Autonomous System Confederations for BGP (RFC3065)
Original Publication Date: 2001-Feb-01
Included in the Prior Art Database: 2019-Feb-14
Internet Society Requests For Comment (RFCs)
P. Traina: AUTHOR [+2]
This document describes an extension to BGP which may be used to create a confederation of autonomous systems that is represented as a single autonomous system to BGP peers external to the confederation, thereby removing the "full mesh" requirement. The intention of this extension is to aid in policy administration and reduce the management complexity of maintaining a large autonomous system. [STANDARDS-TRACK]
Network Working Group P. Traina Request for Comments: 3065 Juniper Networks, Inc. Obsoletes: 1965 D. McPherson Category: Standards Track Amber Networks, Inc. J. Scudder Cisco Systems, Inc. February 2001
Autonomous System Confederations for BGP
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 (C) The Internet Society (2001). All Rights Reserved.
The Border Gateway Protocol (BGP) is an inter-autonomous system routing protocol designed for Transmission Control Protocol/Internet Protocol (TCP/IP) networks. BGP requires that all BGP speakers within a single autonomous system (AS) must be fully meshed. This represents a serious scaling problem that has been well documented in a number of proposals.
This document describes an extension to BGP which may be used to create a confederation of autonomous systems that is represented as a single autonomous system to BGP peers external to the confederation, thereby removing the "full mesh" requirement. The intention of this extension is to aid in policy administration and reduce the management complexity of maintaining a large autonomous system.
1. Specification of Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC 2119].
Traina, et al. Standards Track [Page 1]
RFC 3065 Autonomous System Confederations for BGP February 2001
As currently defined, BGP requires that all BGP speakers within a single AS must be fully meshed. The result is that for n BGP speakers within an AS n*(n-1)/2 unique IBGP sessions are required. This "full mesh" requirement clearly does not scale when there are a large number of IBGP speakers within the autonomous system, as is common in many networks today.
This scaling problem has been well documented and a number of proposals have been made to alleviate this [3,5]. This document represents another alternative in alleviating the need for a "full mesh" and is known as "Autonomous System Confederations for BGP", or simply, "BGP Confederations". It can also be said the BGP Confederations MAY provide improvements in routing policy control.
This document is a revision of RFC 1965  and it includes editorial changes, clarifications and corrections based on the deployment experience with BGP Confederations. These revisions are summarized in Appendix A.
3. Terms and Definitions
A collection of autonomous systems advertised as a single AS number to BGP speakers that are not members of the confederation.
AS Confederation Identifier
An externally visible autonomous system number...