Posted: August 18th, 2016

Briefly describe what information is contained in the updated information routers receive, where the information comes from, and why it is considered “second hand” or “first hand”

Both RIPv2 and OSPFv2 routing protocols receive updated information about the state of the network from their neighbours. However it can be said that the decisions made by vector-distance routing protocols (such as RIPV2) are based on “second hand” information, whilst the decisions made by link state routing protocols (OSPFv2) is based on “first hand” information. Briefly describe what information is contained in the updated information routers receive, where the information comes from, and why it is considered “second hand” or “first hand”. b) Given the following Link State Database and network topology: A B C D E F A C E F B D A – – 1 – 4 1 B – – – 3 1 6 C 1 – – – 2 – D – 3 – – – 2 E 4 1 2 – – – F 1 6 – 2 – – Demonstrate the working of the Shortest Path First algorithm and final routing table. Your answer must indicate the paths and costs that will be taken by all datagrams through the network. c) For each of the fields listed below appearing in the IPv4 and IPv6 headers, briefly describe the purpose of those fields, explain how they are related, and explain why a change has been made: i. IPv4 defines both header length (HLEN) and total length fields, whilst IPv6 defines only a payload length. ii. IPv4 defines a protocol field, whilst IPv6 defines a next header field. iii. IPv4 defines a time to live (TTL) field, whilst IPv6 defines a hop limit field.