Recommendations for Creating IANA-Maintained YANG Modules
draft-boucadair-netmod-iana-registries-02
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| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Author | Mohamed Boucadair | ||
| Last updated | 2022-03-25 | ||
| Stream | (None) | ||
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| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
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draft-boucadair-netmod-iana-registries-02
netmod M. Boucadair
Internet-Draft Orange
Updates: 8407 (if approved) 25 March 2022
Intended status: Standards Track
Expires: 26 September 2022
Recommendations for Creating IANA-Maintained YANG Modules
draft-boucadair-netmod-iana-registries-02
Abstract
This document provides a set of guidelines for YANG module authors
related to the design of IANA-maintained modules. These guidelines
are meant to leverage existing IANA registries and use YANG as just
another format to present the content of these registries.
This document updates RFC 8407 by providing additional guidelines for
IANA-maintained modules. It does not change anything written in RFC
8407.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 26 September 2022.
Copyright Notice
Copyright (c) 2022 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/
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Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
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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
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Guidelines for IANA-Maintained Registries . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
7.1. Normative References . . . . . . . . . . . . . . . . . . 4
7.2. Informative References . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
IANA maintains a set of registries that are key for interoperability.
The content of these registries are usually available using various
formats (e.g., plain text, XML). However, there were some confusion
in the past about whether the content of some registries is dependent
on a specific representation format. For example, Section 5 of
[RFC8892] was published to clarify that MIB and YANG modules are
merely additional formats in which the "Interface Types (ifType)" and
"Tunnel Types (tunnelType)" registries are available. The MIB
[RFC2863] and YANG modules [RFC7224][RFC8675] are not separate
registries, and the same values are always present in all formats of
the same registry.
Also, some YANG modules include parameters and values directly in a
module that is not maintained by IANA while these are populated in an
IANA registry. Such a design is suboptimal as it creates another
source of information that may deviate from the IANA registry as new
values are assigned.
For the sake of consistency, better flexibility to support new
values, and maintaining IANA registries as the unique authoritative
source of information, when such an information is maintained in a
registry, this document encourages the use of IANA-maintained
modules.
Section 3 updates the guidelines in [RFC8407].
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2. 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.
This document makes use of the terms defined in Section 2 of
[RFC8407].
3. Guidelines for IANA-Maintained Registries
When designing a YANG module for a functionality governed by a
protocol for which IANA maintains a registry, it is RECOMMENDED to
specify an IANA-maintained module that echoes the content of that
registry. This is superior to including that content in an IETF-
maintained module.
When one or multiple sub-registries are available under the same
registry, it is RECOMMENDED to define an IANA-maintained module for
each sub-registry. However, module designers MAY consider defining
one single IANA-maintained module that covers all sub-registries if
maintaining that single module is manageable (e.g., very few values
are present or expected to be present for each sub-registry). An
example of such a module is documented in Section 5.2 of [RFC9132].
An IANA-maintained module MAY use identities (e.g., [RFC8675]) or
enumerations (e.g., [RFC9108]). The final decision is left to the
module designers and should be made based upon specifics related to
the intended use of the module. It is worth mentioning that
identities are useful if the registry entries are organized
hierarchically, possibly including multiple inheritances. It is
RECOMMENDED that the reasoning for the design choice is documented in
the companion specification document that registers the module. For
example, [I-D.ietf-dots-telemetry] defines an IANA-maintained module
that uses enumerations for the following reason:
"The DOTS telemetry module (Section 10.1) uses "enumerations" rather
than "identities" to define units, samples, and intervals because
otherwise the namespace identifier "ietf-dots-telemetry" must be
included when a telemetry attribute is included (e.g., in a
mitigation efficacy update). The use of "identities" is thus
suboptimal from a message compactness standpoint; one of the key
requirements for DOTS messages."
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Designers of IANA-maintained modules MAY supply the full Initial
version of the module in a specification document that registers the
module or only a script to be used (including by IANA) for generating
the module (e.g., an XSLT stylesheet as in Appendix A of [RFC9108]).
When a script is used, the Internet-Draft that defines an IANA-
maintained module SHOULD include an appendix with the initial full
version of the module. Including such an appendix in pre-RFC
versions is meant to assess the correctness of the outcome of the
supplied script. The authors MUST include a note to the RFC Editor
requesting that the appendix be removed before publication as RFC.
Initial versions of IANA-maintained modules that are published in
RFCs may be misused despite the appropriate language to refer to the
IANA registry to retrieve the up-to-date module. This is problematic
for interoperability (e.g., when values are deprecated or are
associated with a new meaning).
Note: [Style] provides XSLT 1.0 stylesheets and other tools for
translating IANA registries to YANG modules. The tools can be
used to generate up-to-date revisions of an IANA-maintained module
based upon the XML representation of an IANA registry.
4. IANA Considerations
This document does not require any IANA action.
5. Security Considerations
This document does not introduce new concerns other than those
already discussed in Section 15 of [RFC8407].
6. Acknowledgements
This document is triggered by a discussion the author had with Dhruv
Dhody and Jensen Zhang.
Thanks to Juergen Schoenwaelder and Ladislav Lhotka for the
discussion and valuable comments. Special thanks to Ladislav Lhotka
for sharing more context that led to the design documented in
[RFC9108].
7. References
7.1. 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>.
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[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>.
[RFC8407] Bierman, A., "Guidelines for Authors and Reviewers of
Documents Containing YANG Data Models", BCP 216, RFC 8407,
DOI 10.17487/RFC8407, October 2018,
<https://www.rfc-editor.org/info/rfc8407>.
7.2. Informative References
[I-D.ietf-dots-telemetry]
Boucadair, M., Reddy.K, T., Doron, E., Chen, M., and J.
Shallow, "Distributed Denial-of-Service Open Threat
Signaling (DOTS) Telemetry", Work in Progress, Internet-
Draft, draft-ietf-dots-telemetry-25, 21 March 2022,
<https://www.ietf.org/archive/id/draft-ietf-dots-
telemetry-25.txt>.
[RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group
MIB", RFC 2863, DOI 10.17487/RFC2863, June 2000,
<https://www.rfc-editor.org/info/rfc2863>.
[RFC7224] Bjorklund, M., "IANA Interface Type YANG Module",
RFC 7224, DOI 10.17487/RFC7224, May 2014,
<https://www.rfc-editor.org/info/rfc7224>.
[RFC8675] Boucadair, M., Farrer, I., and R. Asati, "A YANG Data
Model for Tunnel Interface Types", RFC 8675,
DOI 10.17487/RFC8675, November 2019,
<https://www.rfc-editor.org/info/rfc8675>.
[RFC8892] Thaler, D. and D. Romascanu, "Guidelines and Registration
Procedures for Interface Types and Tunnel Types",
RFC 8892, DOI 10.17487/RFC8892, August 2020,
<https://www.rfc-editor.org/info/rfc8892>.
[RFC9108] Lhotka, L. and P. Špaček, "YANG Types for DNS Classes and
Resource Record Types", RFC 9108, DOI 10.17487/RFC9108,
September 2021, <https://www.rfc-editor.org/info/rfc9108>.
[RFC9132] Boucadair, M., Ed., Shallow, J., and T. Reddy.K,
"Distributed Denial-of-Service Open Threat Signaling
(DOTS) Signal Channel Specification", RFC 9132,
DOI 10.17487/RFC9132, September 2021,
<https://www.rfc-editor.org/info/rfc9132>.
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[Style] IANA YANG, "IANA YANG",
<https://github.com/llhotka/iana-yang>.
Author's Address
Mohamed Boucadair
Orange
35000 Rennes
France
Email: mohamed.boucadair@orange.com
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