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Shepherd writeup

(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?

As the draft header shows, the 6LO working group requests the category of this
RFC to be Proposed Standard, because it defines a new extension mechanism for
RFC 4944 dispatch codes, and requires the creation of several new IANA

(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:

The abstract is a good technical summary. "This specification updates RFC 4944
to introduce a new context switch mechanism for 6LoWPAN compression, expressed
in terms of Pages and signaled by a new Paging Dispatch."

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?

There was minimal controversy and rough consensus appears to have been
achieved. It may or may not be worth noting that I was among the dissenters who
criticized this draft. See the section below about document shepherd concerns
for more details.

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 at least two independent open-source implementations, i.e. OpenWST
and Kontiki, and both have been tested for interoperability at an ETSI plugfest

The technical language of the specification is quite good, and I believe it is
ready for submission to the RFC editor.


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

Document Shepherd: james woodyatt <>
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 read the draft for comprehension several times and followed its edits.
As mentioned above, I understand the draft sufficiently to make critical
remarks about it on the working group list.

The draft 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 concerns. I believe it has been adequately reviewed.

(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.

I would caution the IESG that the increase in operational complexity must be
weighed against energy savings compared to the alternatives. The IESG may
choose to review that decision, but the issue is subtle and the experts in the
working group were careful in their considerations.

(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.

My concern, which I expressed on the working group list, is that the
introduction of the paging dispatch mechanism changes 6LoWPAN compression into
a language where the semantic meaning of a dispatch code in any particular
6LoWPAN message depends on the context in which the message appears. Therefore,
when a message is removed from its context, i.e. by decapsulating it from
another enclosing 6LoWPAN message that used one of the paging dispatch codes,
the semantic attributes of that dispatch code are lost unless the previously
encapsulated message is accompanied by an external record of the dispatch page
number that applied to it in its encapsulated context. This increase in
operational complexity didn’t seem to me like it was worth the energy savings
to be gained by not having to send a dispatch extension code for every dispatch
other than those for which codes currently exist. I was decidedly in the
minority on that judgment.

In any case, my criticisms were entertained on the working group list, my
objections heard and considered in fairness. The consensus of the working group
is that the additional operational complexity of introducing the paging state
variable in the 6LoWPAN parser is worth the energy savings to be had by not
using a more verbose grammar for extending the dispatch code space while
preserving the statelessness of the parser. I have no strong counter-argument
against this judgment.

While I’m still not a fan of this draft, I didn’t object to its adoption by the
working group, and I don’t object now to its publication.

(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 lead author has confirmed that no IPR disclosures are required for BCP 78
and BCP 79.

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

No IPR disclosure has 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?

There is broad consensus behind this draft. It represents the strong
concurrency of many individuals with a small number of dissenters in the “no
objections” camp.

(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.)

Nobody is threatening an appeal or expressing serious discontent. I think I’m
probably the loudest dissenter, and I have no objections to the publication of
this 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 thorough.

The ID nits tool is raising some false flags. None of the nits are
show-stoppers. The draft is ready for the RFC editor.

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

There are no formal review requirements.

(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 documents.

(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


(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.

As both the header and the abstract indicate, this draft is an Update to RFC

(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).

I reviewed the IANA considerations section for correctness and consistency with
the body of the draft. Approval of the editorial decision to use a textual
description of the contents in the new Page 1 registry instead of an explicit
listing of the Page 1 registry content is left to the RFC editor.

(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.

There are no new IANA registries that require Expert Review for future

(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 are no instances of embedded texts in the draft that are written in a
formal language.

—james woodyatt <>