
3
• Early of 1970s Developed as part of the research done by the Defense Advanced Research Projects Agency (DARPA) Later TCP/IP was included with the Berkeley Software Distribution (BSD) of UNIX
• Universal
Introduction to TCP/IP
UNIX Host
Internet
TCP/IP
UNIX Host
4
TCP/IP Protocol StackMap DOD model to the OSI Reference Model
Application
Presentation
Session
Transport
Network
Data Link
Physical
7
6
5
4
3
2
1
Application
Transport
Internet
Network Interface
OSI Reference Model
Ethernet, 802.3, 802.5, FDDI, and so on.
TCP/IP Conceptual Layers
US Department Of Defence (DOD)
6
Network Layer Overview
• OSI network layer corresponds to the TCP/IP internet layer
Internet Protocol (IP)
Internet Control MessageProtocol (ICMP)
Address ResolutionProtocol (ARP)
Reverse AddressResolution Protocol (RARP)
Internet Protocol (IP)
Internet Control MessageProtocol (ICMP)
Address ResolutionProtocol (ARP)
Reverse AddressResolution Protocol (RARP)
Application
Transport
Internet
Network Interface
Hardware
7
IP Datagram
# Bits 616 32 416 6 32
VERS HLENType ofService
TotalLength
Identi-fication
FlagsFrag
OffsetTTL
4
# Bits 16 32 416 32
ProtocolHeader
ChecksumSource IPAddress
Destination IPAddress
IPOptions
Data…
4
Network Header
SegmentHeader
FrameTrailer
FrameHeader
Data
9
• Unique addressing allows communication between end stations
• Path choice is based on location• Location is represented by an address
Introduction to TCP/IP Addresses
UNIX HostUNIX Host
Company ACompany B
172.16.3.10 10.250.8.11
11
IP Addressing
32 Bits
Network Host
8 Bits 8 Bits 8 Bits 8 Bits
10101100 00010000 1100110001111010
12
IP Addressing
32 Bits
Network Host
8 Bits
172 . 16 . 122 . 204
8 Bits 8 Bits 8 Bits
10101100 00010000 1100110001111010
00000000 ~ 11111111 (binary) ––– 0 ~ 255 (Decimal)
13
• Class A:
• Class B:
• Class C:
• Class D: For Multicast
• Class E: For ResearchN = Network number H = Host number
IP Address Classes
N H H H
N N H H
N N N H
15
IP Address Bit Patterns
1 7 24Class A:# Bits 14 16Class B:# Bits 0 network # host #1 network # host #0
2
16
IP Address Bit Patterns
1 7 24
Class A:
# Bits
14 16
Class B:
# Bits
3 21 8
Class C:
# Bits
0 network # host #
1 network # host #0
1 network # host #1 0
2
18
• Network 172.16.0.0
• Host 0.0.3.10
• Host 0.0.3.15
172.16.0.0
Addressing Example
172.16.3.10172.16.3.15
19
Recognizing Classes in IP Addresses (First Octet Rule)
High OrderBits (binary)
Octet inDecimal
AddressClass
0
10
110
1110
1111
1 – 126
128 – 191
192 – 223
224 – 239
240 – 255
A
B
C
D
E
Network 127.0.0.0 Reserved for loopback. The address 127.0.0.1 often is used to refer to the local host
20
Address Rule:· All network bits set to 0 Refers to a host on “this” network For example, 0.0.0.34 would address node 34 on the local network
· All host bits set to 0 Refers to the network itself For example, the address 172.16.0.0 can be used to refer to network 172.16
· All network bits set to 1 Refers to a Subnet Mask For example, the address 255.255.0.0
· All host bits set to 1 Refers to Broadcast Addresses For example, the address 172.16. 255.255
· 255.255.255.255 Refers to a broadcast meant for hosts on this network only
· Network 0.0.0.0 Refers to the default route
21
Network And Host Number
AddressClass
Network Number
Host Number
A
B
C
126
16,384
2,097,152
16,777,214
65,534
254
Network
126= 27-1 (127.0.0.0 Reserved)
16384 = 214
2,097,152 = 221
Host
16,777,214 = 224 - 2
65,534 = 216 - 2
254 = 28 - 2
22
Address Class Network Host
10.2.1.1
128.63.2.100
201.222.5.64
192.6.141.2
130.113.64.16
256.241.201.10
Exercise: IP Address Classes
23
Address Class Network Host
Exercise: IP Address Classes
10.2.1.1
128.63.2.100
201.222.5.64
192.6.141.2
130.113.64.16
256.241.201.10
A
24
Exercise: IP Address Classes
Address Class Network Host
10.2.1.1
128.63.2.100
201.222.5.64
192.6.141.2
130.113.64.16
256.241.201.10
A 10.0.0.0
25
Exercise: IP Address Classes
Address Class Network Host
10.2.1.1
128.63.2.100
201.222.5.64
192.6.141.2
130.113.64.16
256.241.201.10
A 0.2.1.1 10.0.0.0
26
Exercise: IP Address Classes
Address Class Network Host
10.2.1.1
128.63.2.100
201.222.5.64
192.6.141.2
130.113.64.16
256.241.201.10
A
B
0.2.1.1 10.0.0.0
27
Exercise: IP Address Classes
Address Class Network Host
10.2.1.1
128.63.2.100
201.222.5.64
192.6.141.2
130.113.64.16
256.241.201.10
A
B 128.63.0.0
0.2.1.1 10.0.0.0
28
Exercise: IP Address Classes
Address Class Network Host
10.2.1.1
128.63.2.100
201.222.5.64
192.6.141.2
130.113.64.16
256.241.201.10
A
B 0.0.2.100 128.63.0.0
0.2.1.1 10.0.0.0
29
Exercise: IP Address Classes
Address Class Network Host
10.2.1.1
128.63.2.100
201.222.5.64
192.6.141.2
130.113.64.16
256.241.201.10
A
B
C
0.0.2.100 128.63.0.0
0.2.1.1 10.0.0.0
30
Exercise: IP Address Classes
Address Class Network Host
10.2.1.1
128.63.2.100
201.222.5.64
192.6.141.2
130.113.64.16
256.241.201.10
A
B
C 201.222.5.0
0.0.2.100 128.63.0.0
0.2.1.1 10.0.0.0
31
Exercise: IP Address Classes
Address Class Network Host
10.2.1.1
128.63.2.100
201.222.5.64
192.6.141.2
130.113.64.16
256.241.201.10
A
B
C 0.0.0.64 201.222.5.0
0.0.2.100 128.63.0.0
0.2.1.1 10.0.0.0
32
Exercise: IP Address Classes
Address Class Network Host
10.2.1.1
128.63.2.100
201.222.5.64
192.6.141.2
130.113.64.16
256.241.201.10
A
B
C
C
B 0.0.64.16 130.113.0.0
0.0.0.2 192.6.141.0
0.0.0.64 201.222.5.0
0.0.2.100 128.63.0.0
0.2.1.1 10.0.0.0
Nonexistent
00000000 ~ 11111111 (binary) ––– 0 ~ 255 (Decimal)
33
The Internet is controlled by a number of bodies
ISOC (Internet Society)—non-profit society coordinating internet evolution and use.
IANA (Internet Assigned Numbers Authority)—organization
operated under ISOC as part of the Internet Architecture Board
(IAB). Delegates authority for IP address space allocation and
domain name assignment to the InterNIC and other organizations.
InterNIC (Network Information Center)—an independent agency
that makes rules, administers the registration process, and
maintains the official database of registered domain names. The
Domain Name System (DNS) is a set of distributed databases
containing these numeric equivalents and their corresponding
domain names. With the DNS system users may use an easy-to-
remember name (yourname.com) rather than a difficult string of
numbers when seeking out a site on the Internet.
34
Addresses for Private Networks
Class Beginning Address Ending Address
Class A 10.0.0.0 10.255.255.255
Class B 172.16.0.0 172.31.255.255
Class C 192.168.0.0 192.168.255.255
The others are registered addresses
If you are connected to the Internet, you must use
registered addresses
36
Host Addresses172.16.2.2
172.16.3.10
172.16.12.12
IP: 172.16.2.1
10.1.1.1
10.250.8.11
10.180.30.118
IP: 10.6.24.2
E0 E1
172.16 12 12
Network Host
. . Network Interface
172.16.0.0
10.0.0.0
E0
E1
Routing Table
38
• Network 172.16.0.0
Addressing with Subnets
172.16.1.0 172.16.2.0
172.16.3.0
172.16.4.0
Company A 172.18.0.0
172.16.0.0 172.17.0.0
39
Subnet Addressing172.16.?.200
172.16.?.2
172.16. ?.160
172.16.?.5
172.16. ?.100
172.16. ?.150
E0 E1
Network Interface
172.16.0.0
172.16.0.0
E0
E1
Routing Table
40
Subnet Addressing172.16.2.200
172.16.2.2
172.16.2.160
IP: 172.16.2.1
172.16.3.5
172.16.3.100
172.16.3.150
IP: 172.16.3.1
E0 E1
172.16 2 160
Network Host
. .
Subnet
172.16 3 100
Network Host
. .
Subnet
Network Interface
172.16.2.0
172.16.3.0
E0
E1
New Routing Table
43
Subnet Mask
172 16 0 0
255 255 0 0
255 255 255 0
IPAddress
DefaultSubnet
Mask
Additional 8-bitSubnet
Mask
Network Host
Borrow from host bits, starting at the high order bit position
Network Host
Network Subnet Host
44
Decimal Equivalents of Bit Patterns
1 0 0 0 0 0 0 0 = 128
1 1 0 0 0 0 0 0 = 192
1 1 1 0 0 0 0 0 = 224
1 1 1 1 0 0 0 0 = 240
1 1 1 1 1 0 0 0 = 248
1 1 1 1 1 1 0 0 = 252
1 1 1 1 1 1 1 0 = 254
1 1 1 1 1 1 1 1 = 255
128 64 32 16 8 4 2 1
45
Network Host
172.16.2.160
255.255.0.0
172 16 0 0
10101100
11111111
10101100
00010000
11111111
00010000
00000000
00000000
10100000
00000000
00000000
• Subnets not in use—the default
00000010
Standard Address without Subnets
46
Network Host
172.16.2.160
255.255.255.0
172 16 2 0
Subnet
11111111 11111111 0000000011111111
• Network number extended by eight bits
10101100
10101100
00010000
00010000 00000010
10100000
00000000
00000010
Subnet Mask with Subnets
47
Network Host
172.16.98.160
255.255.224.0
172 16 96 0
Subnet
11111111 11111111 0000000011100000
• Network number extended by variable bits
10101100
10101100
00010000
00010000 01100000
10100000
00000000
01100010
Subnet Mask with Subnets
48
Decimal Equivalents of Bit Patterns
1 0 0 0 0 0 0 0 = 128
1 1 0 0 0 0 0 0 = 192
1 1 1 0 0 0 0 0 = 224
1 1 1 1 0 0 0 0 = 240
1 1 1 1 1 0 0 0 = 248
1 1 1 1 1 1 0 0 = 252
1 1 1 1 1 1 1 0 = 254
1 1 1 1 1 1 1 1 = 255
128 64 32 16 8 4 2 1
49
Exercise: Subnet Masks
Address Subnet Mask Class Subnet
172.16.2.10
10.13.24.20
10.30.36.12
255.255.255.0
255.252.0.0
255.255.255.0
50
Exercise: Subnet Masks
Address Subnet Mask Class Subnet
172.16.2.10
10.13.24.20
10.30.36.12
255.255.255.0
255.252.0.0
255.255.255.0
B
51
Exercise: Subnet Masks
Address Subnet Mask Class Subnet
172.16.2.10
10.13.24.20
10.30.36.12
255.255.255.0
255.252.0.0
255.255.255.0
B 172.16.2.0
52
Exercise: Subnet Masks
Address Subnet Mask Class Subnet
172.16.2.10
10.13.24.20
10.30.36.12
255.255.255.0
255.252.0.0
255.255.255.0
B
A
172.16.2.0
53
Exercise: Subnet Masks
Address Subnet Mask Class Subnet
172.16.2.10
10.13.24.20
10.30.36.12
255.255.255.0
255.252.0.0
255.255.255.0
B
A
172.16.2.0
10.12.0.0
10.13.24.20
255.252.0.0 11111111 11111100 0000000000000000
00001010
00001010
00001101
00001100 00000000
00010100
00000000
00011000
10 . 12 . 0 . 0
54
Exercise: Subnet Masks
Address Subnet Mask Class Subnet
172.16.2.10
10.13.24.20
10.30.36.12
255.255.255.0
255.252.0.0
255.255.255.0
B
A
A
172.16.2.0
10.12.0.0
55
Exercise: Subnet Masks
Address Subnet Mask Class Subnet
172.16.2.10
10.13.24.20
10.30.36.12
255.255.255.0
255.252.0.0
255.255.255.0
B
A
A
172.16.2.0
10.12.0.0
10.30.36.0
56
Subnet Planning
Other subnets
20 subnets
5 hosts per subnet
Class C address: 201.222.5.0
20 subnets
5 hosts per subnet
Class C address: 201.222.5.0
201.222.5.16
201.222.5.32 201.222.5.48
20 subnets5 Bits of Subnet 25=32 Subnets
5 hosts per subnet3 Bits of Host 23-2= 6 Hosts
20 subnets5 Bits of Subnet 25=32 Subnets
5 hosts per subnet3 Bits of Host 23-2= 6 Hosts
57
IP Host Address: 201.222.5.121Subnet Mask: 255.255.255.248
Network Subnet Host
201 222 5 120
201.222.5.121: 11001001
11111111
Subnet: 11001001 11011110
11011110
11111111
00000101
00000101
11111111
01111 001
11111 000
01111 000
255.255.255.248:
Class C Subnet Planning Example
• Subnet Address = 201.222.5.120• Host Addresses = 0.0.0.1• Rang = 201.222.5.121–201.222.5.126• Broadcast Address = 201.222.5.127• Five Bits of Subnetting
58
IP Host Address: 172.16.2.120Subnet Mask: 255.255.255.0
• Subnet Address = 172.16.2.0• Host Addresses = 172.16.2.1–172.16.2.254• Broadcast Address = 172.16.2.255• Eight bits of subnetting
Network Subnet Host
172 16 2 0
172.16.2.120:
255.255.255.0:
10101100
11111111
Subnet: 10101100 00010000
00010000
11111111
00000010
00000010
11111111
01111001
00000000
00000000
Class B Subnet Planning Example
59
Broadcast Addresses
172.16.1.0
172.16.2.0
172.16.3.0
172.16.4.0
172.16.3.255(Directed broadcast)
255.255.255.255(Local network broadcast)
XX
60
Exercise: Broadcast Addresses
Address Class Subnet Broadcast
201.222.10.60 255.255.255.248
Subnet Mask
15.16.193.6 255.255.248.0
128.16.32.13 255.255.255.252
61
Address Class Subnet Broadcast
201.222.10.60 255.255.255.248 C
Subnet Mask
15.16.193.6 255.255.248.0
128.16.32.13 255.255.255.252
Exercise: Broadcast Addresses
62
Address Class Subnet Broadcast
201.222.10.60 255.255.255.248 C 201.222.10.56
Subnet Mask
15.16.193.6 255.255.248.0
128.16.32.13 255.255.255.252
Exercise: Broadcast Addresses
60 --- 00111100 56 --- 00111000
63
Address Class Subnet Broadcast
201.222.10.60 255.255.255.248 C 201.222.10.63201.222.10.56
Subnet Mask
15.16.193.6 255.255.248.0
128.16.32.13 255.255.255.252
Exercise: Broadcast Addresses
63 --- 0011111156 --- 0011100060 --- 00111100
64
Address Class Subnet Broadcast
201.222.10.60 255.255.255.248 C 201.222.10.63201.222.10.56
Subnet Mask
15.16.193.6 255.255.248.0 A
128.16.32.13 255.255.255.252
Exercise: Broadcast Addresses
65
Address Class Subnet Broadcast
201.222.10.60 255.255.255.248 C 201.222.10.63201.222.10.56
Subnet Mask
15.16.193.6 255.255.248.0 A 15.16.192.0
128.16.32.13 255.255.255.252
Exercise: Broadcast Addresses
193 --- 11000001 192 --- 11000000
66
Address Class Subnet Broadcast
201.222.10.60 255.255.255.248 C 201.222.10.63201.222.10.56
Subnet Mask
15.16.193.6 255.255.248.0 A 15.16.199.25515.16.192.0
128.16.32.13 255.255.255.252
Exercise: Broadcast Addresses
199 --- 11000111255 --- 11111111
192 --- 11000000193 --- 11000001
67
Address Class Subnet Broadcast
201.222.10.60 255.255.255.248 C 201.222.10.63201.222.10.56
Subnet Mask
15.16.193.6 255.255.248.0 A 15.16.199.25515.16.192.0
128.16.32.13 255.255.255.252 B
Exercise: Broadcast Addresses
68
Address Class Subnet Broadcast
201.222.10.60 255.255.255.248 C 201.222.10.63201.222.10.56
Subnet Mask
15.16.193.6 255.255.248.0 A 15.16.199.25515.16.192.0
128.16.32.13 255.255.255.252 B 128.16.32.12
Exercise: Broadcast Addresses
12 --- 0000110013 --- 00001101
69
Address Class Subnet Broadcast
201.222.10.60 255.255.255.248 C 201.222.10.63201.222.10.56
Subnet Mask
15.16.193.6 255.255.248.0 A 15.16.199.25515.16.192.0
128.16.32.13 255.255.255.252 B 128.16.32.15128.16.32.12
Exercise: Broadcast Addresses
15 --- 0000111112 --- 0000110013 --- 00001101
70
• IP addresses are specified in 32-bit dotted-decimal format that indicates class, network, and host identifications
• Subnet masks are used to indicate the boundary between network, subnet, and host IDs
• Subnet Planning
• Broadcast Addresses
• Subnets with all [0]s or all [1]s reserved
IP addresses Summary
71
Internet Control Message Protocol
Application
Transport
Internet
Network Interface
Hardware
ICMP
Destination Unreachable
Echo (Ping)
Other
ICMP messages are carried in IP datagrams and are used to send error and control messages
72
Internet Control Message Protocol
Application
Transport
Internet
Network Interface
Hardware
ICMP
Destination Unreachable
Echo (Ping)
Other
· Destination Unreachable · Time Exceeded · Parameter Problem · Source Quench · Redirect · Echo Request· Echo Reply · Timestamp · Timestamp Reply · Information Request · Information Reply · Address Request · Address Reply
73
ICMP Testing
• Destination unreachable–Host or port unreachable
–Network unreachable
Host AI do not know how to get to Z.Send ICMP.
To Z
Destination Unreachable
Send data to Z.
DataNetwork
75
ICMP Testing (cont.)
• Generated by the ping command
AYes, I am here.Is B reachable?
B
ICMP Echo Request
76
ICMP Testing (cont.)
• Generated by the ping command
AYes, I am here.
ICMP Echo Reply
Is B reachable?
B
ICMP Echo Request
77
Address Resolution Protocol
172.16.3.1 172.16.3.2
IP: 172.16.3.2 = ???
I need the Ethernet address of 176.16.3.2.
78
Address Resolution Protocol
172.16.3.1
IP: 172.16.3.2 Ethernet: 0800.0020.1111
172.16.3.2
IP: 172.16.3.2 = ???
I need the Ethernet address of 176.16.3.2.
I heard that broadcast. The message is for me. Here is my Ethernet address.
79
Address Resolution Protocol
• Map IP Ethernet
• Local ARP
172.16.3.1
IP: 172.16.3.2 Ethernet: 0800.0020.1111
172.16.3.2
IP: 172.16.3.2 = ???
I need the Ethernet address of 176.16.3.2.
I heard that broadcast. The message is for me. Here is my Ethernet address.
Example 1: Destination local
80
Finding the MAC Address
Router A
Example 2: Destination not local
Host Z
Host YQuery
BroadcastBroadcast Host ZMAC ?Host ZMAC ? Host ZHost Z
Response
Host YMAC
Host YMAC
Router AMAC
Router AMAC
Routing Table:Net forHost Z
Routing Table:Net forHost Z
• Map IP Ethernet
• Not Local ARP
82
Transport Layer Overview
Transmission ControlProtocol (TCP)
User Datagram Protocol (UDP)
Transmission ControlProtocol (TCP)
User Datagram Protocol (UDP)
Application
Transport
Internet
Network Interface
Hardware
TCP : Connection-oriented services
UDP : Connectionless services
83
• Determines destination upper-layer protocol
IP Datagram Protocol Field
TransportLayer
InternetLayer
TCP UDP
ProtocolNumbers
IP
176
84
IP Datagram
# Bits 616 32 416 6 32
VERS HLENType ofService
TotalLength
Identi-fication
FlagsFrag
OffsetTTL
4
# Bits 16 32 416 32
ProtocolHeader
ChecksumSource IPAddress
Destination IPAddress
IPOptions
Data…
4
Network Header
SegmentHeader
FrameTrailer
FrameHeader
Data
85
TCP Segment Format
# Bits 616 32 416 6 32
SourcePort
Dest.Port
SequenceNumber
AcknowledgementNumber
HLEN ReservedCodeBits
16
Window
16
Check-sum
16
Urgent
0 or 32
Option Data...
86
Port Numbers
TCP
Port Numbers
FTP
TransportLayer
TELNET
DNS
SNMP
TFTP
SMTP
UDP
ApplicationLayer
21 23 25 53 69 161
87
Port Numbers assigned range
Port numbers have the following assigned ranges:
Port number are 16 bits long (0~65536)
• Numbers below 1 to 255 are for public applications
(well-known port number )
• Numbers from 256 to 1023 are assigned to
companies for saleable applications
• Numbers above 1023 are unregulated
88
Identify Service
172.16.1.51
72.16.1.2
172.16.1.1
Client_1 Client_2
DNS FTPServer
1028 53 …
SP DP 1028 21 …
SP DP
53 21
172.16.1.101
89
TCP Port Numbers
SourcePort
Dest.Port
…
Host A
Dest. port = 23.Send packet to my
Telnet application.
1028 23 …
SP DP
Host ZTelnet Z
90
Send SYN (seq=100 ctl=SYN)
Host A Host B
1
TCP Three-Way Handshake/Open Connection
SYN received (seq=100)
91
Send SYN (seq=100 ctl=SYN)
SYN received (seq=100 )
Send SYN (seq=300 ack=101 ctl=syn,ack)
Host A Host B
1
2SYN received (seq=300 ack=101)
TCP Three-Way Handshake/Open Connection
92
Send SYN (seq=100 ctl=SYN)
SYN received (seq=100 )
Send SYN (seq=300 ack=101 ctl=syn,ack)
Send ack(ack=301 ctl=ack)
Host A Host B
1
2
3
SYN received (seq=300 ack=101)
TCP Three-Way Handshake/Open Connection
93
TCP Three-Way Handshake/Open Connection
Send SYN (seq=100 ctl=SYN)
SYN received (seq=100 )
Send SYN (seq=300 ack=101 ctl=syn,ack)
Send ack(ack=301 ctl=ack)
Host A Host B
Established Connection (seq=101 ctl= Data)
1
2
3
SYN received (seq=300 ack=101)
SYN received (ack=301 )
96
Window size = 3Send 2
TCP WindowingSender ReceiverWindow size = 3
Send 1
Window size = 3Send 3
ACK 1Window size = 2
ACK 2Window size = 2
ACK 3Window size = 2
97
Window size = 3Send 5
Window size = 3Send 2
TCP WindowingSender ReceiverWindow size = 3
Send 1
Window size = 3Send 4
Window size = 3Send 3
ACK 1Window size = 2
ACK 2Window size = 2
ACK 3Window size = 2
98
Window size = 3Send 5
Window size = 3Send 2
TCP WindowingSender ReceiverWindow size = 3
Send 1
Window size = 3Send 4
Window size = 3Send 3
ACK 1Window size = 2
ACK 2Window size = 2
ACK 3Window size = 2
ACK 4Window size = 2
ACK 5Window size = 2
99
TCP Sequence and Acknowledgment Numbers
I justsent #10.
SourcePort
Dest.Port
…Sequence
#Acknowledgement
#
1028 23
Source Dest.
1010
Seq.
0
Ack.
…
100
TCP Sequence and Acknowledgment Numbers
I justsent #10.
I just got #10,now I need #11.
SourcePort
Dest.Port
…Sequence
#Acknowledgement
#
1028 23
Source Dest.
1010
Seq.
1
Ack.
…
102823
Source Dest.
1111
Seq.
1
Ack.
…
101
TCP Sequence and Acknowledgment Numbers
I justsent #10.
I just got #10,now I need #11.
SourcePort
Dest.Port
…Sequence
#Acknowledgement
#
1028 23
Source Dest.
1010
Seq.
1
Ack.
…
1028 23
Source Dest.
1111
Seq.
2
Ack.
…
102823
Source Dest.
1111
Seq.
1
Ack.
…
Sequence and Reliability
102
• UDP no sequence or acknowledgment fields
• Application-layer protocols can provide for reliability
UDP Segment Format
16
SourcePort
16
DestinationPort
16
Length
16
Checksum Data…
# Bits
103
Application Layer Overview
*Used by the router
Application
Transport
Internet
Network Interface
Hardware
File Transfer- TFTP *- FTP- NFS
E-Mail- SMTP
Remote Login- Telnet *- rlogin
Network Management- SNMP *
Name Management- DNS*
File Transfer- TFTP *- FTP- NFS
E-Mail- SMTP
Remote Login- Telnet *- rlogin
Network Management- SNMP *
Name Management- DNS*
104
FTP Service
· FTP enables a user to transfer files between two
networked computers.
· FTP also provides a variety of login, directory
inspection, file manipulation, and other session
control functions.
· FTP can be used to move files between disparate
local operating systems
105
SMTP Service
Simple Mail Transfer Protocol is an electronic
mail routing protocol that uses TCP and IP to
route mail messages between network hosts.
106
Remote Terminal Emulation allows users to
access host-based applications over the network,
with personal computers functioning as dumb
terminals.
Like FTP, TELNET can provide connectivity
between dissimilar systems (for example, DOS and
UNIX).
It has been one of the most widely used network
applications.
TELNET Service
107
DNS Service
The domain name can be up to 255 characters long and is not case-sensitive (each label can have up to 63 characters)
108
172.16.2.2172.16.1.2
172.16.1.1172.16.2.1
www.sun.comftp.sun.com
DNS Server
www.sun.com 172.16.1.2
ftp.sun.com 172.16.2.2
: : : : : : : : : : : : : : :
DNS Table
DNS Service
111
IPv6 (IP version 6) addresses
128-bit addresses
Will replace IPv4
Quality-of-Service Capabilities
Authentication and Privacy Capabilities
IPv6
Only 6% of IPv4 addresses are unassigned
112
• Describe how the TCP/IP implementation relates to the OSI
reference model
• The functions of the TCP/IP network-layer protocols
IP addresses are specified in 32-bit dotted-decimal format
that indicates class, network, and host identifications.
Subnet masks are used to indicate the boundary between
network, subnet, and host IDs
ICMP
ARP/RARP
Summary