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Network Working Group                                          G. MalkinRequest for Comments: 1387                                Xylogics, Inc.                                                            January 1993RIP Version 2 Protocol AnalysisStatus of this Memo   This memo provides information for the Internet community.  It does   not specify an Internet standard.  Distribution of this memo is   unlimited.Abstract   As required by Routing Protocol Criteria (RFC 1264), this report   documents the key features of the RIP-2 protocol and the current   implementation experience.Acknowledgements   The RIP-2 protocol owes much to those who participated in the RIP-2   Working Group of the Internet Engineering Task Force (IETF).  A   special thanks goes to Fred Baker for his help on the MIB, and to   Jeffrey Honig for the implementation experience.1.  Protocol Documents   The RIP-2 protocol description is defined inRFC 1388 [1].  This memo   suggests an update to the "Routing Information Protocol" (RFC 1058)   [3].  The RIP-2 MIB description is defined inRFC 1389 [2].2.  Key Features   While RIP-2 shares the same basic algorithms as RIP-1, it supports   several new features.  They are: routing domains, external route   tags, subnet masks, next hop addresses, and authentication.2.1  Routing Domains   Routing domains allow multiple RIP "clouds" to exist over the same   physical network.  This is a feature requested by several members of   the working group.  It allows simple policies to be constructed by   grouping routers into domains which share routing information.Malkin                                                          [Page 1]

RFC 1387                     RIP-2 Analysis                 January 19932.2  External Route Tags   The route tag field may be used to propagate information acquired   from an EGP.  The definition of the contents of this field are beyond   the scope of this protocol.  However, it may be used, for example, to   propagate an EGP AS number.2.3  Subnet Masks   Inclusion of subnet masks was the original intent of opening the RIP   protocol for improvement.  Subnet mask information makes RIP more   useful in a variety of environments and allows the use of variable   subnet masks on the network.  Subnet masks are also necessary for   implementation of "classless" addressing, as the CIDR work proposes.2.4  Next Hop Addresses   Support for next hop addresses allows for optimization of routes in   an environment which uses multiple routing protocols.  For example,   if RIP-2 were being run on a network along with another IGP, and one   router ran both protocols, then that router could indicate to the   other RIP-2 routers that a better next hop than itself exists for a   given destination.2.5  Authentication   One significant improvement RIP-2 offers over RIP-1, is the addition   of an authentication mechanism.  Essentially, it is the same   extensible mechanism provided by OSPF.  Currently, only a plain-text   password is defined for authentication.  However, more sophisticated   authentication schemes can easily be incorporated as they are   defined.2.6  Multicasting   RIP-2 packets may be multicast instead of being broadcast.  The use   of an IP multicast address reduces the load on hosts which do not   support routing protocols.  It also allows RIP-2 routers to share   information which RIP-1 routers cannot hear.  This is useful since a   RIP-1 router may misinterpret route information because it cannot   apply the supplied subnet mask.3.  RIP-2 MIB   The MIB for RIP-2 allows for monitoring and control of RIP's   operation within the router.  In addition to global and per-interface   counters and controls, there is are per-peer counters which provide   the status of RIP-2 "neighbors".Malkin                                                          [Page 2]

RFC 1387                     RIP-2 Analysis                 January 19934.  Implementations   Currently, there is one nearly complete implementation of RIP-2.  A   "gated" implementation is now available with RIP-2, written by   Jeffrey Honig at Cornell University.  It may be acquired by anonymous   FTP from gated.cornell.edu as pub/gated/gated-alpha.tar.Z.  It   implements multicasting, subnet masks, limited authentication, next-   hop, and limited routing domain support.  A RIP-2 version of ripquery   is also available.  The "gated" implementation does not yet support   full subsumption rules, full authentication, full routing domains,   and the MIB.  It has been tested against itself and various RIP-1   implementations.   A second, complete implementation is under development by a vendor   who's identity cannot be disclosed at this time.5. References   [1] Malkin, G., "RIP Version 2 - Carrying Additional Information",RFC 1388, Xylogics, Inc., January 1993.   [2] Malkin, G., and F. Baker, "RIP Version 2 MIB Extension",RFC1389, Xylogics, Inc., Advanced Computer Communications, January       1993.   [3] Hedrick, C., "Routing Information Protocol",RFC 1058, Rutgers       University, June 1988.6.  Security Considerations       Security issues are discussed insection 2.5.7.  Author's Address       Gary Scott Malkin       Xylogics, Inc.       53 Third Avenue       Burlington, MA 01803       Phone:  (617) 272-8140       EMail:  gmalkin@Xylogics.COMMalkin                                                          [Page 3]