YANG Data Structure Extensions
draft-ietf-netmod-yang-data-ext-05

[Ballot comment]
Section 6. Recommend staying consistent with the standard YANG security considerations (https://trac.ietf.org/trac/ops/wiki/yang-security-guidelines) and at least include this following subset (or something like it) of the boiler plate language:

  The YANG module in this document defines an extension in the YANG data
  modeling language that will be imported and used by other modules.  When
  imported and used, the resultant schema will have data nodes that can
  be writable, or readable.  The access to such data nodes may be
  considered sensitive or vulnerable in some network environments.
  Write operations (e.g., edit-config) to these data nodes without
  proper protection can have a negative effect on network operations.

Section 7.3.  What purpose will this section serve when published?  Is seems like it could be removed.  The only use of the [1] reference is Appendix C which is supposed to be removed before publication.

[Ballot comment]
I don't have much to add, other than to agree with Alexey's comments on 2 addressbook entry examples, and Benjamin's "This does not mean a YANG data structure has to be used as a top-
  level protocol message or other top-level data structure." comment -- I too was confused by this...

[Ballot comment]
Section 1

  The "yang-data" extension from [RFC8040] has been copied here,
  renamed to "structure", and updated to be more flexible.  There is no

The Gen-Art reviewer had a good comment on this that should be acted
upon.

Section 2

  This does not mean a YANG data structure has to be used as a top-
  level protocol message or other top-level data structure.

I was confused by this until I got through Section 4, which (I think!)
clarified that I need a top-level extension directive to "declare the
named structure", but this is saying that once the structure is
declared, it can be placed anywhere in the tree as a "node of structure
type".  Perhaps we could add a few words here to clarify, e.g., "YANG
data structure, once defined," or "A YANG data structure can be used as
any other data type, in the rest of the module"?

Section 3

Do we need to say anything about how the child s under
structure/augment-structure get printed?  (I assume they get the same
handling as for the datastore tree, but could be wrong.)

  The new sections, including spaces conventions is:

      structure :

(I see four spaces between the column the paragraph starts in and the
column the "structure" keyword starts in, not two.)

  [augment-structure]
  [...]
            The sub-statements of this extension MUST follow the ABNF
          rules below, where the rules are defined in RFC 7950:

            [status-stmt]
            [description-stmt]
            [reference-stmt]
            1*(data-def-stmt / case-stmt)

Comparing to RFC 7950's augment-stmt, we see that when-stmt and
if-feature-stmt are not present; would those be used externally to the
augment-structure declaration if needed?

Section 6

I might consider adding a note that the data being modelled might have
its own security considerations, but there's a pretty good case that
this is already covered in RFC 7950 and thus would be redundant here.

Appendix A.1

Using last+first as the only naming options (and the list keys) is
perhaps a bit unfortunate, given, e.g.,
https://www.kalzumeus.com/2010/06/17/falsehoods-programmers-believe-about-names/
(which has been popularized several times on varous social-media sites
over the years).
I suppose it still suffices for the purposes of this example, though.

Appendix A.3, A.4

As Alexey notes, maybe have two address entries in the example so that the reader sees
the encoding of the list structure?

(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

The IANA Functions Operator has completed its review of draft-ietf-netmod-yang-data-ext-04. If any part of this review is inaccurate, please let us know.

The IANA Services Operator understands that, upon approval of this document, there are two actions which we must complete.

First, in the ns registry on the IETF XML Registry page located at:

https://www.iana.org/assignments/xml-registry/

a single, new namespace will be registered as follows:

ID: yang:ietf-yang-structure-ext
URI: urn:ietf:params:xml:ns:yang:ietf-yang-structure-ext
Filename: [ TBD-at-Registration ]
Reference: [ RFC-to-be ]

As this document requests registrations in a Specification Required (see RFC 8126) registry, we will initiate the required Expert Review via a separate request. Expert review will need to be completed before your document can be approved for publication as an RFC.

Second, in the YANG Module Names registry on the YANG Parameters registry page located at:

https://www.iana.org/assignments/yang-parameters/

a single, new YANG module will be registered as follows:

Name: ietf-yang-structure-ext
File: [ TBD-at-Registration ]
Maintained by IANA? N
Namespace: urn:ietf:params:xml:ns:yang:ietf-yang-structure-ext
Prefix: sx
Module:
Reference: [ RFC-to-be ]

While the YANG module name will be registered after the IESG approves the document, the YANG module file will be posted after the RFC Editor notifies us that the document has been published.

The IANA Services Operator understands that these are the only actions required to be completed upon approval of this document.

Note:  The actions requested in this document will not be completed until the document has been approved for publication as an RFC. This message is meant only to confirm the list of actions that will be performed.

Thank you,

Sabrina Tanamal
Senior IANA Services Specialist

The following Last Call announcement was sent out (ends 2019-11-04):

From: The IESG
To: IETF-Announce
CC: ibagdona@gmail.com, netmod-chairs@ietf.org, netmod@ietf.org, draft-ietf-netmod-yang-data-ext@ietf.org, joelja@gmail.com, Joel Jaeggli
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (YANG Data Structure Extensions) to Proposed Standard


The IESG has received a request from the Network Modeling WG (netmod) to
consider the following document: - 'YANG Data Structure Extensions'
  as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits final
comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2019-11-04. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the beginning of
the Subject line to allow automated sorting.

Abstract


  This document describes YANG mechanisms for defining abstract data
  structures with YANG.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-netmod-yang-data-ext/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-netmod-yang-data-ext/ballot/


No IPR declarations have been submitted directly on this I-D.

[Ballot comment]
A fine extension.  Just three editorial nits:

-- Section 1 —

  There is no
  assumption that a YANG data structure can only be used as a top-level
  abstraction, instead of nested within some other data structure.

It’s a little odd to use “instead of” after “there is no assumption”; I can’t explain it fully, but it feels odd to this native English speaker.  I suggest this:

NEW
  There is no
  assumption that a YANG data structure can only be used as a top-level
  abstraction, and it may also be nested within some other data structure.
END

  similar to the existing YANG "augment" statement.

Make it “similarly”.

— Section 1.1.1 —

  The following terms are defined in the Network Management Datastore
  Architecture (NMDA) [RFC8342].  and are not redefined here:

The period after the citation should be a comma.

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
  functionality.

  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.

Personnel

  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
disclosures.

  no

(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 https://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
thorough.

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.

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
  functionality.

  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.

Personnel

  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
disclosures.

  no

(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 https://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
thorough.

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.