YANG module file name convention
draft-ietf-netmod-yang-module-filename-03

NETMOD Working Group                                        P. Andersson
Internet-Draft                                             Ionio Systems
Updates: 6020, 7950, I-D.ietf-netmod-rfc8407bis          20 October 2025
         (if approved)                                                  
Intended status: Standards Track                                        
Expires: 23 April 2026

                    YANG module file name convention
               draft-ietf-netmod-yang-module-filename-03

Abstract

   This document presents YANG module file name convention.  The
   convention extends the current YANG module file name using
   revision-date, with the YANG semantic version extension.  The YANG
   semantic version extension allows for an informative version to be
   associated with a particular YANG module revision.

   This documents updates RFCs 6020, 7950, and draft-ietf-netmod-
   rfc8407bis.

Status of This Memo

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   This Internet-Draft will expire on 23 April 2026.

Copyright Notice

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   Please review these documents carefully, as they describe your rights

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   and restrictions with respect to this document.  Code Components
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   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   2
     1.2.  Motivation  . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Module file names . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Coexistence with YANG Semver  . . . . . . . . . . . . . .   3
     2.2.  Known incompatibilities . . . . . . . . . . . . . . . . .   4
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     5.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   This document defines the YANG module file convention.  It extends
   the current convention defined in [RFC6020], [RFC7950], and
   [I-D.ietf-netmod-rfc8407bis], which uses revision-date, with the YANG
   semantic version extension defined in [I-D.ietf-netmod-yang-semver].

1.1.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "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.

1.2.  Motivation

   The motivation for using YANG semantic version instead of revision
   date is that it conveys additional information to the user.  A
   revision date only tells the user that it has been updated, while,
   for instance, a YANG Semver version can tell the user about the
   module's compatibility level at a glance.  Having this information
   available as early as possible, i.e. in the module file name, makes
   it possible to quickly identify the module revision; compared to
   searching in the file contents and checking the revisions.  Having
   the YANG semantic version visible in the file name will make it
   easier to handle large sets of YANG modules.

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2.  Module file names

   This section updates Section 5.2 of [RFC7950], Section 5.2 of
   [RFC6020], and Section 3.2 of [I-D.ietf-netmod-rfc8407bis].

   If a revision has an associated YANG semantic version (ysv:version)
   then it MAY use the YANG semantic version instead of the revision
   date in the file name of a YANG file, where it takes the form:

       module-or-submodule-name [['@' revision-date]['#' ysv:version]]
           ( '.yang' / '.yin' )

   E.g., acme-router-module@2024-05-15.yang or
   acme-router-module#2.0.3.yang.

   In short, the YANG semantic version file name scheme is recommended
   in order to simplify for module consumers, i.e. to convey
   compatibility status at a glance without needing to read the module.

   YANG module (or submodule) files MAY be identified using either
   revision-date or YANG semantic version (ysv:version).  Typically,
   only one file name SHOULD exist for the same module (or submodule)
   revision.  Two file names, one with the revision date and another
   with the YANG semantic version, MAY exist for the same module (or
   submodule) revision, e.g., when migrating from one scheme to the
   other.

2.1.  Coexistence with YANG Semver

   As can be seen above, all valid identifiers for YANG semantic version
   are valid in the filename as well.  Section 4.3 of
   [I-D.ietf-netmod-yang-semver]

   The following example is a valid YANG module file name

       example-module#2.3.1_non_compatible+build2237refM443ss.yang

   One consequence of this is that there might exist two child modules
   of version 2.0.0 with the same X.Y.Z digits (2.0.1) but different
   version labels:

       2.0.1-draft-superman-super-stuff-03

       2.0.1-draft-batman-cool-addition-07   (a competing draft)

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2.2.  Known incompatibilities

   There are currently no known publicly available tools that support
   the YANG semantic version file name schema.  There are known
   proprietary tooling that already uses the file name schema presented
   in this document.

   At the IETF 119 Hackathon, there was a project that investigated the
   feasibility to modify popular YANG tooling to support the proposed
   schema.  There was a successful attempt to modify pyang to support
   the file name schema and also "recommended-min" previously included
   in [I-D.ietf-netmod-yang-module-versioning].  Furthermore, there were
   efforts in researching yanger and libyang to support the schema, but
   the hackathon ended before these projects could be concluded.

3.  IANA Considerations

   The "YANG Module Names" Registry will need to support YANG modules
   with both the existing file name convention and the file name
   convention defined in this document.

   The registry SHOULD avoid publishing multiple instances of the same
   YANG module with different file names.  If this situation is
   motivated, for instance due to maintaining backwards compatibility,
   it can however be possible that the registry needs to publish the
   same YANG module with multiple file names.  For instance, if a YANG
   module starts to use YANG Semver, it might simplify for consumers to
   publish this with filename and revision-date and also filename and
   ysv:version.

4.  Security Considerations

   There are no security considerations for this draft.

5.  References

5.1.  Normative References

   [I-D.ietf-netmod-rfc8407bis]
              Bierman, A., Boucadair, M., and Q. Wu, "Guidelines for
              Authors and Reviewers of Documents Containing YANG Data
              Models", Work in Progress, Internet-Draft, draft-ietf-
              netmod-rfc8407bis-28, 5 June 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
              rfc8407bis-28>.

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   [I-D.ietf-netmod-yang-module-versioning]
              Wilton, R., Rahman, R., Lengyel, B., Clarke, J., and J.
              Sterne, "Updated YANG Module Revision Handling", Work in
              Progress, Internet-Draft, draft-ietf-netmod-yang-module-
              versioning-14, 6 October 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
              yang-module-versioning-14>.

   [I-D.ietf-netmod-yang-semver]
              Clarke, J., Wilton, R., Rahman, R., Lengyel, B., Sterne,
              J., and B. Claise, "YANG Semantic Versioning", Work in
              Progress, Internet-Draft, draft-ietf-netmod-yang-semver-
              24, 29 September 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
              yang-semver-24>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <https://www.rfc-editor.org/info/rfc6020>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

5.2.  Informative References

Acknowledgements

   The author would like to thank Joe Clarke, Reshad Rahman, for their
   excellent technical reviews, support, and guidance.

Author's Address

   Per Andersson
   Ionio Systems
   Email: per.ietf@ionio.se

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