As required by RFC 4858, this is the current template for the Document
Changes are expected over time. This version is dated 24 February 2012.
(1) What type of RFC is being requested (BCP, Proposed Standard,
Internet Standard, Informational, Experimental, or Historic)? Why
is this the proper type of RFC? Is this type of RFC indicated in the
title page header?
A Proposed Standard is being requested. A proposed standard is needed to
ensure interoperability. The title page header indicates that it is Standards Track document.
(2) The IESG approval announcement includes a Document Announcement
Write-Up. Please provide such a Document Announcement Write-Up. Recent
examples can be found in the "Action" announcements for approved
documents. The approval announcement contains the following sections:
This document defines a YANG extension statement that allows for
defining metadata annotations in YANG modules. The document also
specifies XML and JSON encoding of annotations and other rules for
annotating instances of YANG data nodes.
Working Group Summary
There has been some controversy regarding the fact that metadata
annotations are defined using a YANG extension, which means that they
are by definition optional to implement. On the other hand, introducing
a new built-in YANG statement was considered a big change that's not
suited for inclusion in the minor (1.1) revision of YANG.
In the past, vendors of management software and networking devices
introduced a number of proprietary metadata annotations for various
purposes. This document allows for including information about
annotations in YANG data models so that standard annotations can be
defined in an interoperable way, and in both supported encodings (XML
The RESTCONF protocol document [draft-ietf-netconf-restconf] has a
normative reference to this document for the encoding of metadata.
Also, the widely used tool `pyang` has already been updated to support
The Shepherd is Kent Watsen. The AD is Benoit Claise.
(3) Briefly describe the review of this document that was performed by
the Document Shepherd. If this version of the document is not ready
for publication, please explain why the document is being forwarded to
The Document Shepherd went through the checklist listed here:
(4) Does the document Shepherd have any concerns about the depth or
breadth of the reviews that have been performed?
(5) Do portions of the document need review from a particular or from
broader perspective, e.g., security, operational complexity, AAA, DNS,
DHCP, XML, or internationalization? If so, describe the review that
No portions of the document have been flagged as needing to be reviewed
from a particular or from broader perspective.
(6) Describe any specific concerns or issues that the Document Shepherd
has with this document that the Responsible Area Director and/or the
IESG should be aware of? For example, perhaps he or she is uncomfortable
with certain parts of the document, or has concerns whether there really
is a need for it. In any event, if the WG has discussed those issues and
has indicated that it still wishes to advance the document, detail those
The Document Shepherd has no specific concerns or issues with this document.
(7) Has each author confirmed that any and all appropriate IPR
disclosures required for full conformance with the provisions of BCP 78
and BCP 79 have already been filed. If not, explain why.
Yes, on October 12th.
(8) Has an IPR disclosure been filed that references this document?
If so, summarize any WG discussion and conclusion regarding the IPR
No IPR disclosure has been filed.
(9) How solid is the WG consensus behind this document? Does it
represent the strong concurrence of a few individuals, with others
being silent, or does the WG as a whole understand and agree with it?
The design goals for metadata encoding were extensively discussed
in the early phases of this document, and there was a strong WG consensus.
The document fulfills all the requirements.
(10) Has anyone threatened an appeal or otherwise indicated extreme
discontent? If so, please summarise the areas of conflict in separate
email messages to the Responsible Area Director. (It should be in a
separate email because this questionnaire is publicly available.)
No one has threatened an appeal otherwise indicated extreme discontent.
(11) Identify any ID nits the Document Shepherd has found in this
document. (See https://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
== Outdated reference: A later version (-11) exists of
== Outdated reference: A later version (-07) exists of
(12) Describe how the document meets any required formal review
criteria, such as the MIB Doctor, media type, and URI type reviews.
This document has been reviewed by members of the YANG Doctors group.
(13) Have all references within this document been identified as
either normative or informative?
Yes, all references have been partitioned into these two groupings.
The groupings seem okay, except for two issues:
1) I think it just a bit strange that it has normative references to both
RFC 6020 and 6020bis. The reference to 6020 is for an IANA Consideration
request to update the "YANG Module Names” registry, originally defined
in 6020, but 6020bis will do the same.
2) The document has an Informative reference to RFC 6241 (NETCONF),
though it uses it for defining terms used throughout the document.
To me, this seems to make it a Normative reference.
(14) Are there normative references to documents that are not ready for
advancement or are otherwise in an unclear state? If such normative
references exist, what is the plan for their completion?
There are no normative references to documents and aren’t ready for advancement.
(15) Are there downward normative references references (see RFC 3967)?
If so, list these downward references to support the Area Director in
the Last Call procedure.
There are no downward normative references in this document.
(16) Will publication of this document change the status of any
existing RFCs? Are those RFCs listed on the title page header, listed
in the abstract, and discussed in the introduction? If the RFCs are not
listed in the Abstract and Introduction, explain why, and point to the
part of the document where the relationship of this document to the
other RFCs is discussed. If this information is not in the document,
explain why the WG considers it unnecessary.
Publication of this document will not change the status of any
(17) Describe the Document Shepherd's review of the IANA considerations
section, especially with regard to its consistency with the body of the
document. Confirm that all protocol extensions that the document makes
are associated with the appropriate reservations in IANA registries.
Confirm that any referenced IANA registries have been clearly
identified. Confirm that newly created IANA registries include a
detailed specification of the initial contents for the registry, that
allocations procedures for future registrations are defined, and a
reasonable name for the new registry has been suggested (see RFC 5226).
This document’s IANA Considerations section registers a URI to the
"IETF XML registry" [RFC3688] and a YANG module in the "YANG Module
Names” registry [RFC6020]. Both registrations appear proper.
(18) List any new IANA registries that require Expert Review for future
allocations. Provide any public guidance that the IESG would find
useful in selecting the IANA Experts for these new registries.
This document does not define any new IANA registries.
(19) Describe reviews and automated checks performed by the Document
Shepherd to validate sections of the document written in a formal
language, such as XML code, BNF rules, MIB definitions, etc.
Extracting the "ietf-yang-metadata.yang” module from the document
and running `pyang --ietf --strict --lint` on it produced no errors.
The ABNF in Section 5.2.1 passed visual inspection. The examples
throughout the document passed visual inspection.