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Shepherd writeup

# Document Shepherd Write-Up for Group Documents

*This version is dated 4 July 2022.*

Thank you for your service as a document shepherd. Among the responsibilities is
answering the questions in this write-up to give helpful context to Last Call
and Internet Engineering Steering Group ([IESG][1]) reviewers, and your
diligence in completing it is appreciated. The full role of the shepherd is
further described in [RFC 4858][2]. You will need the cooperation of the authors
and editors to complete these checks.

Note that some numbered items contain multiple related questions; please be sure
to answer all of them.

## Document History

1. Does the working group (WG) consensus represent the strong concurrence of a
   few individuals, with others being silent, or did it reach broad agreement?
   The consensus was mainly among a small group of individuals, but that is
   mostly standard operating procedure for the STIR working groups. Active 
   participants comprise a small number of industry experts.
   Note: The primary consumers of the technologies collectively known as 
   STIR are telecom SDOs that create profiles specific to their 
   constituencies, for example, the ATIS/SIP Forum IP-NNI task force creates
   profiles of STIR as part of the SHAKEN framework for US telephone network
2. Was there controversy about particular points, or were there decisions where
   the consensus was particularly rough?
   There have been concerns raised (mostly in venues other than STIR) about the
   potential for the substitution attack described in RFC 8816 section 7.4 could
   be a problem. There have been additional concerns raised about privacy
   implications of third-party Call Processing Services (CPS). Those concerns 
   mainly applied to proposals that do not conform to this draft, which mitigates
   those concerns by placing the CPS at of one of the parties to a 

3. Has anyone threatened an appeal or otherwise indicated extreme discontent? If
   so, please summarize 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.)
   There have been no threats of appeal or indications of discontent.

4. For protocol documents, are there existing implementations of the contents of
   the document? Have a significant number of potential implementers indicated
   plans to implement? Are any existing implementations reported somewhere,
   either in the document itself (as [RFC 7942][3] recommends) or elsewhere
   The shepherd is aware of multiple non-public implementation efforts, but
   is not aware of any publicly available reports.

## Additional Reviews

5. Do the contents of this document closely interact with technologies in other
   IETF working groups or external organizations, and would it therefore benefit
   from their review? Have those reviews occurred? If yes, describe which
   reviews took place.
   In the shepherd's opinion, the normal directorate reviews will be sufficient.

6. Describe how the document meets any required formal expert review criteria,
   such as the MIB Doctor, YANG Doctor, media type, and URI type reviews.
   The draft does not specify models, media types, URIs, etc., that
   would trigger the need for formal expert reviews.

7. If the document contains a YANG module, has the final version of the module
   been checked with any of the [recommended validation tools][4] for syntax and
   formatting validation? If there are any resulting errors or warnings, what is
   the justification for not fixing them at this time? Does the YANG module
   comply with the Network Management Datastore Architecture (NMDA) as specified
   in [RFC 8342][5]?
   The draft does not specify a YANG module.

8. Describe reviews and automated checks performed to validate sections of the
   final version of the document written in a formal language, such as XML code,
   BNF rules, MIB definitions, CBOR's CDDL, etc.
   The draft does not use formal languages that would trigger the need for 
   checks. idnits 2.17.1 mentions the normative downref described later
   in this writeup, but otherwise finds no material issues.

## Document Shepherd Checks

9. Based on the shepherd's review of the document, is it their opinion that this
   document is needed, clearly written, complete, correctly designed, and ready
   to be handed off to the responsible Area Director?
   The shepherd is of the opinion that this draft is ready to be handed off
   to the responsible area director.

10. Several IETF Areas have assembled [lists of common issues that their
    reviewers encounter][6]. For which areas have such issues been identified
    and addressed? For which does this still need to happen in subsequent
    The document does not fall afoul of the issues listed for the ART area.
    While some issues in the SEC area list may apply, the shepherd believes
    they have had sufficient review by security experts who actively 
    participate in the STIR working group.

11. What type of RFC publication is being requested on the IETF stream ([Best
    Current Practice][12], [Proposed Standard, Internet Standard][13],
    [Informational, Experimental or Historic][14])? Why is this the proper type
    of RFC? Do all Datatracker state attributes correctly reflect this intent?
    The intended status is Proposed Standard. This is the proper status because
    the draft specifies how to implement an interoperable service. It contains
    normative requirements which, if ignored, could impact the operation and
    security of the service. The intended status is correctly indicated in the
    data tracker.
    Note that earlier versions were labeled as informational. The working group
    agreed to change the status to Proposed Standard for the reasons listed
    above. This change is reflected in version 5.

12. Have reasonable efforts been made to remind all authors of the intellectual
    property rights (IPR) disclosure obligations described in [BCP 79][7]? To
    the best of your knowledge, have all required disclosures been filed? If
    not, explain why. If yes, summarize any relevant discussion, including links
    to publicly-available messages when applicable.
    There are no IPR disclosures. The author has confirmed that there is no
    undisclosed IPR that he is aware of.

13. Has each author, editor, and contributor shown their willingness to be
    listed as such? If the total number of authors and editors on the front page
    is greater than five, please provide a justification.

14. Document any remaining I-D nits in this document. Simply running the [idnits
    tool][8] is not enough; please review the ["Content Guidelines" on][15]. (Also note that the current idnits tool generates
    some incorrect warnings; a rewrite is underway.)
    The only material nit of which the shepherd is aware is the normative
    downref described in 17.

15. Should any informative references be normative or vice-versa? See the [IESG
    Statement on Normative and Informative References][16].
    The references are correctly categorized.

16. List any normative references that are not freely available to anyone. Did
    the community have sufficient access to review any such normative
    All normative references are to IETF RFCs.

17. Are there any normative downward references (see [RFC 3967][9] and [BCP
    97][10]) that are not already listed in the [DOWNREF registry][17]? If so,
    list them.
    There is a normative reference to an informational RFC: RFC 8816. This is
    appropriate because this draft describes a standard that realizes parts
    of the architecture defined in RFC 8816. That RFC is necessary reading
    to fully understand this draft. In particular, there are security
    considerations described in that RFC that implementors of this draft
    should understand. This downref should be called out in the IETF
    last call announcement.

18. Are there normative references to documents that are not ready to be
    submitted to the IESG for publication or are otherwise in an unclear state?
    If so, what is the plan for their completion?
    All normative references are to published RFCs.

19. Will publication of this document change the status of any existing RFCs? If
    so, does the Datatracker metadata correctly reflect this and are those RFCs
    listed on the title page, in the abstract, and discussed in the
    introduction? If not, explain why and point to the part of the document
    where the relationship of this document to these other RFCs is discussed.
    This draft does not change the status of any RFC.

20. 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 aspects of the document requiring IANA assignments are
    associated with the appropriate reservations in IANA registries. Confirm
    that any referenced IANA registries have been clearly identified. Confirm
    that each newly created IANA registry specifies its initial contents,
    allocations procedures, and a reasonable name (see [RFC 8126][11]).
    The draft makes no requests of IANA.

21. List any new IANA registries that require Designated Expert Review for
    future allocations. Are the instructions to the Designated Expert clear?
    Please include suggestions of designated experts, if appropriate.
    The draft makes no requests of IANA.