Overview
RIPng is a distance vector routing protocol. It employs UDP to exchange route information through port 521. RIPng uses a hop count to measure the distance to a destination. The hop count is the metric or cost. The hop count from a router to a directly connected network is 0. The hop count between two directly connected routers is 1. When the hop count 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 routing updates from a neighbor within 180 seconds, the routes learned from the neighbor are considered unreachable. If no routing update is received within another 240 seconds, the router removes these routes from the routing table.
RIPng for IPv6 has the following differences from RIP:
UDP port number—RIPng uses UDP port 521 to send and receive routing information.
Multicast address—RIPng uses FF02::9 as the link-local-router multicast address.
Destination Prefix—128-bit destination address prefix.
Next hop—128-bit IPv6 address.
Source address—RIPng uses FE80::/10 as the link-local source address.