Shepherd writeup

As required by RFC 4858, this is the Document Shepherd Write-Up
for: IPv6 Performance and Diagnostic Metrics (PDM) Destination Option

The version of this template 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

(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:

To assess performance problems,  measurements based on optional
sequence numbers and timing may be enabled in packets of a
particular flow using a new Destination Options Header.  Such
measurements may be interpreted in real-time or after-the-fact. 
This document gives a specification of the existing IPv6 
Destination Option extension header, 
called the Performance and Diagnostic Metrics (PDM) Destination
Option. The document also provides the field limits, calculations,
and usage of the PDM in measurement.

Working Group Summary:

After years of discussion, consideration, and revision, the working
group adopted the draft and then moved smoothly to consensus in
another year, aided by the implementation of the option in Free BSD.

Document Quality:

This document was reviewed at many occasions by the measurement and
IPv6 communities. 

Who is the Document Shepherd? Who is the Responsible Area Director?

The document shepherd is Al Morton (was formerly Bill Cerveny). 
Spencer Dawkins 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.
Bill Cerveny provided an editorial review, and his comments were 
addressed in version 03. Al Morton reviewed the document many times
in WG review and Last Call, and his comments have been shared with
the authors.

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

No.  There have been reviews by experts in v6ops, 6man and IPPM.

(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?


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

IPR was disclosed in the form of an early filing on 
Since the provisional filing (2013) was not followed-up, the time limit has 
expired and the provisional filing is no longer valid. See:

The current filing
reflects this status accurately.

There is no evidence of IPPM WG discussion of IPR revealed in list
search, and only one message on v6ops:
(which indicates an issue with the licensing terms of another 
draft, not PDM.)

(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?

Among the individuals who have reviewed and provided comments,
there now appears to be agreement with the content and concurrence
that the draft is ready.

(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.

The Abstract appears after the ToC, which is an odd order of front-matter.

(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).

The IANA section was revised as a result of review with the
Document Shepherds(both past and present), and now meets these 

(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.


(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.

Not applicable

Shepherd's (editorial) comments (Al, on version 03)

112 ... An
113	   implementation of the existing IPv6 Destination Options extension
114	   header, the Performance and Diagnostic Metrics (PDM) Destination
115	   Options extension header has been proposed in a companion document.
acm: It would be good to provide a reference to the 
companion document here, if possible.

Also, "proposed" appears 5 times in the text, 
it's more accurate to say "defined" now that this
doc has reached WG consensus (at least) and will soon
be an RFC.

1129	8 Security Considerations

1131	   The PDM MUST NOT be changed dynamically via packet flow as this
1132	   creates a possibility for potential security violations or DoS
1133	   attacks by numerous packets turning the header on and off.
acm: does this mean 
The *presence or omission of* 
PDM MUST NOT be changed dynamically via packet flow as...