Illustrated TCP/IP by Matthew G. Naugle Wiley Computer Publishing, John Wiley & Sons, Inc. ISBN: 0471196568   Pub Date: 11/01/98

Chapter 109
RIP Version 2

In November, 1994, RIP was modified with some additions (extensions) to overcome some of its shortcomings. RIP version 1 continues to exist on many routers and as of this writing, continues to outnumber OSPF networks. However, there is no reason not to implement version 2 of the protocol. Version 2 is backward compatible with version 1 and contains all of the capabilities of the version 1 protocol.

RIP version 2 implemented the following features:

•  Authentication—simple text password

•  Subnet masking

•  Next host

•  Multicast—to allow for variable-length subnet masks to be implemented

•  Route tag—to provide a method of separating RIP routes from externally learned routes

•  Compatibility switch—to allow for interoperability with version 1 routers

Notice that the same format is used for RIPv1 and RIPv2. Apparently, there was some thought when building RIPv1 that future protocols of RIP may be different and that more information is to be carried in the packet. The original packet indicated that the field must be set to 0, and not reserved. Now you can see why. If not, we will revisit this in the subnet mask topic of this section.

RIP Version 2