RFC 1268 (rfc1268) - Page 2 of 13


Application of the Border Gateway Protocol in the Internet



Alternative Format: Original Text Document



RFC 1268           Application of BGP in the Internet       October 1991


   jointly authored by Jeffrey C. Honig (Cornell University), Dave Katz
   (MERIT), Matt Mathis (PSC), Yakov Rekhter (IBM), and Jessica Yu
   (MERIT).

   The following also made key contributions to RFC 1164 -- Guy Almes
   (ANS, then at Rice University), Kirk Lougheed (cisco Systems), Hans-
   Werner Braun (SDSC, then at MERIT), and Sue Hares (MERIT).

   This updated version of the document is the product of the IETF BGP
   Working Group with Phillip Gross (ANS) and Yakov Rekhter (IBM) as
   editors.  John Moy (Proteon) contributed Section 6 "Recommended set
   of supported routing policies".

   We also like to explicitly thank Bob Braden (ISI) for the review of
   this document as well as his constructive and valuable comments.

1. Introduction

   This memo describes the use of the Border Gateway Protocol (BGP) [1]
   in the Internet environment. BGP is an inter-Autonomous System
   routing protocol. The network reachability information exchanged via
   BGP provides sufficient information to detect routing loops and
   enforce routing decisions based on performance preference and policy
   constraints as outlined in RFC 1104 [2]. In particular, BGP exchanges
   routing information containing full AS paths and enforces routing
   policies based on configuration information.

   All of the discussions in this paper are based on the assumption that
   the Internet is a collection of arbitrarily connected Autonomous
   Systems. That is, the Internet will be modeled as a general graph
   whose nodes are AS's and whose edges are connections between pairs of
   AS's.

   The classic definition of an Autonomous System is a set of routers
   under a single technical administration, using an interior gateway
   protocol and common metrics to route packets within the AS, and using
   an exterior gateway protocol to route packets to other AS's. Since
   this classic definition was developed, it has become common for a
   single AS to use several interior gateway protocols and sometimes
   several sets of metrics within an AS. The use of the term Autonomous
   System here stresses the fact that, even when multiple IGPs and
   metrics are used, the administration of an AS appears to other AS's
   to have a single coherent interior routing plan and presents a
   consistent picture of which networks are reachable through it. From
   the standpoint of exterior routing, an AS can be viewed as
   monolithic: networks within an AS must maintain connectivity via
   intra-AS paths.




BGP Working Group