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© Introduction to Internetworking – Alex Kooijman04/04/2000
Introduction to internetworking
Part Two
© Introduction to Internetworking – Alex Kooijman04/04/2000
Internet Protocol Suite
• IP and OSI/RM
• Internet Protocol
IP Packet
Type of Service
Address Resolution Protocol
• User Datagram Protocol
• Transmission Control Protocol
• IP addressing
© Introduction to Internetworking – Alex Kooijman04/04/2000
Application
Presentation
Session
Transport
Network
Data Link
Physical
7
6
5
4
3
2
1
TCP
IP
UDP
6 17
23 21 25 69
telnet
ftp
smtp
tftp
IP and OSI/RM
IP = Internet ProtocolUDP = User Datagram Protocol
© Introduction to Internetworking – Alex Kooijman04/04/2000
TIME TO LIVE PROTOCOL HEADER CHECKSUM
IDENTIFICATION
SERVICE TYPE
SOURCE IP ADDRESS
DESTINATION IP ADDRESS
IP OPTIONS (if any) PADDING
DATA
...
VERS HLEN TOTAL LENGTH
FRAGMENT OFFSET
0 4 8 16 19 24 31
FLAGS
IP Packet
© Introduction to Internetworking – Alex Kooijman04/04/2000
Precedence Delay Througput Relialbility Cost MBZ
000 routine001 priority010 intermediate011 flash100 flash override101 critical110 internetwork control111 network control
0= normal1= low
0= normal1= high
0= normal1= low
0= normal1= high
0= normal1= high
IP Type of Service Field
© Introduction to Internetworking – Alex Kooijman04/04/2000
10.16.69.56mac: 12345
10.16.69.205MAC: abcdeI want to connect to 10.16.69.205
what is the MAC address of 10.16.69.205?
Address Resolution Protocol (1)
© Introduction to Internetworking – Alex Kooijman04/04/2000
10.16.69.56mac: 12345
10.16.69.205MAC: abcde
I am 10.16.69.205my MAC address is abcde
Address Resolution Protocol (2)
© Introduction to Internetworking – Alex Kooijman04/04/2000
UDP uses no sequence or acknowledgment fields
UDP Datagram
SourcePort
Destination Port
Length Checksum Data
16 16 16
© Introduction to Internetworking – Alex Kooijman04/04/2000
ACKNOWLEDGEMENT NUMBER
SEQUENCE NUMBER
SOURCE PORT
HLEN reserved CODE BITS
CHECKSUM URGENT POINTER
WINDOW
OPTIONS (if any) PADDING
DATA
...
DESTINATION PORT
0 4 10 16 24 31
TCP Segment
© Introduction to Internetworking – Alex Kooijman04/04/2000
Send SYN (seq=100 ctl=SYN)
Host A Host B
1
TCP Three Way Handshake (1)
© Introduction to Internetworking – Alex Kooijman04/04/2000
Send SYN (seq=100 ctl=SYN)
SYN received
Host A Host B
SYN received
1
2
Send SYN (seq=300 ack=101 ctl=syn,ack)
TCP Three Way Handshake (2)
© Introduction to Internetworking – Alex Kooijman04/04/2000
Send SYN (seq=100 ctl=SYN)
SYN received
Send SYN (seq=300 ack=101 ctl=syn,ack)
Send ACK(seq=101 ack=301 ctl=ack)
Host A Host B
SYN received
1
2
3
ACK receivedconnection is established
TCP Three Way Handshake (3)
© Introduction to Internetworking – Alex Kooijman04/04/2000
IP Addressing
• 32 bits represented in 4 decimal numbers, each representing 8 bits
• host part• network part• A, B, C, D, E class network numbers• two types of broadcast:
directed broadcast local network broadcast
© Introduction to Internetworking – Alex Kooijman04/04/2000
32 Bits
IP Addressing
Class A : Network-part = 8 bits, Host-Part = 24 bitsClass B : Network-part = 16 bits, Host-Part = 16 bitsClass C : Network-part = 24 bits, Host-part = 8 bits
Class D : multicastClass E : experimental
Network part Host part
© Introduction to Internetworking – Alex Kooijman04/04/2000
172.16.3.0/24
Broadcast to255.255.255.255
Notforwardedby router
172.16.4.0/24
172.16.5.0/24
IP Local Broadcast
© Introduction to Internetworking – Alex Kooijman04/04/2000
Broadcast to172.16. 4.255
forwardedby router
172.16.3.0/24
172.16.4.0/24
172.16.5.0/24
IP Directed Broadcast
© Introduction to Internetworking – Alex Kooijman04/04/2000
IP Subnetting
• Classless interdomain Routing (CIDR) route is known as address and mask supernetting and subnetting
• Variable Length Subnet Mask (VLSM) RFC1009 classfull networks can be split into multiple
networks with larger subnet masks
© Introduction to Internetworking – Alex Kooijman04/04/2000
Class B Subnetting
# Bits Subnet Mask # Subnets # Hosts2 255.255.192.0 2 163823 255.255.224.0 6 81904 255.255.240.0 14 40945 255.255.248.0 30 20466 255.255.252.0 62 10227 255.255.254.0 126 5108 255.255.255.0 254 2549 255.255.255.128 510 12610 255.255.255.192 1022 6211 255.255.255.224 2046 3012 255.255.255.240 4094 1413 255.255.255.248 8190 614 255.255.255.252 16382 2
IP Subnetting
© Introduction to Internetworking – Alex Kooijman04/04/2000
Internet Control Message Protocol
• Required on every IP stack• provides feedback about problems
time to live counter expires congestion failures destination not reachable
• direct into IP
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