RFC 2080 (rfc2080) - Page 2 of 19

RIPng for IPv6

RFC 2080                     RIPng for IPv6                 January 1997


   2.5   Output Processing  . . . . . . . . . . . . . . . . . . . . . 14
   2.5.1   Triggered Updates  . . . . . . . . . . . . . . . . . . . . 14
   2.5.2   Generating Response Messages . . . . . . . . . . . . . . . 15
   2.6   Split Horizon  . . . . . . . . . . . . . . . . . . . . . . . 16
   3.  Control Functions  . . . . . . . . . . . . . . . . . . . . . . 17
   4.  Security Considerations. . . . . . . . . . . . . . . . . . . . 18
   References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19

1. Introduction

   This memo describes one protocol in a series of routing protocols
   based on the Bellman-Ford (or distance vector) algorithm.  This
   algorithm has been used for routing computations in computer networks
   since the early days of the ARPANET.  The particular packet formats
   and protocol described here are based on the program "routed," which
   is included with the Berkeley distribution of Unix.

   In an international network, such as the Internet, it is very
   unlikely that a single routing protocol will used for the entire
   network.  Rather, the network will be organized as a collection of
   Autonomous Systems (AS), each of which will, in general, be
   administered by a single entity.  Each AS will have its own routing
   technology, which may differ among AS's.  The routing protocol used
   within an AS is referred to as an Interior Gateway Protocol (IGP).  A
   separate protocol, called an Exterior Gateway Protocol (EGP), is used
   to transfer routing information among the AS's.  RIPng was designed
   to work as an IGP in moderate-size AS's.  It is not intended for use
   in more complex environments.  For information on the context into
   which RIP version 1 (RIP-1) is expected to fit, see Braden and Postel
   [6].

   RIPng is one of a class of algorithms known as Distance Vector
   algorithms.  The earliest description of this class of algorithms
   known to the author is in Ford and Fulkerson [8].  Because of this,
   they are sometimes known as Ford-Fulkerson algorithms.  The term
   Bellman-Ford is also used, and derives from the fact that the
   formulation is based on Bellman's equation [4].  The presentation in
   this document is closely based on [5].  This document contains a
   protocol specification.  For an introduction to the mathematics of
   routing algorithms, see [1].  The basic algorithms used by this
   protocol were used in computer routing as early as 1969 in the
   ARPANET.  However, the specific ancestry of this protocol is within
   the Xerox network protocols.  The PUP protocols [7] used the Gateway
   Information Protocol to exchange routing information.  A somewhat
   updated version of this protocol was adopted for the Xerox Network
   Systems (XNS) architecture, with the name Routing Information
   Protocol [9].  Berkeley's routed is largely the same as the Routing



Malkin & Minnear            Standards Track