Shepherd writeup

draft-ietf-straw-sip-traceroute-02 proto writeup

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet Standard, Informational, Experimental, or Historic)?

Intended status: Standards Track

Why is this the proper type of RFC?

The document contains normative procedures.

Is this type of RFC 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.

 In many deployments, the media for SIP-created sessions does not
  flow directly from the originating user's UAC to the answering
  user's UAS.  Often, SIP B2BUAs in the SIP signaling path also insert
  themselves in the media plane path by manipulating SDP, either for
  injecting media such as rich-ringtones or music-on-hold, or for
  relaying media in order to provide functions such as transcoding,
  IPv4-IPv6 conversion, NAT traversal, SRTP termination, media
  steering, etc.

  As more and more SIP domains get deployed and interconnect, the odds
  of a SIP session crossing such media-plane B2BUAs increases, as well
  as the number of such B2BUAs any given SIP session may go through.
  In other words, any given SIP session may cross any number of
  B2BUA's both in the SIP signaling plane as well as media plane.

  If failures or degradation occur in the media plane, it is difficult
  to determine where in the media path they occur.  In order to aid
  managing and troubleshooting SIP-based sessions and media crossing
  such B2BUAs, it would be useful to be able to progressively test the
  media path as it reaches successive B2BUAs with a test controlled in
  a single-ended way from the source UA.  A mechanism to perform
  media-loopback test sessions has been defined in [RFC6849], but it
  cannot be used to directly to test B2BUAs because typically the
  B2BUAs do not have an Address of Record (AoR) to be targeted, nor is
  it known a priori which B2BUAs will be crossed for any given

  For example, suppose calls from Alice to Bob have media problems.
  Alice would like to test the media path to each B2BUA in the path to
  Bob separately, to determine which segment has the issues.  Alice
  cannot target the B2BUAs directly for each test call, because she
  doesn't know what URIs to use to target them; nor would using such
  URIs guarantee the same media path be used as a call to Bob.  A
  better solution would be to make a test call targeted to Bob, but
  with a SIP traceroute-type mechanism that makes the call terminate
  at the B2BUAs, such that she can perform test sessions to test the
  media path to each downstream B2BUA.

  This document defines how such a mechanism can be employed, using
  the [RFC6849] mechanism along with the Max-Forwards SIP header field
  such that a SIP User Agent can make multiple test calls, each

 reaching a B2BUA further downstream.  Each B2BUA in the path that
  supports the mechanism in [RFC6849] would answer the media-loopback
  call, and thus the originating SIP UA can test the media path up to
  that B2BUA.

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 rough?

The WG path of this document was reasonably short and efficient.
Several technical comments were made during reviews and all were resolved with consensus.

There is consensus in the STRAW WG to publish this document.

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 guidelines and procedures in the document is based on input  and experience from the implementer community.


Who is the Document Shepherd?

Victor Pascual ( -- STRAW WG co-chair)

Who is the Responsible Area Director?

Richard Barnes <>

(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 is ready for publication

(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.


(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 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?


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


(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 as a whole understand and agree with it

(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.

idnits 2.13.01


 Checking boilerplate required by RFC 5378 and the IETF Trust (see

    No issues found here.

 Checking nits according to

    No issues found here.

 Checking nits according to :

    No issues found here.

 Miscellaneous warnings:

 -- The document date (March 11, 2014) is 29 days in the past.  Is this

 Checking references for intended status: Proposed Standard

    (See RFCs 3967 and 4897 for information about using normative references
    to lower-maturity documents in RFCs)

 == Missing Reference: 'RFC3261' is mentioned on line 185, but not
    'As currently defined in [RFC3261], the UAS half of a B2BUA does n...'

    Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--).

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

Not Applicable

(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.


(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 makes no request or reference to IANA

(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 makes no request to IANA

(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.

This document does not use formal language such as XML code, BNF rules or MIB definitions.