1. Lecture 15 Internetworking: Address Structure Fragmentation and Reassembly

3. Protocol layers across an internetwork

4. IP-service model Datagram Best Effort Error reporting

6. IP-datagrams crossing a network with various MTU’s

7. Header Fields for IP over ethernet

8. IP-Address Classes

9. IP Addresses Dotted Decimal Representation 01111111.00000101.11111111.00111111 255.255.255.255—broadcast address 0.0.0.0-forbidden

10. Hierarchy and Network Classes

11. Datagram Forwarding Host and routers with same network address can communicate directly Routers exchange packets between networks

12. if(NetworkNum of dest.=NetworkNum of one of my interfaces) then deliver packet to destination over that interface else if (NetworkNium of dest. is in my forwarding table) then deliver packet to NextHop router else deliver packet to default router

13. Forwarding table for R2 NetworkNumNextHop 1R3 2R1 3Interface 1 4Interface 0

14. Local Delivery Address Translation Address Resolution Protocol (ARP) ARP request induces the target to broadcast its IP and Local address across the LAN. Requesting router then knows how to deliver the message Target keeps the senders local address and IP address in its own ARP table—in case it needs to ACK

16. Host Configuration Dynamic Host Configuration Protocol (DHCP) DHCP Server-assigns dynamic IP addresses New hosts broadcast DHCPDISCOVER message to 255.255.255.255-this message does not go to other networks Request may use a DHCP Relay Agent to reach a server on another network

19. Error Reporting Internet Control Message Protocol (ICMP) –Host unreachable –Reassembly failed –TTL=0 –IP header checksum failed –ICMP-Redirect

20. Virtual Private Network

21. Tunnel Concept

22. Forwarding table for router R1 NetworkNumNextHop 1Interface 0 2Virtual interface 0 DefaultInterface 1