draft-ietf-idr-bgp-identifier-05.txt   draft-ietf-idr-bgp-identifier-06.txt 
Network Working Group Enke Chen Network Working Group Enke Chen
Internet Draft Jenny Yuan Internet Draft Jenny Yuan
Expiration Date: October 2005 Cisco Systems Expiration Date: May 2006 Cisco Systems
AS-wide Unique BGP Identifier for BGP-4 AS-wide Unique BGP Identifier for BGP-4
draft-ietf-idr-bgp-identifier-05.txt draft-ietf-idr-bgp-identifier-06.txt
1. Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
2. Abstract Abstract
To accommodate situations where the current requirements for the BGP To accommodate situations where the current requirements for the BGP
Identifier are not met, this document relaxes the definition of the Identifier are not met, this document relaxes the definition of the
BGP Identifier to be a 4-octet unsigned, non-zero integer, and BGP Identifier to be a 4-octet unsigned, non-zero integer, and
relaxes the "uniqueness" requirement so that only AS-wide uniqueness relaxes the "uniqueness" requirement so that only AS-wide uniqueness
of the BGP Identifiers is required. These revisions to the base BGP of the BGP Identifiers is required. These revisions to the base BGP
specification do not introduce any backward compatibility issue. specification do not introduce any backward compatibility issue.
3. Introduction 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 valid
IPv4 host address assigned to the BGP speaker [BGP-4]. In addition, IPv4 host address assigned to the BGP speaker [BGP-4]. In addition,
the deployed BGP code requires that two BGP speakers be of distinct the deployed BGP code requires that two BGP speakers be of distinct
BGP Identifiers in order to establish a BGP connection. 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, this document relaxes the definition of the Identifier are not met, this document relaxes the definition of the
BGP Identifier to be a 4-octet unsigned, non-zero integer, and BGP Identifier to be a 4-octet unsigned, non-zero integer, and
relaxes the "uniqueness" requirement so that only AS-wide uniqueness relaxes the "uniqueness" requirement so that only AS-wide uniqueness
of the BGP Identifiers is required. These revisions to the base BGP of the BGP Identifiers is required. These revisions to the base BGP
specification do not introduce any backward compatibility issue. specification do not introduce any backward compatibility issue.
4. Protocol Revisions 2. Protocol Revisions
The revisions to the base BGP specification [BGP-4] include the The revisions to the base BGP specification [BGP-4] 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.
4.1. 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 for
a BGP speaker is determined on startup and is the same for every a BGP speaker is determined on startup and is the same for every
local interface and every BGP peer. local interface and every BGP peer.
4.2. 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 is the same as the BGP Identifier of the local BGP speaker it is the same as the BGP Identifier of the local BGP speaker
and the message is from an internal peer, then the Error Subcode and the message is from an internal peer, then the Error Subcode
is set to "Bad BGP Identifier". is set to "Bad BGP Identifier".
4.3. 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 four-octet AS numbers are
involved [BGP-4BYTE-AS]. involved [BGP-4BYTE-AS].
5. Remarks 3. Remarks
It is noted that a BGP Identifier allocated based on [BGP-4] fits the It is noted that a BGP Identifier allocated based on [BGP-4] fits the
revised definition. 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 can not
share a BGP Identifier with its external neighbor until the remote share a BGP Identifier with its external neighbor until the remote
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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 comparing a route from an internal neighbor and a route from in comparing a route from an internal neighbor and a route from
an external neighbor. In addition, routes from BGP speakers with an 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 sessions between two BGP speakers). BGP sessions between two BGP speakers).
Therefore it is concluded that the revisions proposed in this Therefore it is concluded that the revisions proposed in this
document do not introduce any backward compatibility issue with the document do not introduce any backward compatibility issue with the
current usage of the BGP Identifier. current usage of the BGP Identifier.
6. Security Considerations 4. Security Considerations
This extension to BGP does not change the underlying security issues. This extension to BGP does not change the underlying security issues.
7. Acknowledgments 5. 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.
8. References 6. References
[BGP-4] Y. Rekhter, T. Li, and S. Hares "A Border Gateway Protocol 4 [BGP-4] Y. Rekhter, T. Li, and S. Hares "A Border Gateway Protocol 4
(BGP-4)", draft-ietf-idr-bgp4-26.txt, October 2004. (BGP-4)", draft-ietf-idr-bgp4-26.txt, October 2004.
[BGP-4BYTE-AS] Q. Vohra, E. Chen, "BGP support for four-octet AS [BGP-4BYTE-AS] Q. Vohra, E. Chen, "BGP Support for Four-octet AS
number space", Work in Progress, <draft-ietf-idr-as4bytes-09.txt>, Number Space", Work in Progress, <draft-ietf-idr-as4bytes-12.txt>,
December 2004. November 2005.
9. Author Information 7. Author Information
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
e-mail: enkechen@cisco.com
Email: enkechen@cisco.com
Jenny Yuan Jenny Yuan
Cisco Systems, Inc. Cisco Systems, Inc.
170 W. Tasman Dr. 170 W. Tasman Dr.
San Jose, CA 95134 San Jose, CA 95134
e-mail: jenny@cisco.com
10. Full Copyright Notice Email: jenny@cisco.com
8. Full Copyright Notice
Copyright (C) The Internet Society (2005). Copyright (C) The Internet Society (2005).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
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