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?

This document is intended to be a Proposed Standard 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:

Technical Summary

  This document specifies a data model for client and server implementations of the Two-Way Active Measurement Protocol (TWAMP).
  The TWAMP data model is described through Unified Modeling Language (UML) class diagrams and formally specified using YANG.

  The Two-Way Active Measurement Protocol (TWAMP) [RFC5357] is used to measure network performance parameters such as latency, bandwidth,
  and packet loss by sending probe packets and measuring their experience in the network.  To date, TWAMP implementations do not come
  with a standard management framework and, as such, configuration depends on proprietary mechanisms developed by the corresponding
  TWAMP vendor.  This document addresses this gap by formally specifying the TWAMP data model using YANG.

Working Group Summary

  This document was presented and discussed in IETF96, IETF97, IETF98 and IETF99.  There has also been discussion on the email list.   
  There were questions raised as to the inclusion of TWAMP Light in this document.  The consensus was that TWAMP Light is not 
  adequately specified as a protocol.  This is the precursor to creating a YANG model.

Document Quality

  The document was reviewed and comments were provided in both the IETF meetings and on the IPPM WG mailing list. 
  A YANG doctors review was requested for the YANG module in the document and it was provided by Jan Lindblad.

Are there existing implementations of the protocol? Have a significant number of vendors indicated their plan to 
implement the specification? 

   AT&T has an implementation.  Viavi was working on an implementation for testing Ethernet. 

Are there any reviewers that merit special mention as having done a thorough review, e.g., one that resulted in important changes or a conclusion
that the document had no substantive issues? If there was a MIB Doctor, Media Type or other expert review, what was its course (briefly)? In the 
case of a Media Type review, on what date was the request posted?

   A YANG doctors review was requested for the YANG module in the document and it was provided by Jan Lindblad.  A number of the suggestions were implemented. 


  The Document Shepherd is Nalini Elkins.  The Responsible Area Director is Spencer Dawkins.

(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 followed the progression of the document through the WG and has reviewed the email chains as well as the review of the
   Yang doctor. As this time, it appears the document has addressed comments other than those regarding the inclusion of TWAMP Light, because there will
   be a separate document by the commentor to address TWAMP Light.  As a document shepherd I believe the document is ready for publication.

   There were quite a few comments from the Yang doctors.  I have verified that all comments were addressed. These include comments regarding
   the YANG model, stream characteristics, and operator commands.


(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 took place.

    This document is concerned with TWAMP and YANG.  Both areas have been addressed in detail.

(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.

I have no 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.

   Yes, each author has so confirmed.

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

   Since this is a YANG model for RFC 5357, the IPR disclosed for TWAMP is applicable:

(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?   

   There appears to be rough consensus from that portion of the WG which is involved with TWAMP and YANG.  Not all WG members work in that area so
   they are silent.  

(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.) 


(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 thorough.

Miscellaneous warnings:

  == Line 651 has weird spacing: '...riority    uin...'

  == Line 684 has weird spacing: '...m-index    uin...'

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

   A YANG doctor review has been done.

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


(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. 

   See idnits

(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.


(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 registers a URI in the IETF XML registry [RFC3688].   The format is correct. 

(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.

   There are no 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.

  YANG validation Passed:
From the Datatracker page, if you click on the Yin/YANG symbol, you get:
xym 0.4:
Extracting 'ietf-twamp@2017-02-22.yang'
pyang 1.7.3: pyang --verbose --ietf -p {libs} {model}:
No validation errors
yanglint 0.13.69: yanglint --verbose -p {rfclib} -p {draftlib} -p {tmplib} {model} -i:
No validation errors