draft-ietf-idr-bgp-identifier-14.txt   rfc6286.txt 
Network Working Group E. Chen Internet Engineering Task Force (IETF) E. Chen
Internet Draft J. Yuan Request for Comments: 6286 J. Yuan
Intended Status: Standards Track Cisco Systems Updates: 4271 Cisco Systems
Updates: RFC 4271 May 4, 2011 Category: Standards Track June 2011
Expiration Date: November 5, 2011 ISSN: 2070-1721
AS-wide Unique BGP Identifier for BGP-4
draft-ietf-idr-bgp-identifier-14.txt
Status of this Memo Autonomous-System-Wide Unique BGP Identifier for BGP-4
This Internet-Draft is submitted to IETF in full conformance with the Abstract
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering To accommodate situations where the current requirements for the BGP
Task Force (IETF), its areas, and its working groups. Note that Identifier are not met, this document relaxes the definition of the
other groups may also distribute working documents as Internet- BGP Identifier to be a 4-octet, unsigned, non-zero integer and
Drafts. relaxes the "uniqueness" requirement so that only Autonomous-System-
wide (AS-wide) uniqueness of the BGP Identifiers is required. These
revisions to the base BGP specification do not introduce any backward
compatibility issues. This document updates RFC 4271.
Internet-Drafts are draft documents valid for a maximum of six months Status of This Memo
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at This is an Internet Standards Track document.
http://www.ietf.org/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at This document is a product of the Internet Engineering Task Force
http://www.ietf.org/shadow.html (IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
This Internet-Draft will expire on November 5, 2011. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6286.
Copyright Notice Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Abstract 1. Introduction
To accommodate situations where the current requirements for the BGP
Identifier are not met, this document relaxes the definition of the
BGP Identifier to be a 4-octet unsigned, non-zero integer, and
relaxes the "uniqueness" requirement so that only AS-wide uniqueness
of the BGP Identifiers is required. These revisions to the base BGP
specification do not introduce any backward compatibility issue.
1. Introduction
Currently the BGP Identifier of a BGP speaker is specified as a valid Currently, the BGP Identifier of a BGP speaker is specified as a
IPv4 host address assigned to the BGP speaker [RFC4271]. In valid IPv4 host address assigned to the BGP speaker [RFC4271]. In
addition, the deployed BGP code requires that two BGP speakers be of addition, the deployed BGP code requires that two BGP speakers be of
distinct BGP Identifiers in order to establish a BGP connection. distinct BGP Identifiers in order to establish a BGP connection.
To accommodate situations where the current requirements for the BGP To accommodate situations where the current requirements for the BGP
Identifier are not met (such as in the case of an IPv6-only network), Identifier are not met (such as in the case of an IPv6-only network),
this document relaxes the definition of the BGP Identifier to be a this document relaxes the definition of the BGP Identifier to be a
4-octet unsigned, non-zero integer, and relaxes the "uniqueness" 4-octet, unsigned, non-zero integer and relaxes the "uniqueness"
requirement so that only AS-wide uniqueness of the BGP Identifiers is requirement so that only AS-wide uniqueness of the BGP Identifiers is
required. These revisions to the base BGP specification do not required. These revisions to the base BGP specification do not
introduce any backward compatibility issue. introduce any backward compatibility issues.
2. Protocol Revisions 2. Protocol Revisions
The revisions to the base BGP specification [RFC4271] include the The revisions to the base BGP specification [RFC4271] include the
definition of the BGP Identifier and procedures for a BGP speaker definition of the BGP Identifier and procedures for a BGP speaker
that supports the AS-wide Unique BGP Identifier. that supports the AS-wide Unique BGP Identifier.
2.1. Definition of the BGP Identifier 2.1. Definition of the BGP Identifier
For a BGP speaker that supports the AS-wide Unique BGP Identifier, For a BGP speaker that supports the AS-wide Unique BGP Identifier,
the BGP Identifier is specified as the following: the BGP Identifier is specified as the following:
The BGP Identifier is a 4-octet unsigned, non-zero integer that The BGP Identifier is a 4-octet, unsigned, non-zero integer that
should be unique within an AS. The value of the BGP Identifier for should be unique within an AS. The value of the BGP Identifier
a BGP speaker is determined on startup and is the same for every for a BGP speaker is determined on startup and is the same for
local interface and every BGP peer. every local interface and every BGP peer.
2.2. Open Message Error Handling 2.2. Open Message Error Handling
For a BGP speaker that supports the AS-wide Unique BGP Identifier, For a BGP speaker that supports the AS-wide Unique BGP Identifier,
the OPEN message error handling related to the BGP Identifier is the OPEN message error handling related to the BGP Identifier is
modified as follows: modified as follows:
If the BGP Identifier field of the OPEN message is zero, or if If the BGP Identifier field of the OPEN message is zero, or if it
it is the same as the BGP Identifier of the local BGP speaker is the same as the BGP Identifier of the local BGP speaker and the
and the message is from an internal peer, then the Error Subcode message is from an internal peer, then the Error Subcode is set to
is set to "Bad BGP Identifier". "Bad BGP Identifier".
2.3. Connection Collision Resolution 2.3. Connection Collision Resolution
For a BGP speaker that supports the AS-wide Unique BGP Identifier, For a BGP speaker that supports the AS-wide Unique BGP Identifier,
the procedures for connection collision resolution are extended as the procedures for connection collision resolution are extended as
follows to deal with the case in which the two BGP speakers share the follows to deal with the case in which the two BGP speakers share the
same BGP Identifier (thus it is only applicable to an external peer): same BGP Identifier (thus, it is only applicable to an external
peer):
If the BGP Identifiers of the peers involved in the connection If the BGP Identifiers of the peers involved in the connection
collision are identical, then the connection initiated by the BGP collision are identical, then the connection initiated by the BGP
speaker with the larger AS number is preserved. speaker with the larger AS number is preserved.
This extension covers cases in which the four-octet AS numbers are This extension covers cases in which the 4-octet AS numbers are
involved [RFC4893]. involved [RFC4893].
3. Remarks 3. Remarks
It is noted that a BGP Identifier allocated based on [RFC4271] fits It is noted that a BGP Identifier allocated based on [RFC4271] fits
the revised definition. the revised definition.
In case of BGP Confederation, the whole confederation is considered In case of BGP Confederation, the whole confederation is considered
as one AS for the purpose of supporting the AS-wide Unique BGP as one AS for the purpose of supporting the AS-wide Unique BGP
Identifier. Identifier.
A BGP speaker that supports the AS-wide Unique BGP Identifier can not A BGP speaker that supports the AS-wide Unique BGP Identifier cannot
share a BGP Identifier with its external neighbor until the remote share a BGP Identifier with its external neighbor until the remote
BGP speaker is upgraded with software that supports the specified BGP speaker is upgraded with software that supports the specified
revisions. revisions.
In addition to the OPEN message, the BGP Identifier is currently also In addition to the OPEN message, the BGP Identifier is currently also
used in the following areas: used in the following areas:
o In the AGGREAGTOR attribute of a route where the combination of o In the AGGREAGTOR attribute of a route where the combination of a
a BGP Identifier and an AS number uniquely identifies the BGP BGP Identifier and an AS number uniquely identifies the BGP speaker
speaker that performs the route aggregation. that performs the route aggregation.
o In the Route Reflection within an AS, where only the BGP o In the Route Reflection within an AS, where only the BGP Identifier
Identifier of an internal neighbor may be propagated in the of an internal neighbor may be propagated in the route reflection
route reflection related attributes. related attributes.
o In the route selection, where the BGP Identifier is not used o In the route selection, where the BGP Identifier is not used in
in comparing a route from an internal neighbor and a route from comparing a route from an internal neighbor and a route from an
an external neighbor. In addition, routes from BGP speakers with external neighbor. In addition, routes from BGP speakers with
identical BGP Identifiers have been dealt with (e.g., parallel identical BGP Identifiers have been dealt with (e.g., parallel BGP
BGP sessions between two BGP speakers). sessions between two BGP speakers).
Therefore it is concluded that the revisions specified in this Therefore, it is concluded that the revisions specified in this
document do not introduce any backward compatibility issue with the document do not introduce any backward compatibility issues with the
current usage of the BGP Identifier. current usage of the BGP Identifier.
4. Security Considerations 4. Security Considerations
This extension to BGP does not introduce new security considerations. This extension to BGP does not introduce new security considerations.
BGP security considerations are discussed in [RFC4271]. BGP security considerations are discussed in [RFC4271].
5. IANA Considerations 5. Acknowledgments
This document has no actions for IANA.
6. Acknowledgments
The authors would like to thank members of the IDR Working Group for The authors would like to thank members of the IDR Working Group for
discussions on the "IPv6-only Network" related issues that inspired discussions on the "IPv6-only Network" related issues that inspired
this document. this document.
7. Normative References 6. Normative References
[RFC4271] Rekhter, Y., T. Li, and S. Hares, "A Border Gateway [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A Border
Protocol 4 (BGP-4)", RFC 4271, January 2006. Gateway Protocol 4 (BGP-4)", RFC 4271, January 2006.
[RFC4893] Vohra, Q., and E. Chen, "BGP Support for Four-octet AS [RFC4893] Vohra, Q. and E. Chen, "BGP Support for Four-octet AS
Number Space", RFC 4893, May 2007. Number Space", RFC 4893, May 2007.
8. Authors' Addresses Authors' Addresses
Enke Chen Enke Chen
Cisco Systems, Inc. Cisco Systems, Inc.
170 W. Tasman Dr. 170 W. Tasman Dr.
San Jose, CA 95134 San Jose, CA 95134
EMail: enkechen@cisco.com EMail: enkechen@cisco.com
Jenny Yuan Jenny Yuan
Cisco Systems, Inc. Cisco Systems, Inc.
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