Operation Manual – IPv6 RoutingH3C S5500-EI Series Ethernet Switches Chapter 2 IPv6 RIPng Configuration2-1Chapter 2 IPv6 RIPng ConfigurationNote:z The term “router” in this document refers to a Layer 3 switch running routingprotocols.z The S5500-EI series only support single RIPng process.2.1 Introduction to RIPngRIP next generation (RIPng) is an extension of RIP-2 for IPv4. Most RIP concepts areapplicable in RIPng.RIPng for IPv6 made the following changes to RIP:z UDP port number: RIPng uses UDP port 521 for sending and receiving routinginformation.z Multicast address: RIPng uses FF02:9 as the link-local multicast address.z Destination Prefix: 128-bit destination address prefix.z Next hop: 128-bit IPv6 address.z Source address: RIPng uses FE80::/10 as the link-local source address2.1.1 RIPng Working MechanismRIPng is a routing protocol based on the distance vector (D-V) algorithm. RIPng usesUDP packets to exchange routing information through port 521.RIPng uses a hop count to measure the distance to a destination. The hop count isreferred to as metric or cost. The hop count from a router to a directly connectednetwork is 0. The hop count between two directly connected routers is 1. When the hopcount is greater than or equal to 16, the destination network or host is unreachable.By default, the routing update is sent every 30 seconds. If the router receives no routingupdates from a neighbor after 180 seconds, the routes learned from the neighbor areconsidered as unreachable. After another 240 seconds, if no routing update is received,the router will remove these routes from the routing table.RIPng supports Split Horizon and Poison Reverse to prevent routing loops, and routeredistribution.Each RIPng router maintains a routing database, including route entries of allreachable destinations. A route entry contains the following information:
