RFC 9890 PROPOSED STANDARD YANG · IANA · REGISTRIES
An Update to YANG Module Names Registration
Only a YANG module's first version needs a unique name; later revisions keep that name and namespace.
RFC EDITOR
Bierman, A., Boucadair, M., Ed., and Q. Wu, "An Update to YANG Module Names Registration", RFC 9890, DOI 10.17487/RFC9890, October 2025, <https://www.rfc-editor.org/info/rfc9890>.
BIBTEX
@misc{rfc9890,
series = {Request for Comments},
number = 9890,
howpublished = {RFC 9890},
publisher = {RFC Editor},
doi = {10.17487/RFC9890},
url = {https://www.rfc-editor.org/info/rfc9890},
author = {A. Bierman and M. Boucadair and Q. Wu},
title = {{An Update to YANG Module Names Registration}},
pagetotal = 5,
year = 2025,
month = oct,
} LINEAGE · FROM THE RFC INDEXOpen full graph →
RFC text
Contents
Internet Engineering Task Force (IETF) A. Bierman
Request for Comments: 9890 YumaWorks
Updates: 6020 M. Boucadair, Ed.
Category: Standards Track Orange
ISSN: 2070-1721 Q. Wu
Huawei
October 2025
An Update to YANG Module Names Registration
Abstract
This document amends the IANA guidance on the uniqueness of YANG
module and submodule names.
The document updates RFC 6020 to clarify how modules and their
revisions are handled by IANA.
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
https://www.rfc-editor.org/info/rfc9890.
Copyright Notice
Copyright (c) 2025 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Revised BSD License text as described in Section 4.e of the
Trust Legal Provisions and are provided without warranty as described
in the Revised BSD License.
Table of Contents
1. Introduction
2. Requirements Notation
3. IANA Considerations
3.1. Update YANG Parameters Registry
3.2. Revisions of Published Modules
4. Operational Considerations
5. Security Considerations
6. References
6.1. Normative References
6.2. Informative References
Acknowledgments
Authors' Addresses
1. Introduction
[RFC6020] defines a registry for YANG module and submodule names,
called "YANG Module Names" [IANA-MOD-NAMES].
Specifically, IANA considerations to register YANG module and
submodule names are specified in Section 14 of [RFC6020]. These
considerations require that all module and submodule names in the
registry must be unique. However, the practice followed by IANA is
not consistent with that guidance.
This document amends the guidance on the uniqueness of names
(Section 14 of [RFC6020]) to comply with the IANA practices for
registering modules and their revisions.
2. Requirements Notation
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.
3. IANA Considerations
3.1. Update YANG Parameters Registry
IANA has updated the "YANG Module Names" registry under the "YANG
Parameters" registry group [IANA-MOD-NAMES] to list this document as
an additional reference. This update is needed because the procedure
in this document is authoritative for assigning names in that
registry.
3.2. Revisions of Published Modules
This document amends the guidance on the uniqueness of names,
initially defined in Section 14 of [RFC6020], as follows:
OLD:
| All module and submodule names in the registry MUST be unique.
|
| All XML namespaces in the registry MUST be unique.
NEW:
| Modules and their revisions are maintained in the registry.
|
| All initial version module and submodule names in the registry
| MUST be unique.
|
| All XML namespaces of initial version modules in the registry MUST
| be unique.
|
| All module and submodule revisions MUST have the same name as the
| one in the initial version of the module and submodule.
|
| All module revisions MUST have the same XML namespace as the
| initial version of the module.
4. Operational Considerations
This document aligns an IANA policy with the practice for handling
YANG module names (Section 3.2). As such, there are no new
operations or manageability requirements introduced by this document.
5. Security Considerations
This document defines a new IANA action (Section 3.1) and an update
(Section 3.2) to an IANA registration procedure defined in [RFC6020].
It does not introduce any new or increased security risks that need
to be discussed.
6. References
6.1. 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,
<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>.
[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
[IANA-MOD-NAMES]
IANA, "YANG Module Names",
<https://www.iana.org/assignments/yang-parameters/>.
[YANG-GUIDE]
Bierman, A., Boucadair, M., Ed., 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>.
Acknowledgments
The content of this document was part of [YANG-GUIDE].
Mahesh Jethanandani suggested to offload this part from [YANG-GUIDE].
Thanks to Mahesh and Kent Watsen for the discussion and comments.
Thanks to Mallory Knodel for the GENART review and Barry Leiba for
the ARTART review.
Thanks Mike Bishop for the IESG review.
Authors' Addresses
Andy Bierman
YumaWorks
United States of America
Email: andy@yumaworks.com
Mohamed Boucadair (editor)
Orange
France
Email: mohamed.boucadair@orange.com
Qin Wu
Huawei
China
Email: bill.wu@huawei.com
AI ELI5
On this page
PROBLEMRFC 6020 says all YANG module and submodule names in the IANA registry must be unique, but the practice IANA actually follows, where revisions of a module share its name, did not match that guidance.
MECHANISMThe RFC replaces the uniqueness text so that only initial-version names and XML namespaces must be unique, while every revision must keep the name and namespace of the initial version.
WHY IT MATTERSThe written rule now matches IANA practice, and this document becomes an additional reference for the YANG Module Names registry.
§1A Rule That Did Not Match Practice
RFC 6020 defines a registry for YANG module and submodule names, called "YANG Module Names". Section 14 of that RFC requires all module and submodule names in the registry to be unique. The RFC points out that the practice followed by IANA is not consistent with that guidance.
RFC 9890 amends the guidance so that it complies with how IANA registers modules and their revisions.
The rule said every name must be different, but in real life new versions of the same thing kept the same name. So the rule needed fixing to match.
§3.2The Replacement Text
The old text said all module and submodule names in the registry MUST be unique and all XML namespaces MUST be unique. The new text says modules and their revisions are maintained in the registry, and then separates initial versions from revisions.
- All initial version module and submodule names MUST be unique.
- All XML namespaces of initial version modules MUST be unique.
- All module and submodule revisions MUST have the same name as the initial version.
- All module revisions MUST have the same XML namespace as the initial version.
The first copy of a book needs its own special title. New editions of the book keep that same title.
| Rule | Applies to |
|---|---|
| Old: names MUST be unique | All module and submodule names |
| Old: XML namespaces MUST be unique | All XML namespaces |
| New: names MUST be unique THIS RFC | Initial version names only |
| New: namespaces MUST be unique THIS RFC | Initial version modules only |
| New: revisions MUST keep the name and namespace THIS RFC | Every revision |
§3.1IANA and Other Considerations
IANA has updated the "YANG Module Names" registry, under the "YANG Parameters" registry group, to list this document as an additional reference. The RFC says this is needed because its procedure is authoritative for assigning names in that registry.
The document aligns an IANA policy with existing practice, so it adds no new operations or manageability requirements and no new or increased security risks. The text of the document was previously part of a YANG guidelines draft.
The official list now points to this new rule as the authority. Nothing else changes for anyone.
§4References
[RFC6020]RFC 6020Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, October 2010.October 2010
[IANA-MOD-NAMES]IANA, "YANG Module Names".