1. © Introduction to Internetworking – Alex Kooijman 04/04/2000 Introduction to internetworking Part Two

2. © Introduction to Internetworking – Alex Kooijman 04/04/2000 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

3. © Introduction to Internetworking – Alex Kooijman 04/04/2000 Application Presentation Session Transport Network Data Link Physical 7 6 5 4 3 2 1 TCP IP UDP 617 23212569 telnet ftp smtp tftp IP and OSI/RM IP = Internet Protocol UDP = User Datagram Protocol

4. © Introduction to Internetworking – Alex Kooijman 04/04/2000 TIME TO LIVEPROTOCOLHEADER CHECKSUM IDENTIFICATION SERVICE TYPE SOURCE IP ADDRESS DESTINATION IP ADDRESS IP OPTIONS (if any)PADDING DATA... VERSHLENTOTAL LENGTH FRAGMENT OFFSET 04816192431 FLAGS IP Packet

5. © Introduction to Internetworking – Alex Kooijman 04/04/2000 PrecedenceDelayThrougputRelialbilityCostMBZ 000 routine 001 priority 010 intermediate 011 flash 100 flash override 101 critical 110 internetwork control 111 network control 0= normal 1= low 0= normal 1= high 0= normal 1= low 0= normal 1= high IP Type of Service Field

6. © Introduction to Internetworking – Alex Kooijman 04/04/2000 10.16.69.56 mac: 12345 10.16.69.205 MAC: abcde I want to connect to 10.16.69.205 what is the MAC address of 10.16.69.205? Address Resolution Protocol (1)

7. © Introduction to Internetworking – Alex Kooijman 04/04/2000 10.16.69.56 mac: 12345 10.16.69.205 MAC: abcde I am 10.16.69.205 my MAC address is abcde Address Resolution Protocol (2)

8. © Introduction to Internetworking – Alex Kooijman 04/04/2000 UDP uses no sequence or acknowledgment fields UDP Datagram Source Port Destination Port LengthChecksumData 16

9. © Introduction to Internetworking – Alex Kooijman 04/04/2000 ACKNOWLEDGEMENT NUMBER SEQUENCE NUMBER SOURCE PORT HLEN reserved CODE BITS CHECKSUM URGENT POINTER WINDOW OPTIONS (if any)PADDING DATA... DESTINATION PORT 0410162431 TCP Segment

10. © Introduction to Internetworking – Alex Kooijman 04/04/2000 Send SYN (seq=100 ctl=SYN) Host AHost B 1 TCP Three Way Handshake (1)

11. © Introduction to Internetworking – Alex Kooijman 04/04/2000 Send SYN (seq=100 ctl=SYN) SYN received Host AHost B SYN received 1 2 Send SYN (seq=300 ack=101 ctl=syn,ack) TCP Three Way Handshake (2)

12. © Introduction to Internetworking – Alex Kooijman 04/04/2000 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 AHost B SYN received 1 2 3 ACK received connection is established TCP Three Way Handshake (3)

13. © Introduction to Internetworking – Alex Kooijman 04/04/2000 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

14. © Introduction to Internetworking – Alex Kooijman 04/04/2000 32 Bits IP Addressing Class A:Network-part = 8 bits, Host-Part = 24 bits Class B:Network-part = 16 bits, Host-Part = 16 bits Class C:Network-part = 24 bits, Host-part = 8 bits Class D : multicast Class E : experimental Network partHost part

15. © Introduction to Internetworking – Alex Kooijman 04/04/2000 172.16.3.0/24 Broadcast to 255.255.255.255 Not forwarded by router 172.16.4.0/24 172.16.5.0/24 IP Local Broadcast

16. © Introduction to Internetworking – Alex Kooijman 04/04/2000 Broadcast to 172.16. 4.255 forwarded by router 172.16.3.0/24 172.16.4.0/24 172.16.5.0/24 IP Directed Broadcast

17. © Introduction to Internetworking – Alex Kooijman 04/04/2000 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

18. © Introduction to Internetworking – Alex Kooijman 04/04/2000 Class B Subnetting # BitsSubnet Mask# Subnets# Hosts 2255.255.192.0216382 3255.255.224.068190 4255.255.240.0144094 5255.255.248.0302046 6255.255.252.0621022 7255.255.254.0126510 8255.255.255.0254254 9255.255.255.128510126 10255.255.255.192102262 11255.255.255.224204630 12255.255.255.240409414 13255.255.255.24881906 14255.255.255.252163822 IP Subnetting

19. © Introduction to Internetworking – Alex Kooijman 04/04/2000 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

20. © Introduction to Internetworking – Alex Kooijman 04/04/2000 Internet Control Message Protocol Messages:  Echo request/reply  Destination Unreachable  Source quench  Redirect  Time Exceeded  parameter problem  timestamp request/reply  information request/reply  address mask request/reply