9

Routing

IPv6 did not change the fundamentals of IP routing. It is still based on:

• the longest prefix match;
• the possible use of source routing;
• redirects with ICMP;
• the same routing protocols: Routing Information Protocol (RIP), Open Shortest Path First (OSPF), Intermediate System to Intermediate System (IS-IS) and Border Gateway Protocol (BGP).

No major change in the routing means that a routing expert feels at home when dealing with IPv6 routing. However, there are some changes made to handle routing more efficiently or to make use of IPv6 facilities. This chapter describes these changes, starting with required router addresses, source routing and route redirection. It then presents the routing protocols: RIP, OSPF, IS-IS and BGP. Other topics related to routing such as router renumbering, multihoming and route aggregation are also discussed.