IPv6 over Low-Power Wireless Personal Area Network (6LoWPAN) Paging Dispatch
draft-ietf-6lo-paging-dispatch-05

(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

IANA has completed its review of draft-ietf-6lo-paging-dispatch-04. If any part of this review is inaccurate, please let us know.

We understand that this document is adding a column called "Page" and a new Header Type ("Page switch") to the Dispatch Type Field registry at http://www.iana.org/assignments/_6lowpan-parameters. This document will also be listed as an additional registration for the registry itself.

Because this is a Specification Required registry, IANA must request that the IESG designate an expert to review the new registration.

The updated registry will read as follows (note: in the registry, the Page column will be placed between the Bit Patter and Header Type columns):

Bit Pattern    Header Type    Page    Reference
00 xxxxxx NALP - Not a LoWPAN frame 0    [RFC4944]
00 xxxxxx Unassigned    1-15
01 000000 Reserved as a replacement value for ESC    0    [RFC6282]
01 000000 Unassigned    1-15
01 000001 IPv6 - uncompressed IPv6 Addresses    0    [RFC4944]
01 000001 Unassigned    1-15
01 000010 LOWPAN_HC1 - LOWPAN_HC1 compressed IPv6    0 [RFC4944]
01 000010 Unassigned    1-15
01 000011 LOWPAN_DFF    0    [RFC6971]
01 000011 Unassigned    1-15
01 000100 through 01 001111 reserved for future use
01 010000 LOWPAN_BC0 - LOWPAN_BC0 broadcast    0    [RFC4944]
01 010000 Unassigned 1-15
01 010001 through 01 011111 reserved for future use
01 1xxxxx         LOWPAN_IPHC    0-1    [RFC6282]
01 1xxxxx Unassigned    2-15
10 xxxxxx MESH - Mesh header    0    [RFC4944]
10 xxxxxx Unassigned    1-15
11 000xxx FRAG1 -- Fragmentation Header (first)    0    [RFC4944]
11 000xxx Unassigned    1-15
11 001000 through 11 011111 reserved for future use
11 100xxx         FRAGN -- Fragmentation Header (subsequent)    0    [RFC4944]
11 100xxx         Unassigned    1-15
11 101000 through 11 101111 reserved for future use
11 11xxxx        Page switch    0-15    [this document]

Note:  The actions requested in this document will not be completed until the document has been approved for publication as an RFC. This message is only to confirm what actions will be performed. 

Thank you,

Amanda Baber
IANA Lead Specialist
ICANN

[Ballot comment]
I found this text

  A Page (say Page N) is said to be active once the Page N Paging
  Dispatch is parsed, and as long as no other Paging Dispatch is
  parsed.
 
somewhat unclear. Is it saying

  A Page (say Page N) is said to be active once the Page N Paging
  Dispatch is parsed, and remains active until another Paging
  Dispatch is parsed.
 
?

I wasn't quite sure what "so far" meant in this text (and temporal references in RFCs that live forever are somewhat confusing, anyway).

      As a result, there is no need so far for restoring the Page 0
      parsing context after a context was switched to Page 1, so the
      value for the Page 0 Paging Dispatch of 11110000 may not actually
      occur in those packets that adhere to 6LoWPAN specifications
      available at the time of writing this specification.
     
Would this be just as correct with "so far" deleted, or am I not understanding the point you're making?

Thanks for explaining why you're choosing "Specification Required" as your IANA policy.

The following Last Call announcement was sent out:

From: The IESG
To: "IETF-Announce"
CC: 6lo-chairs@ietf.org, "james woodyatt" , draft-ietf-6lo-paging-dispatch@ietf.org, suresh.krishnan@ericsson.com, jhw@nestlabs.com, 6lo@ietf.org, aretana@cisco.com
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (6LoWPAN Paging Dispatch) to Proposed Standard


The IESG has received a request from the IPv6 over Networks of
Resource-constrained Nodes WG (6lo) to consider the following document:
- '6LoWPAN Paging Dispatch'
  as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits
final comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2016-09-29. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the
beginning of the Subject line to allow automated sorting.

Abstract


  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.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-6lo-paging-dispatch/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-6lo-paging-dispatch/ballot/


No IPR declarations have been submitted directly on this I-D.

(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 registries.


(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 event.

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


Personnel:

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

Document Shepherd: james woodyatt
Area Director: suresh.krishnan@ericsson.com


(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 http://www.ietf.org/tools/idnits/ 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?

Yes.


(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 procedure.

No.


(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 4944.


(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 allocations.


(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