Although RIPv2 represents a significant improvement over the original version, RIPv2 is still a routing protocol used for IPv4 networks only. Because of this, a new version of RIP, referred to as RIPng or RIP version 3 has been developed in order to support this popular distance vector routing protocol on IPv6 networks. In case you’re curious, the “ng” in RIPng stands for “next generation”.
RIPng functions in a manner almost identical to RIPv2, though with a couple of key differences. The first is that instead of using IPv4 addresses in its update messages, RIPng uses IPv6 addresses and prefixes. The second change is that when a RIPng router needs to communicate with other RIPng routers, it uses a special multicast address (FF02::9) as the destination address.
As of this writing, RIPng was still not a finalized Internet standard. It is currently a proposed standard in the RFC process, but Cisco already supports the protocol in their IPv6 IOS images.