Shepherd writeup

As required by RFC 4858, this is the current template for the Document 
Shepherd Write-Up.

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?

draft-ietf-netmod-yang-data-ext is a standards track document intending to go into a status of proposed standard. 

(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:

Technical Summary

   There is a need for standard mechanisms to allow the definition of
   abstract data that is not intended to be implemented as configuration
   or operational state.  The "yang-data" extension statement from RFC
   8040 [RFC8040] was defined for this purpose but it is limited in its

   The "yang-data" extension from [RFC8040] has been copied here,
   renamed to "structure", and updated to be more flexible. 

Working Group Summary

  Working group action on this document was relatively uncontroversial. The limitations of the RFC 8040 data model extension respecting extensibility are well understood.

Document Quality

  The document as recieved several excellent reviews from implmentors. Authors and reviewers are part of the yang directorate and are participants in the development and extension of yang.


  Joel Jaeggli is the document shepherd. Ignas Bogdonas is the responsible area director.

(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 IESG.

  The document shepherd has reviewed the document as part of the working group last call.

(4) Does the document Shepherd have any concerns about the depth or
breadth of the reviews that have been performed?

  Subsequent to the publication of draft 4 and WG the shepherd has no major concerns.

(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
took place.

  Formal review from the yang directorate has not been requested due to the large overlap between authors and reviewers and the yang directorate. we have excellent community converage at this point within netmod.

(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
concerns here.

  The shepherd has no specific concerns.

(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.

  NETMOD WG last calls directly ask questions about IPR disclosure. No disclusures have been filed and the authors have confirmed not claims accordingly.

(8) Has an IPR disclosure been filed that references this document?
If so, summarize any WG discussion and conclusion regarding the IPR


(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?

  Working group consensus was solidly in favor of advancing the document. The WGLC dicussion was light as the document appears ready for publication.

(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 appeals are threatened or anticipated.

(11) Identify any ID nits the Document Shepherd has found in this
document. (See and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be

Nits produces two superfical warnings. 

  One, the update for yang tree diagrams is not noted in the abstract. Tree diagrams is not a protoctol specification and is intended to be regularly extended by yang language extensions which is what this is.

  the second incorrectly identfies a reference on line 680

(12) Describe how the document meets any required formal review
criteria, such as the MIB Doctor, media type, and URI type reviews.

  Normal expectation  would be for a yang doctorcs to review this document. At this point asking for further reviews from yang doctors would be dupliciative effort.

(13) Have all references within this document been identified as
either normative or informative?

  references are identified as normative and informative.

(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?

All normative references are published.

(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. 

  Normative references are to standards track documents or BCPs.

(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.

  This document updates but does not change the status of any previous documents.

(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 8126).

  This document registers a URI in the IETF XML registry and a yang module in the yang modules name registry. These are well understood actions which standards actions may perform.

(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.

  No new iaana registries are created.

(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.

  The ietf-yang-structure-ext module extracts and validates.