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  - Standards Track is indicated on the title page. 

The document standardizes SDP Offer/Answer procedures for SCTP over DTLS and hence Standards Track is appropriate. 

(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.

The Stream Control Transmission Protocol (SCTP) is a transport protocol used to establish associations between two endpoints. SCTP can be used on top of the Datagram Transport Layer Security (DTLS) protocol, referred to as SCTP-over-DTLS.

This specification defines the following new Session Description Protocol (SDP) protocol identifiers (proto values): 'UDP/DTLS/SCTP' and 'TCP/DTLS/SCTP'.  This specification also specifies how to use the new proto values with the SDP Offer/Answer mechanism for negotiating SCTP-over-DTLS associations.

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 

Nothing in particular to note. The document has seen decent WG participation and no particular “roughness” in terms of consensus. 

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?

There are existing implementations of earlier versions of the document and those implementations are expected to be updated. The specification is required in order to use SDP for negotiating WebRTC data channels and hence is expected to see significant vendor adoption.

MIB Doctor, etc. review is Not Applicable. 


  Who is the Document Shepherd? Who is the Responsible Area

Flemming Andreasen is the Document Shepherd
Ben Campbell is the 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.

I have reviewed -19 in detail as well as the resulting changes in the -20 and -21 versions. The review includes ID-Nits check as well. The document is ready for publication. 

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

No. Several people have both contributed to and reviewed the document. 

(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.


(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.

No such 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.

Each author has confirmed.

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

No IPR disclosure.

(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 document has solid consensus in the WG with several people having participated in both the development and review of the document. 

(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

ID nits check yields a few warnings and comments, however none of them are real issues:
-	IPv6 address examples are not necessary since IP version differences are immaterial to the purpose of the specification.
-	Section references are using square brackets, which triggers a few (false) warnings

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


(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?

There are 4 such references which plans as follows:

draft-ietf-mmusic-4572-update is ready for Publication Request

draft-ietf-mmusic-dtls-sdp is expected to proceed towards Publication Request within a few months 

draft-ietf-tsvwg-sctp-dtls-encaps is with the RFC Editor, where it is in MISSREF state waiting for draft-ietf-tsvwg-sctp-ndata. That particular draft is currently in WGLC and is expected to be with the IESG before the next IETF Meeting (IETF 98, March 26, 2017).  

draft-ietf-mmusic-sdp-mux-attributes is with the RFC Editor where it is in MISSREF state waiting for another MMUSIC document (draft-ietf-mmusic-sdp-bundle-negotiation) that is expected to proceed towards Publication Request within a few months. 

The draft is furthermore requesting that its publication waits for draft-ietf-rtcweb-data-protocol, which is currently with the RFC Editor in MISSREF state. That document has references to JSEP (draft-ietf-rtcweb-jsep) and two RTCWeb security documents. The RTCWeb WG chairs aim to get these publication requested before IETF 98, however JSEP may require further discussion at that meeting to resolve an issue. 

(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. 


(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).

IANA Considerations have been reviewed per the above, which resulted in some document changes reflected in the latest version of the document.  

(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.

The document defines a new IANA registry with a registration policy of "First Come First Served" and hence no designated expert is required. 

(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.

ABNF has been verified with Bill Fenner's ABNF Parser.