YANG-CBOR: Allocating SID ranges for PEN holders
draft-ietf-core-yang-sid-pen-03

CoRE Working Group                                            C. Bormann
Internet-Draft                                    Universität Bremen TZI
Intended status: Informational                           4 November 2025
Expires: 8 May 2026

            YANG-CBOR: Allocating SID ranges for PEN holders
                    draft-ietf-core-yang-sid-pen-03

Abstract

   YANG-CBOR (RFC 9254) defines YANG Schema Item iDentifiers (YANG SID),
   globally unique 63-bit unsigned integers used to identify YANG items.
   RFC 9595 defines ways to allocate these SIDs on the basis of IANA
   registries.

   The present specification employs these SID allocation mechanisms to
   allocate ranges with 100 000 63-bit SIDs each for each of the first
   1 000 000 holders of IANA-registered Private Enterprise Numbers
   (PENs), as well as ranges with 10 000 32-bit SIDs each for each of
   the first 100 000 holders.

   // The present revision –03 is intended to address the feedback from
   // the CoRE Working-Group last call.  Note that due to a regression
   // in the bib.ietf.org service (https://github.com/ietf-tools/bibxml-
   // service/issues/489 (https://github.com/ietf-tools/bibxml-service/
   // issues/489)), the reference [IANA.enterprise-numbers] may come out
   // as "*** BROKEN REFERENCE ***" in some CI systems; this will
   // certainly be fixed in the course of further processing.

About This Document

   This note is to be removed before publishing as an RFC.

   Status information for this document may be found at
   https://datatracker.ietf.org/doc/draft-ietf-core-yang-sid-pen/.

   Discussion of this document takes place on the CoRE Working Group
   mailing list (mailto:core@ietf.org), which is archived at
   https://mailarchive.ietf.org/arch/browse/core/.  Subscribe at
   https://www.ietf.org/mailman/listinfo/core/.

   Source for this draft and an issue tracker can be found at
   https://github.com/core-wg/sid-pen.

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Status of This Memo

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Example . . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Discussion  . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   7

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1.  Introduction

   YANG-CBOR [RFC9254] defines YANG Schema Item iDentifiers (YANG SID),
   globally unique 63-bit unsigned integers used to identify YANG items.
   [RFC9595] defines ways to allocate these SIDs on the basis of IANA
   registries.

   The present specification employs these SID allocation mechanisms to
   allocate ranges with 100 000 63-bit SIDs each for each of the first
   1 000 000 holders of IANA-registered Private Enterprise Numbers
   (PENs), as well as ranges with 10 000 32-bit SIDs each for each of
   the first 100 000 holders.

   IANA [is requested to allocate/has allocated] 100 000 mega-ranges,
   for the SID numbers 300 000 000 000 to 399 999 999 999.

   IANA also [is requested to allocate/has allocated] 1000 mega-ranges,
   for the SID numbers 3 000 000 000 to 3 999 999 999.

   Private Enterprise Numbers (PENs) are registered in
   [IANA.enterprise-numbers] in a low-threshold, low-overhead
   registration process.  At the time of writing (~ 37 years after
   creating this registry), around 65 000 PENs are registered.  In this
   document, the registrant for a PEN is referred to as the "PEN
   holder".

   The present specification makes the following SID ranges available to
   certain (current or future) PEN holders for allocation in a scheme
   defined by the holder:

   *  The holder of a PEN ppp ppp (< 1 000 000) can use the SID numbers
      3pp ppp p00 000 to 3pp ppp p99 999.

   *  The holder of a PEN pp ppp (< 100 000) can use the SID numbers
      3 ppp pp0 000 to 3 ppp pp9 999.

2.  Example

   The Department for Mathematics and Computer Science of Universität
   Bremen holds PEN 30810.

   To this PEN holder, the present specification confers control over
   the SID ranges:

   *  3*03 081 0*00 000 up to 3*03 081 0*99 999, and

   *  3 *308 10*0 000 up to 3 *308 10*9 999.

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   (The plaintext form of this document shows "*" characters around the
   digits conveying the PEN, which are shown in *boldface* in the
   typographic forms.)

3.  Discussion

   This allocation provides an extremely-low-threshold (zero-
   interaction) way for PEN holders to get number space for the YANG
   SIDs used in their YANG modules.  If a PEN is not already available
   to the entity needing such number space, it can be obtained in a very
   low-threshold process.  Employing this number space is, however, not
   always the approach to recommend to a module author:

   *  The larger of the two spaces uses 64-bit numbers.  The larger
      representation size of the absolute value of the SID is of
      comparatively little consequence due to the delta-encoding used
      for SIDs in YANG-CBOR.

   *  For the first 100 000 PEN holders, there also is a smaller space
      that uses 32-bit numbers.  PEN numbers that have access to this
      space are likely to run out before or around 2040; the expectation
      is that by that time there will be enough opportunities to request
      SID ranges within mega-ranges allocated by other registrants that
      this mechanism is less needed.

   *  This space has no infrastructure to discover the YANG module
      behind a SID.  Of course, each PEN holder can provide such
      infrastructure, but even then the problem remains of how to find
      that infrastructure for a SID.  (Search engines may mitigate this
      somewhat.)  On the other hand, in some cases this relative
      obscurity may be exactly what a PEN holder wants to achieve by
      using this mechanism.

      If obscurity is not the intention, one or both of the following
      approaches are encouraged:

      -  The PEN holder can provide a public repository where their YANG
         models can be found alongside the applicable SID files.  Such a
         repository may be easy to set up using a popular git forge such
         as, at the time of writing, GitHub.

      -  Implementations that employ PEN-based SIDs can facilitate
         information discovery by providing [I-D.ietf-core-yang-library]
         or another form of YANG library [RFC8525].

   Relying on the PEN registry might theoretically trigger a land-grab
   by prospective writers of YANG modules.  However, PENs have been
   around for decades (see Section 3.1.4 of [RFC1065], which continues

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   to be in force with no technical changes as Section 3.1.4 of RFC 1155
   [STD16]), and such a land-grab has not occurred for the other
   allocations implicitly provided by obtaining a PEN.

4.  IANA Considerations

   // RFC Ed.: throughout this section, please replace RFC-XXXX with the
   // RFC number of this specification and remove this note.

   This document allocates 100 000 63-bit and 1000 32-bit SID mega-
   ranges as per Section 6.3 of [RFC9595], as summarized in Table 1.

   +================+===============+==========+====+==================+
   |Entry Point     |Size           |Allocation|Org | URL              |
   |                |               |          |Name|                  |
   +================+===============+==========+====+==================+
   |3 000 000 000   |1 000 000 000  |Private   |IANA| https://rfc-     |
   |up to           |               |          |    | editor.org/info/ |
   |3 999 999 999   |               |          |    | rfcxxxx          |
   +----------------+---------------+----------+----+------------------+
   |300 000 000 000 |100 000 000 000|Private   |IANA| https://rfc-     |
   |up to           |               |          |    | editor.org/info/ |
   |399 999 999 999 |               |          |    | rfcxxxx          |
   +----------------+---------------+----------+----+------------------+

           Table 1: Megarange Allocations for use by PEN holders

   An additional contact for the allocation is: IETF CORE Working Group
   (core@ietf.org) or IETF Applications and Real-Time Area
   (art@ietf.org).

   The allocation policy inside the mega-range is "private".  The URL is
   that of the present specification.

   The management of the SID blocks of 100 000 SIDs each, 10 such blocks
   for each mega-range 3nn nnn 000 000, is delegated to the PEN holder
   for nnn nnx, where x is the sequence number of the SID block in the
   mega-range (i.e., the PEN holder for nnn nnx controls SID
   3nn nnn x00 000 to 3nn nnn x99 999).

   Similarly, the management of the SID blocks of 10 000 SIDs each, 100
   such blocks for each mega-range 3 nnn 000 000, is delegated to the
   PEN holder for nn nxx, where x is the sequence number of the SID
   block in the mega-range (i.e., the PEN holder for nn nxx controls SID
   3 nnn xx0 000 to 3 nnn xx9 999).

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   Section 6.3.2 of [RFC9595] requires an organization that requests an
   entry in the "YANG-SID Mega-Ranges" registry to ensure the technical
   capacity to manage the SID ranges within those mega-ranges for a
   period of at least 10 years (Private ranges).  The individual SID
   ranges within the mega-ranges allocated in this document are assigned
   through the registration of PEN numbers.  The technical capacity to
   ensure the sustained operation of the PEN number registry is derived
   from the demonstrated capacity of IANA to maintain this registry as
   well as the importance of a functioning PEN number registry in other
   contexts.

5.  Security Considerations

   Section 5 (Security Considerations) of [RFC9595] applies, as well as
   Section 8 (Security Considerations) of [RFC9254].  In particular, the
   fact that a certain Private Enterprise Number appears in a SID is not
   an indicator of provenance, i.e., it does not guarantee that the SID
   or underlying YANG model actually does originate from the holder of
   that PEN.  The requirement to ascertain the authoritative source of
   this information, as discussed in the above security considerations,
   remains.

6.  References

6.1.  Normative References

   [IANA.enterprise-numbers]
              "*** BROKEN REFERENCE ***".

   [RFC9254]  Veillette, M., Ed., Petrov, I., Ed., Pelov, A., Bormann,
              C., and M. Richardson, "Encoding of Data Modeled with YANG
              in the Concise Binary Object Representation (CBOR)",
              RFC 9254, DOI 10.17487/RFC9254, July 2022,
              <https://www.rfc-editor.org/rfc/rfc9254>.

   [RFC9595]  Veillette, M., Ed., Pelov, A., Ed., Petrov, I., Ed.,
              Bormann, C., and M. Richardson, "YANG Schema Item
              iDentifier (YANG SID)", RFC 9595, DOI 10.17487/RFC9595,
              July 2024, <https://www.rfc-editor.org/rfc/rfc9595>.

6.2.  Informative References

   [I-D.ietf-core-yang-library]
              Veillette, M. and I. Petrov, "Constrained YANG Module
              Library", Work in Progress, Internet-Draft, draft-ietf-
              core-yang-library-03, 11 January 2021,
              <https://datatracker.ietf.org/doc/html/draft-ietf-core-
              yang-library-03>.

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   [RFC1065]  McCloghrie, K. and M. Rose, "Structure and identification
              of management information for TCP/IP-based internets",
              RFC 1065, DOI 10.17487/RFC1065, August 1988,
              <https://www.rfc-editor.org/rfc/rfc1065>.

   [RFC8525]  Bierman, A., Bjorklund, M., Schoenwaelder, J., Watsen, K.,
              and R. Wilton, "YANG Library", RFC 8525,
              DOI 10.17487/RFC8525, March 2019,
              <https://www.rfc-editor.org/rfc/rfc8525>.

   [STD16]    Internet Standard 16,
              <https://www.rfc-editor.org/info/std16>.
              At the time of writing, this STD comprises the following:

              Rose, M. and K. McCloghrie, "Structure and identification
              of management information for TCP/IP-based internets",
              STD 16, RFC 1155, DOI 10.17487/RFC1155, May 1990,
              <https://www.rfc-editor.org/info/rfc1155>.

              Rose, M. and K. McCloghrie, "Concise MIB definitions",
              STD 16, RFC 1212, DOI 10.17487/RFC1212, March 1991,
              <https://www.rfc-editor.org/info/rfc1212>.

Acknowledgments

   This document was inspired by the discussion of the authors of
   [RFC9254] and [RFC9595] on how to handle Rob Wilton's feedback.

Author's Address

   Carsten Bormann
   Universität Bremen TZI
   Postfach 330440
   D-28359 Bremen
   Germany
   Phone: +49-421-218-63921
   Email: cabo@tzi.org

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