RIP versions

There are two RIP versions, RIPv1 and RIPv2.

RIPv1 is a classful routing protocol. It advertises messages through broadcast only. RIPv1 messages do not carry mask information, so RIPv1 can only recognize natural networks such as Class A, B, and C. For this reason, RIPv1 does not support discontiguous subnets.

RIPv2 is a classless routing protocol. It has the following advantages over RIPv1:

• Supports route tags to implement flexible route control through routing policies.

• Supports masks, route summarization, and CIDR.

• Supports designated next hops to select the best ones on broadcast networks.

• Supports multicasting route updates so only RIPv2 routers can receive these updates to reduce resource consumption.

• Supports plain text authentication and MD5 authentication to enhance security.

RIPv2 supports two transmission modes: broadcast and multicast. Multicast is the default mode using 224.0.0.9 as the multicast address. An interface operating in RIPv2 broadcast mode can also receive RIPv1 messages.