IDR J. Snijders
Internet-Draft NTT
Intended status: Standards Track December 29, 2016
Expires: July 2, 2017

Deprecation of BGP Path Attribute values 30, 31, 129, 241, 242, and 243


This document requests IANA to mark BGP path attribute values 30, 31, 129, 241, 242, and 243 as "deprecated".

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at

Internet-Drafts are draft documents valid for a maximum of six months 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."

This Internet-Draft will expire on July 2, 2017.

Copyright Notice

Copyright (c) 2016 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 ( 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.

Table of Contents

1. Introduction

It has been discovered that certain BGP Path Attribute values have been used in BGP implementations which have been deployed in the wild while not being assigned by the IANA for such usage. Unregistered usage of BGP Path Attribute values can lead to deployment problems for new technologies.

The use of these unregistered values was noticed when BGP Large Communities attribute [I-D.ietf-idr-large-community] was initially assigned value 30 by IANA. It was subsequently discovered that a widely-deployed BGP-4 [RFC4271] implementation had released code which used path attribute 30 and which applied a "Treat-as-withdraw" [RFC7606] strategy to routes containing a valid Large Community attribute, since it was expecting a different data structure. Because these routes were dropped, early adopters of Large Communities were unreachable from parts of the Internet. As a workaround, a new Early IANA Allocation was requested.

The squatting of values 30, 31, 129, 241, 242 and 243 has been confirmed by the involved vendors or through source code review.

2. IANA Considerations

Per this document, IANA is requested to mark values 30, 31, 129, 241, 242, and 243 as "deprecated" in the "BGP Path Attributes" registry under the "Border Gateway Protocol (BGP) Parameters" group. The marking "deprecated" meaning "use is not recommended" ([I-D.leiba-cotton-iana-5226bis]).

3. Security Considerations

There are no meaningful security consequences arising from this registry update.

4. Informative References

[I-D.ietf-idr-large-community] Heitz, J., Snijders, J., Patel, K., Bagdonas, I. and N. Hilliard, "BGP Large Communities", Internet-Draft draft-ietf-idr-large-community-11, December 2016.
[I-D.leiba-cotton-iana-5226bis] Cotton, M., Leiba, B. and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", Internet-Draft draft-leiba-cotton-iana-5226bis-18, September 2016.
[RFC4271] Rekhter, Y., Li, T. and S. Hares, "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, DOI 10.17487/RFC4271, January 2006.
[RFC7606] Chen, E., Scudder, J., Mohapatra, P. and K. Patel, "Revised Error Handling for BGP UPDATE Messages", RFC 7606, DOI 10.17487/RFC7606, August 2015.

Appendix A. Acknowledgements

The author would like to gratefully acknowledge Marlien Vijfhuizen who helped discover the squatting of value 30, and Nick Hilliard for editorial feedback.

Author's Address

Job Snijders NTT Communications Theodorus Majofskistraat 100 Amsterdam, 1065 SZ NL EMail: