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?

Proposed Standard, which is indicated in the title page header.  

(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

  Relevant content can frequently be found in the abstract 
  and/or introduction of the document. If not, this may be 
  an indication that there are deficiencies in the abstract 
  or introduction.

This document defines the 608 (Rejected) SIP response code, which informs a calling party that an intermediary has rejected their call attempt. This document also extends the Call-Info header field so that the caller may contact the blocking party if the rejection was in error. The 608 response code addresses the use case of call rejection by a call analytics engine or other automated process. This contrasts with the 607 (Unwanted) SIP response code, which is sent by a SIP user agent when a human indicates that the call was not wanted [RFC8197].

Working Group Summary

  Was there anything in WG process that is worth noting? For 
  example, was there controversy about particular points or 
  were there decisions where the consensus was particularly 

The document is of interest to the STIR (Secure Telephone Identity Revisited) WG, but discussions were (mostly) kept to the SIPCORE mailing list since the document covers a SIP extension. Sometimes cross-posting was not successful and some discussions occurred only on the STIR mailing list. All feedback that was discussed on the STIR mailing list was incorporated into the document, however. 

Document Quality

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

One of the authors (Bhavik Nagda) implemented this solution in Kamailio, which is an open source SIP server. The implementation can be found at There are also governmental agencies that are interested in the 608 response code feature. 

Reviewers and their contributions have been called out in the Acknowledgements section. Tolga Asveren provided substantial feedback on interoperability and security considerations. 


  Who is the Document Shepherd? 

  Jean Mahoney

  Who is the Responsible Area Director?

  Adam Roach

(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 checked that all feedback provided on both the STIR and SIPCORE lists was incorporated or otherwise addressed in document updates. This document is ready to be forwarded to the IESG. 

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

The document shepherd is satisfied with the breadth and depth of reviews performed by the working group. 

(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.

None required. 

(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 Document Shepherd has no specific concerns or issues with the draft. 

(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.

The authors confirmed that they have no IPR to declare on this draft.

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

No IPR disclosures have 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 draft was adopted by the working group with lots of +1s. It received thorough feedback from a handful of WG participants in both STIR and SIPCORE. 


(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 indicated any discontent with the draft. 

(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

idnits 2.15.01 was run, and no issues were found. The Shepherd checked the draft against  No issues were found with the draft.

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

Documents that specify new JSON Web Token claims must pass through an Expert Review system [RFC7519]. The document shepherd sent email to ( In their roles as Designated Experts, Mike Jones and Brian Campbell approved the registration request. 

The updates made to the SIP Parameters IANA registries by this document fall under the registration procedures of either "RFC Required" or "IETF Review" [RFC5226], so the typical review process for a standards-track document is sufficient. 

(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?

All normative references are to published RFCs.

(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.

(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 does not change the status of any published RFCs.

(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).

The IANA Considerations section clearly identifies the appropriate sub-registries within the "Session Initiation Protocols" registry, and describes the new rows to add to those subregistries.  

The IANA Considerations section clearly identifies the "JSON Web Token Claims" sub-registry within the "JSON Web Token (JWT)" registry, and describes the new row to add to the subregistry. 

(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.

There is no formal language defined in this document.