IP FORWARDING Dr. Rocky K C Chang 1 1 October 2010
IP FORWARDING Dr. Rocky K. C. Chang 11 October 2010 1
Content 口 Switches vs routers a The iP forwarding problem n The IP address lookup problem 口| P tunneling a Forwarding-related ICMP messages
Content 2 Switches vs routers The IP forwarding problem The IP address lookup problem IP tunneling Forwarding-related ICMP messages
Routers vs switches 3 a Price/performance comparison o Besides packet forwarding, routers offer rich functionalities n Support multiple network-layer protocols a block broadcast packets a Provide type-of-service routing(differentiated service) a Perform admission control, per-flow queueing, resource reservation, and fair scheduling n Assist in network congestion control. 口 Support tunneling a Support IP fragmentation Perform nat a etc
Routers vs switches 3 Price/performance comparison Besides packet forwarding, routers offer rich functionalities: Support multiple network-layer protocols. Block broadcast packets. Provide type-of-service routing (differentiated service). Perform admission control, per-flow queueing, resource reservation, and fair scheduling. Assist in network congestion control. Support tunneling Support IP fragmentation Perform NAT etc
Things that a router needs to worry about a Integrity of an incoming packet Checksum for the header a Source address spoofing(limited) a Receiving: queueing, scheduling, detunneling, etc o Dropping or forwarding a Dropping (TTL, broadcasting, congestion, and the integrity issues)and feedback n Forwarding: destination address (and perhaps source addresses and interface), and Tos 口 Forwarding a Fragmentation, tunneling, source address and port translation
Things that a router needs to worry about 4 Integrity of an incoming packet: Checksum for the header Source address spoofing (limited) Receiving: queueing, scheduling, detunneling, etc Dropping or forwarding Dropping (TTL, broadcasting, congestion, and the integrity issues) and feedback Forwarding: destination address (and perhaps source addresses and interface), and TOS. Forwarding Fragmentation, tunneling, source address and port translation
5P forwarding
5 IP forwarding