RIP (Routing Information Protocol) is a Distance-Vector routing protocol which uses hop count as its metric. There are three versions or RIP, RIPv1, RIPv2 and RIPng.
RIPv1 was defined in RFC 1058. It is a classful protocol. It uses Broadcast messages for hellos/updates, the default hello timer is 30 seconds. RIPv1 does not support authentication. Due to these limitations, RIPv1 is not an ideal choice for use in current networks.
RIPv2, defined in RFC 2453, was modified to support many of the features which were deemed lacking in RIPv1. Some of these added features are:
- CIDR (classless) support
- Multicast updates (126.96.36.199)
- Support for triggered updates
RIPng, defined in RFC 2080, is a version of RIP which was modified to support IPv6.
RIP uses hop count as its metric. It has a limitation of 15 hops for reachability. By default, a router will not use a path if it is over 15 hops away.
router rip version 2 no auto-summary network 10.0.0.0 network 172.30.0.0 ! interface fa0/0 ip address 10.1.1.1 255.255.255.0 ! interface fa0/1 ip address 172.30.0.1 255.255.255.0