RFC 2519 (rfc2519) - Page 1 of 13

A Framework for Inter-Domain Route Aggregation

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Network Working Group                                            E. Chen
Request for Comments: 2519                                         Cisco
Category: Informational                                       J. Stewart
                                                                 Juniper
                                                           February 1999


             A Framework for Inter-Domain Route Aggregation

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 (1999).  All Rights Reserved.

Abstract

   This document presents a framework for inter-domain route aggregation
   and shows an example router configuration which 'implements' this
   framework.  This framework is flexible and scales well as it
   emphasizes the philosophy of aggregation by the source, both within
   routing domains as well as towards upstream providers, and it also
   strongly encourages the use of the 'no-export' BGP community to
   balance the provider-subscriber need for more granular routing
   information with the Internet's need for scalable inter-domain
   routing.

1. Introduction

   The need for route aggregation has long been recognized.  Route
   aggregation is good as it reduces the size, and slows the growth, of
   the Internet routing table.  Thus, the amount of resources (e.g., CPU
   and memory) required to process routing information is reduced and
   route calculation is sped up.  Another benefit of route aggregation
   is that route flaps are limited in number, frequency and scope, which
   saves resources and makes the global Internet routing system more
   stable.

   Since CIDR (Classless Inter-Domain Routing) [2] was introduced,
   significant progress has been made on route aggregation, particularly
   in the following two areas:

      - Formulation and implementation of IP address allocation policies
        by the top registries that conform to the CIDR principles [1].



Chen & Stewart               Informational
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