YANG module file name convention
draft-ietf-netmod-yang-module-filename-07

NETMOD Working Group                                        P. Andersson
Internet-Draft                                             Ionio Systems
Updates: 6020, 7950, I-D.ietf-netmod-rfc8407bis             2 April 2026
         (if approved)                                                  
Intended status: Standards Track                                        
Expires: 4 October 2026

                    YANG module file name convention
               draft-ietf-netmod-yang-module-filename-07

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 4 October 2026.

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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.  YANG Module File Names  . . . . . . . . . . . . . . . . . . .   3
     2.1.  Coexistence with YANG Semver  . . . . . . . . . . . . . .   3
     2.2.  Known Incompatibilities . . . . . . . . . . . . . . . . .   4
   3.  Operational Considerations  . . . . . . . . . . . . . . . . .   4
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   6
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   This document defines the YANG module file name 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

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   easier to handle large sets of YANG modules.

2.  YANG 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 a YANG file MUST be created that use the YANG semantic version
   in the file name.  Additionally, a YANG file with the revision-date
   MAY be created.  The name of the files SHOULD be of the form:

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

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

   In short, the YANG semantic version file name scheme is recommended,
   as its use will convey compatibility status at a glance withouth the
   need to read the module.

   If the YANG module (or submodule) has an associated YANG semantic
   version (ysv:version), then a file name that use the YANG semantic
   version MUST be created.  In addition, a file with the revision date
   in the file name MAY be created as well.

2.1.  Coexistence with YANG Semver

   As can be seen above, all valid identifiers for YANG semantic version
   are valid in the file name 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.  Operational Considerations

   The delimiter symbol for YANG Semver is "#", the number sign.  Since
   this symbol may have special, reserved, or semantic meaning in some
   contexts, it is important to escape or encode it according to the
   context.

   In URI and URL contexts, the delimiter symbol needs to be percent
   encoded where it would be interpreted semantically (e.g. as the
   fragment identifier) by the software reading it.  The percent
   encoding for "#" is "%23".

   In online registries, such as IANA registries and code repositories,
   it is expected that the full YANG module file name is retained.  This
   means that a server publishing a YANG module with a YANG Semver
   delimited by "#" needs to ensure that the client doesn't misinterpret
   the delimiter as e.g. a URL fragment identifier in links.  A client
   needs to percent encode direct requests for YANG modules where the
   file name includes a YANG Semver delimiter symbol.

4.  IANA Considerations

   For complete guidance on how to handle YANG modules in RFCs and IANA
   registries, with regards to [I-D.ietf-netmod-yang-module-versioning],
   [I-D.ietf-netmod-yang-semver], and YANG module file names, see
   [I-D.ietf-netmod-iana-yang-guidance].

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

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   The registry MUST create a file with a YANG semantic version if the
   YANG module (or submodule) has an associated YANG semantic version
   (ysv:version).  The registry MUST also create a file with the YANG
   module using a file name with the revision date.  It MUST be ensured
   that the files' contents are identical.

5.  Security Considerations

   There are no security considerations for this draft.

6.  References

6.1.  Normative References

   [I-D.ietf-netmod-iana-yang-guidance]
              Wilton, R., "Guidance for Managing YANG Modules in RFCs
              and IANA Registries", Work in Progress, Internet-Draft,
              draft-ietf-netmod-iana-yang-guidance-01, 17 March 2026,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
              iana-yang-guidance-01>.

   [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>.

   [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-15, 18 October 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
              yang-module-versioning-15>.

   [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>.

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   [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>.

6.2.  Informative References

Acknowledgements

   The author would like to thank Joe Clarke, Reshad Rahman, Mahesh
   Jethanandani, David Dong, Aihua Guo, Barry Leiba, Joel M.  Halpern,
   and Meir Goldman for their excellent technical reviews, support, and
   guidance.

Author's Address

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

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