RFC 3345 (rfc3345) - Page 1 of 19
Border Gateway Protocol (BGP) Persistent Route Oscillation Condition
Alternative Format: Original Text Document
Network Working Group D. McPherson
Request for Comments: 3345 TCB
Category: Informational V. Gill
AOL Time Warner, Inc.
D. Walton
A. Retana
Cisco Systems, Inc.
August 2002
Border Gateway Protocol (BGP) Persistent Route Oscillation Condition
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 (2002). All Rights Reserved.
Abstract
In particular configurations, the BGP scaling mechanisms defined in
"BGP Route Reflection - An Alternative to Full Mesh IBGP" and
"Autonomous System Confederations for BGP" will introduce persistent
BGP route oscillation. This document discusses the two types of
persistent route oscillation that have been identified, describes
when these conditions will occur, and provides some network design
guidelines to avoid introducing such occurrences.
1. Introduction
The Border Gateway Protocol (BGP) is an inter-Autonomous System
routing protocol. The primary function of a BGP speaking system is
to exchange network reachability information with other BGP systems.
In particular configurations, the BGP [1] scaling mechanisms defined
in "BGP Route Reflection - An Alternative to Full Mesh IBGP" [2] and
"Autonomous System Confederations for BGP" [3] will introduce
persistent BGP route oscillation.
The problem is inherent in the way BGP works: locally defined routing
policies may conflict globally, and certain types of conflicts can
cause persistent oscillation of the protocol. Given current
practices, we happen to see the problem manifest itself in the
context of MED + route reflectors or confederations.
McPherson, et al. Informational