Internet Engineering Task Force (IETF)                       J. Snijders
Request for Comments: 8093                                           NTT
Category: Standards Track                                  February 2017
ISSN: 2070-1721


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

Abstract

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

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 7841.

   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/rfc8093.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   2
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .   2
   4.  Informative References  . . . . . . . . . . . . . . . . . . .   3
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   3
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   3

1.  Introduction

   It has been discovered that certain BGP Path Attribute values have
   been used in BGP implementations that have been deployed in the wild
   while not being assigned by 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 the BGP Large
   Communities attribute [RFC8092] was initially assigned value 30 by
   IANA.  It was subsequently discovered that a widely deployed BGP-4
   [RFC4271] implementation had released code that used path attribute
   30 and that 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

   IANA has marked values 30, 31, 129, 241, 242, and 243 as "Deprecated"
   in the "BGP Path Attributes" subregistry under the "Border Gateway
   Protocol (BGP) Parameters" registry.  The marking "Deprecated" means
   "use is not recommended" ([IANA-GUIDELINES]).

3.  Security Considerations

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

4.  Informative References

   [IANA-GUIDELINES]
              Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", Work in
              Progress, draft-leiba-cotton-iana-5226bis-18, September
              2016.

   [RFC4271]  Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
              Border Gateway Protocol 4 (BGP-4)", RFC 4271,
              DOI 10.17487/RFC4271, January 2006,
              <http://www.rfc-editor.org/info/rfc4271>.

   [RFC7606]  Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K.
              Patel, "Revised Error Handling for BGP UPDATE Messages",
              RFC 7606, DOI 10.17487/RFC7606, August 2015,
              <http://www.rfc-editor.org/info/rfc7606>.

   [RFC8092]  Heitz, J., Ed., Snijders, J., Ed., Patel, K., Bagdonas,
              I., and N. Hilliard, "BGP Large Communities Attribute",
              RFC 8092, DOI 10.17487/RFC8092, February 2017,
              <http://www.rfc-editor.org/info/rfc8092>.

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
   The Netherlands

   Email: job@ntt.net