Autonomous System Migration Mechanisms and Their Effects on the BGP AS_PATH Attribute
RFC 7705
| Document | Type |
RFC - Proposed Standard
(November 2015; No errata)
Updates RFC 4271
|
|
|---|---|---|---|
| Last updated | 2015-11-30 | ||
| Replaces | draft-ga-idr-as-migration | ||
| Stream | IETF | ||
| Formats | plain text html pdf htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Susan Hares | ||
| Shepherd write-up | Show (last changed 2015-08-06) | ||
| IESG | IESG state | RFC 7705 (Proposed Standard) | |
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Alvaro Retana | ||
| Send notices to | aretana@cisco.com | ||
| IANA | IANA review state | IANA OK - No Actions Needed | |
| IANA action state | No IANA Actions | ||
Internet Engineering Task Force (IETF) W. George
Request for Comments: 7705 Time Warner Cable
Updates: 4271 S. Amante
Category: Standards Track Apple, Inc.
ISSN: 2070-1721 November 2015
Autonomous System Migration Mechanisms
and Their Effects on the BGP AS_PATH Attribute
Abstract
This document discusses some existing commonly used BGP mechanisms
for Autonomous System Number (ASN) migration that are not formally
part of the BGP4 protocol specification. It is necessary to document
these de facto standards to ensure that they are properly supported
in future BGP protocol work.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(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.
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/rfc7705.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
George & Amante Standards Track [Page 1]
RFC 7705 AS Migration Features November 2015
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
1.2. Documentation Note . . . . . . . . . . . . . . . . . . . 3
2. ASN Migration Scenario Overview . . . . . . . . . . . . . . . 3
3. External BGP Autonomous System Migration Mechanisms . . . . . 5
3.1. Modify Inbound BGP AS_PATH Attribute . . . . . . . . . . 5
3.2. Modify Outbound BGP AS_PATH Attribute . . . . . . . . . . 7
3.3. Implementation . . . . . . . . . . . . . . . . . . . . . 8
4. Internal BGP Autonomous System Migration Mechanisms . . . . . 9
4.1. Internal BGP AS Migration . . . . . . . . . . . . . . . . 10
4.2. Implementation . . . . . . . . . . . . . . . . . . . . . 12
5. Additional Operational Considerations . . . . . . . . . . . . 13
6. Security Considerations . . . . . . . . . . . . . . . . . . . 14
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
7.1. Normative References . . . . . . . . . . . . . . . . . . 14
7.2. Informative References . . . . . . . . . . . . . . . . . 14
Appendix A. Implementation Report . . . . . . . . . . . . . . . 16
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction
This document discusses some existing commonly used BGP mechanisms
for Autonomous System Number (ASN) migration that are not formally
part of the BGP4 [RFC4271] protocol specification. These mechanisms
are local to a given BGP speaker and do not require negotiation with
or cooperation of BGP neighbors. The deployment of these mechanisms
do not need to interwork with one another to accomplish the desired
results, so slight variations between existing vendor implementations
exist and will not necessarily be harmonized due to this document.
However, it is necessary to document these de facto standards to
ensure that new implementations can be successful, and any future
protocol enhancements to BGP that propose to read, copy, manipulate,
or compare the AS_PATH attribute can do so without inhibiting the use
of these very widely used ASN migration mechanisms.
The migration mechanisms discussed here are useful to ISPs and
organizations of all sizes, but it is important to understand the
business need for these mechanisms and illustrate why they are so
critical for ISPs' operations. During a merger, acquisition, or
divestiture involving two organizations it is necessary to seamlessly
migrate both internal and external BGP speakers from one ASN to a
second ASN. The overall goal in doing so is to simplify operations
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