RFC 2918 (rfc2918) - Page 1 of 4
Route Refresh Capability for BGP-4
Alternative Format: Original Text Document
Network Working Group E. Chen
Request for Comments: 2918 Redback Networks
Category: Standards Track September 2000
Route Refresh Capability for BGP-4
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2000). All Rights Reserved.
Abstract
This document defines a new Border Gateway Protocol (BGP) capability
termed 'Route Refresh Capability', which would allow the dynamic
exchange of route refresh request between BGP speakers and subsequent
re-advertisement of the respective Adj-RIB-Out. One possible
application of this capability is to facilitate non-disruptive
routing policy changes.
1. Introduction
Currently there does not exist a mechanism in BGP-4 [BGP-4] to
dynamically request a re-advertisement of the Adj-RIB-Out from a BGP
peer. When the inbound routing policy for a peer changes, all
prefixes from that peer must be somehow made available and then re-
examined against the new policy. To accomplish this, a commonly used
approach, known as 'soft-reconfiguration', is to store an unmodified
copy of all routes from that peer at all times, even though routing
policies do not change frequently (typically no more than a couple
times a day). Additional memory and CPU are required to maintain
these routes.
This document proposes an alternative solution that avoids the
additional maintenance cost. More specifically, it defines a new BGP
capability termed 'Route Refresh Capability', which would allow the
dynamic exchange of route refresh request between BGP speakers and
subsequent re-advertisement of the respective Adj-RIB-Out.
Chen Standards Track