The Routing Information Protocol (RIP) has been in widespread use for over two decades. During that time, internetworks and internetworking technologies have changed. To keep up with the times, RIP has also evolved, and today has three different versions. The basic operation of all three is fairly similar, and was therefore described in the common section on concepts and operation. As you might expect, there are also some differences between the versions (or we wouldn't need versions!) One of the more important of these is the format used for RIP messages in each version, and the meaning and use of the fields within that format.

In this section I describe the message format used by each of the three versions of RIP, as well as certain specific features not common to all versions. I begin with the original RIP, also now known as RIP Version 1. I then describe the updated version of RIP called RIP Version 2 or RIP-2. Finally, I discuss RIPng, also sometimes called RIPv6, the version of RIP used for IP version 6 (IPv6). (Note that this is not technically a new version of the original RIP protocol but a new protocol closely based on RIP versions 1 and 2.