RFC 3765 (rfc3765) - Page 1 of 7

NOPEER Community for Border Gateway Protocol (BGP) Route Scope Control

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Network Working Group                                          G. Huston
Request for Comments: 3765                                       Telstra
Category: Informational                                       April 2004


           NOPEER Community for Border Gateway Protocol (BGP)
                          Route Scope Control

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2004).  All Rights Reserved.

Abstract

   This document describes the use of a scope control Border Gateway
   Protocol (BGP) community.  This well-known advisory transitive
   community allows an origin AS to specify the extent to which a
   specific route should be externally propagated.  In particular this
   community, NOPEER, allows an origin AS to specify that a route with
   this attribute need not be advertised across bilateral peer
   connections.

1.  Introduction

   BGP today has a limited number of commonly defined mechanisms that
   allow a route to be propagated across some subset of the routing
   system.  The NOEXPORT community allows a BGP speaker to specify that
   redistribution should extend only to the neighbouring AS.  Providers
   commonly define a number of communities that allow their neighbours
   to specify how advertised routes should be re-advertised.  Current
   operational practice is that such communities are defined on as AS by
   AS basis, and while they allow an AS to influence the re-
   advertisement behaviour of routes passed from a neighbouring AS, they
   do not allow this scope definition ability to be passed in a
   transitive fashion to a remote AS.

   Advertisement scope specification is of most use in specifying the
   boundary conditions of route propagation.  The specification can take
   on a number of forms, including as AS transit hop count, a set of
   target ASs, the presence of a particular route object, or a
   particular characteristic of the inter-AS connection.




Huston                       Informational
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