The Routing Information Protocol (RIP) was a first generation routing protocol for IPv4 originally specified in RFC 1058. It is easy to configure, making it a good choice for small networks.

RIPv1 has the following key characteristics:

In 1993, RIPv1 evolved to a classless routing protocol known as RIP version 2 (RIPv2). RIPv2 introduced the following improvements:

The table in the figure summarizes the differences between RIPv1 and RIPv2.

RIP updates are encapsulated into a UDP segment, with both source and destination port numbers set to UDP port 520.

In 1997, the IPv6 enabled version of RIP was released. RIPng is based on RIPv2. It still has a 15 hop limitation and the administrative distance is 120.