CSE 123 Lecture Notes - Lecture 9: Ipv4, Packet Loss, Checksum
17 Oct 2018
School
Department
Course
Professor
Document Summary
Own addressing scheme (for routers to forward packets) E. g: fddi"s max packet is 4500 bytes while ethernet is 1500 bytes! Something might go wrong in the last hop. Does not worry about packet loss, duplication, reassembling, or retransmitting packets! Only allow hl to be a multiple of word (4 bytes) We know how to incrementally modify the checksum in a very straightforward manner. Most link layers cannot accommodate an mtu of 64k! If it doesn"t pass, just drop the packet! Which transport protocol is the data using? (what"s up?) How should a host interpret the data. Up to router to respect this request! Router discards packet when ttl = 0. Internet is designed to now grow more than 255 hops! Diameter is actually only around 30 hops! End host reassembles them into original packet. Fragmentation - different networks may have different max frame sizes. Router breaks up single ip packet into 2 or smaller ip packets.
