RFC 1723 (rfc1723) - Page 2 of 9

RIP Version 2 - Carrying Additional Information

RFC 1723                     RIP Version 2                 November 1994


Table of Contents

   1.  Justification . . . . . . . . . . . . . . . . . . . . . . . . . 2
   2.  Current RIP . . . . . . . . . . . . . . . . . . . . . . . . . . 2
   3.  Protocol Extensions . . . . . . . . . . . . . . . . . . . . . . 3
   3.1   Authentication  . . . . . . . . . . . . . . . . . . . . . . . 4
   3.2   Route Tag . . . . . . . . . . . . . . . . . . . . . . . . . . 4
   3.3   Subnet Mask . . . . . . . . . . . . . . . . . . . . . . . . . 5
   3.4   Next Hop  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
   3.5   Multicasting  . . . . . . . . . . . . . . . . . . . . . . . . 5
   3.6   Queries . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
   4.  Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . 6
   4.1   Compatibility Switch  . . . . . . . . . . . . . . . . . . . . 6
   4.2   Authentication  . . . . . . . . . . . . . . . . . . . . . . . 6
   4.3   Larger Infinity . . . . . . . . . . . . . . . . . . . . . . . 7
   4.4   Addressless Links . . . . . . . . . . . . . . . . . . . . . . 7
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 7
   Appendix A  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
   References  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 9

1. Justification

   With the advent of OSPF and IS-IS, there are those who believe that
   RIP is obsolete.  While it is true that the newer IGP routing
   protocols are far superior to RIP, RIP does have some advantages.
   Primarily, in a small network, RIP has very little overhead in terms
   of bandwidth used and configuration and management time.  RIP is also
   very easy to implement, especially in relation to the newer IGPs.

   Additionally, there are many, many more RIP implementations in the
   field than OSPF and IS-IS combined.  It is likely to remain that way
   for some years yet.

   Given that RIP will be useful in many environments for some period of
   time, it is reasonable to increase RIP's usefulness.  This is
   especially true since the gain is far greater than the expense of the
   change.

2. Current RIP

   The current RIP message contains the minimal amount of information
   necessary for routers to route messages through a network.  It also
   contains a large amount of unused space, owing to its origins.

   The current RIP protocol does not consider autonomous systems and
   IGP/EGP interactions, subnetting, and authentication since
   implementations of these postdate RIP.  The lack of subnet masks is a



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