Internet Engineering Task Force (IETF)                         A. Farrel
Request for Comments: 9029                            Old Dog Consulting
Updates: 7752                                                  June 2021
Category: Standards Track
ISSN: 2070-1721

Updates to the Allocation Policy for the Border Gateway Protocol - Link
                  State (BGP-LS) Parameters Registries


   RFC 7752 defines the Border Gateway Protocol - Link State (BGP-LS).
   IANA created a registry consistent with that document called "Border
   Gateway Protocol - Link State (BGP-LS) Parameters" with a number of
   subregistries.  The allocation policy applied by IANA for those
   registries is "Specification Required", as defined in RFC 8126.

   This document updates RFC 7752 by changing the allocation policy for
   all of the registries to "Expert Review" and by updating the guidance
   to the designated experts.

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

Copyright Notice

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Table of Contents

   1.  Introduction
     1.1.  Requirements Language
   2.  IANA Considerations
     2.1.  Guidance for Designated Experts
   3.  Security Considerations
   4.  Normative References
   Author's Address

1.  Introduction

   "North-Bound Distribution of Link-State and Traffic Engineering (TE)
   Information Using BGP" [RFC7752] requested IANA to create a registry
   called "Border Gateway Protocol - Link State (BGP-LS) Parameters"
   with a number of subregistries.  The allocation policy applied by
   IANA for those registries is "Specification Required", as defined in

   The "Specification Required" policy requires evaluation of any
   assignment request by a "designated expert", and guidelines for any
   such experts are given in Section 5.1 of [RFC7752].  In addition,
   this policy requires that "the values and their meanings must be
   documented in a permanent and readily available public specification,
   in sufficient detail so that interoperability between independent
   implementations is possible" [RFC8126].  Further, the intention
   behind "permanent and readily available" is that "a document can
   reasonably be expected to be findable and retrievable long after IANA
   assignment of the requested value" [RFC8126].

   Another allocation policy called "Expert Review" is defined in
   [RFC8126].  This policy also requires Expert Review but has no
   requirement for a formal document.

   All reviews by designated experts are guided by advice given in the
   document that defined the registry and set the allocation policy.

   This document updates [RFC7752] by changing the allocation policy for
   all of the registries to "Expert Review" and updating the guidance to
   the designated experts.

1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

2.  IANA Considerations

   IANA maintains a registry called "Border Gateway Protocol - Link
   State (BGP-LS) Parameters".  This registry contains four

   *  BGP-LS NLRI-Types

   *  BGP-LS Protocol-IDs

   *  BGP-LS Well-Known Instance-IDs

   *  BGP-LS Node Descriptor, Link Descriptor, Prefix Descriptor, and
      Attribute TLVs

   IANA has changed the assignment policy for each of these registries
   to "Expert Review".

   IANA has also added this document as a reference for the registries
   mentioned above.

2.1.  Guidance for Designated Experts

   Section 5.1 of [RFC7752] gives guidance to designated experts.  This
   section replaces that guidance.

   In all cases of review by the designated expert described here, the
   designated expert is expected to check the clarity of purpose and use
   of the requested code points.  The following points apply to the
   registries discussed in this document:

   1.  Application for a code point allocation may be made to the
       designated experts at any time and MUST be accompanied by
       technical documentation explaining the use of the code point.
       Such documentation SHOULD be presented in the form of an
       Internet-Draft but MAY arrive in any form that can be reviewed
       and exchanged amongst reviewers.

   2.  The designated experts SHOULD only consider requests that arise
       from Internet-Drafts that have already been accepted as working
       group documents or that are planned for progression as AD-
       Sponsored documents in the absence of a suitably chartered
       working group.

   3.  In the case of working group documents, the designated experts
       MUST check with the working group chairs that there is consensus
       within the working group to make the allocation at this time.  In
       the case of AD-Sponsored documents, the designated experts MUST
       check with the AD for approval to make the allocation at this

   4.  If the document is not adopted by the IDR Working Group (or its
       successor), the designated expert MUST notify the IDR mailing
       list (or its successor) of the request and MUST provide access to
       the document.  The designated expert MUST allow two weeks for any
       response.  Any comments received MUST be considered by the
       designated expert as part of the subsequent step.

   5.  The designated experts MUST then review the assignment requests
       on their technical merit.  The designated experts MAY raise
       issues related to the allocation request with the authors and on
       the IDR (or successor) mailing list for further consideration
       before the assignments are made.

   6.  The designated expert MUST ensure that any request for a code
       point does not conflict with work that is active or already
       published within the IETF.

   7.  Once the designated experts have granted approval, IANA will
       update the registry by marking the allocated code points with a
       reference to the associated document.

   8.  In the event that the document is a working group document or is
       AD Sponsored, and that document fails to progress to publication
       as an RFC, the working group chairs or AD SHOULD contact IANA to
       coordinate about marking the code points as deprecated.  A
       deprecated code point is not marked as allocated for use and is
       not available for allocation in a future document.  The WG chairs
       may inform IANA that a deprecated code point can be completely
       deallocated (i.e., made available for new allocations) at any
       time after it has been deprecated if there is a shortage of
       unallocated code points in the registry.

3.  Security Considerations

   The security considerations described in Section 8 of [RFC7752] still

   Note that the change to the Expert Review guidelines makes the
   registry and the designated experts slightly more vulnerable to
   denial-of-service attacks through excessive and bogus requests for
   code points.  It is expected that the registry cannot be effectively
   attacked because the designated experts would, themselves, fall to
   any such attack first.  Designated experts are expected to report to
   the IDR Working Group chairs and responsible Area Director if they
   believe an attack to be in progress and should immediately halt all
   requests for allocation.  This may temporarily block all legitimate
   requests until mitigations have been put in place.

4.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,

   [RFC7752]  Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
              S. Ray, "North-Bound Distribution of Link-State and
              Traffic Engineering (TE) Information Using BGP", RFC 7752,
              DOI 10.17487/RFC7752, March 2016,

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <>.


   This work is based on the IANA Considerations described in Section 5
   of [RFC7752].  The author thanks the people who worked on that

   The author would like to thank John Scudder for suggesting the need
   for this document.

   Thanks to John Scudder, Donald Eastlake 3rd, Ketan Talaulikar, and
   Alvaro Retana for their review, comments, and discussion.

   Additional thanks to Gyan Mishra, Acee Lindem, Ketan Talaulikar, Les
   Ginsberg, Bruno Decraene, Benjamin Kaduk, and Martin Vigoureux for
   engaging in discussion on the details of this work.

Author's Address

   Adrian Farrel
   Old Dog Consulting