RFC 9890 PROPOSED STANDARD YANG · IANA · REGISTRIES
An Update to YANG Module Names Registration
Only the first version of a YANG module 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
ISO Plain Language
On this page
PROBLEMRFC 6020 told IANA that every YANG module and submodule name in its registry must be unique, but in practice a module and all of its revisions share one name, so the written rule did not match what IANA did.
MECHANISMThis RFC replaces that text so that only the name and XML namespace of an initial version must be unique, while every revision must keep the name and namespace of the initial version.
WHY IT MATTERSThe written rule now matches IANA's practice, and this document is listed as an additional reference for the YANG Module Names registry.
§1A Rule That Did Not Match Practice
RFC 6020 created a registry called "YANG Module Names" for the names of YANG modules and submodules. Section 14 of that RFC says every module and submodule name in the registry MUST be unique.
This document reports that the way IANA runs the registry does not follow that guidance, and amends Section 14 so the rule describes what IANA actually does with a module and its revisions.
The old rule said every name must be different from every other name. In practice, a new version of a module reuses the old name, so the rule needed correcting.
§3.2The Replacement Rule
The document prints the old text and the new text side by side. The old text required uniqueness for all module and submodule names and all XML namespaces. The new text separates an initial version from its revisions.
- Modules and their revisions are both kept in the registry.
- All initial version module and submodule names MUST be unique.
- All XML namespaces of initial version modules MUST be unique.
- Every module and submodule revision MUST have the same name as the initial version.
- Every module revision MUST have the same XML namespace as the initial version.
Only the first version of a module needs a brand-new name and its own namespace. Every later revision must repeat both of them exactly.
| Rule | What it covers |
|---|---|
| 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 modules and submodules |
| New: namespaces MUST be unique THIS RFC | Initial version modules |
| New: revisions MUST reuse name and namespace THIS RFC | Every module and submodule revision |
§3.1Registry and Operational Notes
IANA has updated the "YANG Module Names" registry, which sits under the "YANG Parameters" registry group, to list this document as an additional reference. The RFC says this is needed because its procedure is now the authority for assigning names there.
The document states that it introduces no new operations or manageability requirements and no new or increased security risks. Its text was originally part of a YANG author guidelines document.
The registry now points to this document as the rule to follow. Nothing else about running a network changes.
§4References
[RFC6020]RFC 6020Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, October 2010.October 2010[RFC2119]RFC 2119Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.March 1997[RFC8174]RFC 8174Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, May 2017.May 2017
[IANA-MOD-NAMES]IANA, "YANG Module Names".