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. The document obsoletes RFC 5245, which itself is a 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

This document describes Session Description Protocol (SDP) Offer/Answer procedures for carrying out Interactive Connectivity Establishment (ICE) between the agents.

This document obsoletes RFC 5245.

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 has been in progress since 2013 (as a companion document to the now published RFC 8445). The document has generally been non-controversial, however more recently (starting in July 2018 at IETF 102), the lack of DNS and mDNS support was raised as a concern by a few people. A consensus call to leave it out was made at IETF 102. Recent MMUSIC mailing list discussions raised the issue again, however in the interest of moving the document forward, the previous consensus was reconfirmed, with provisions in this document to enable DNS procedures to be added as an extension later on. 

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?

The document obseletes RFC 5245, which has a number of existing implementations. The document is one of the deliverables needed by RTCWeb, and as such is expected to see significant implementation. 

Roman Shpount in particular has been instrumental in moving this document forward by resolving a variety of issues and contributing specific text proposals. Christer Holmberg and Adam Roach have been very helpful as well. 


  Who is the Document Shepherd? Who is the Responsible Area

Flemming Andreasen is the Document Shepherd

Adam Roach 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.

I have reviewed -16, -18 and -30 in detail as well as subsequent changes in the current version (-35). The document is ready for publication at this point. 

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

No concerns. The document itself has received several reviews, incl. by a couple of people that are familiar with both this document and the updated ICE specification (RFC8445). 

(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.


(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.


It should be noted however, that while no IPR disclosures have been filed on this document, IPR disclosures were filed on the original RFC 5245 and the updated ICE companion document (RFC 8245). See

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

N/A (but see above)

(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 WG consensus is solid. 

(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

The Shepherd review has not revealed any real issues, however the I-D nits tool provides a few warnings:
- All reference warnings are false positives. 
- The pre-RFC5378 disclaimer is currently needed – the original author of RFC 5245 was recently contacted to see if we can obtain the BCP78 rights to the IETF trust (TBD)

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

N/A. The document only defines/updates SDP attributes and the ice-options registry. 

(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. 


(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.

Yes. The document obsoletes RFC 5245, as indicated on the Title page, Abstract and Introduction of the document. 

(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).

Confirmed. The Shepherd has reviewed the IANA Considerations section for consistency with the body of the document and the above requirements. 

(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.

N/A (the ice-options registry exists already)

(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.

I have performed a detailed review of -30 and subsequent changes in -35 (current version). ABNF has been checked (successfully) with Bill Fenner’s ABNF parser.