RObust Header Compression (ROHC): A Profile for TCP/IP (ROHC-TCP)
draft-sandlund-rfc4996bis-02

[Ballot comment]
I think this should be addressed, but there is no appetite to do so:

  The issue below is the same as the one raised in the Gen-ART Review
  by Joel Halpern on 16-July-2012.

  Section 5.2.2.2 on negative acknowledgments includes the following:
  >
  > ... unless it has confidence that information sent after the packet
  > being acknowledged already provides a suitable response ...
  >
  This deals with a specific response to the NACK, it is unclear what
  constitutes confidence.  Other places in this document that refer to
  gaining confidence provide specific descriptions of how it is gained.
  The primary methods for gaining confidence are receiving acks or
  sufficient transmissions.  If all that is meant here is sufficient
  transmissions, please say so.

[Ballot comment]
As Sean says it would be useful to have the differences more visible at the front of the document. A forward reference in the Introduction would in my view be an acceptable way to achieve this.

[Ballot discuss]

  The issue below is the same as the one raised in the Gen-ART Review
  by Joel Halpern on 16-July-2012.

  Section 5.2.2.2 on negative acknowledgments includes the following:
  >
  > ... unless it has confidence that information sent after the packet
  > being acknowledged already provides a suitable response ...
  >
  This deals with a specific response to the NACK, it is unclear what
  constitutes confidence.  Other places in this document that refer to
  gaining confidence provide specific descriptions of how it is gained.
  The primary methods for gaining confidence are receiving acks or
  sufficient transmissions.  If all that is meant here is sufficient
  transmissions, please say so.

[Ballot comment]
I think it would be better if the changes were nearer the front of the draft.  I suggest moving s9 to s1.1 (again this is only a suggestion).

[Ballot comment]

- The new text in the intro, 2nd para, says something "must
be supported." Is that a 2119 MUST? If so, does it need to be
elsewhere as well if you're avoiding 2119 terms in the intro?
I didn't spot that when looking at the diff vs. 4996, so
where is the relevant 2119 language for that new(?) "must"?

- In the same intro text it might be better to s/may
not/cannot/ just to avoid 2119-like terms.

- In section 3, 2nd last para, you've taken out compression
of NULL-encrypted ESP headers (rfc 4303). Wouldn't it be nice
to call that out explicitly so that someone updating code
might more easily spot it without having to diff vs. RFC
4996? Similar comment on the list on p22 and p35. I realise
you point this out in 9.1, but it might be nice to also
note it in the places from which its been removed. (Note
that this is just a "nice-to-have" kind of comment, I've
no problem at all if you'd rather not change.)

IANA has reviewed draft-sandlund-rfc4996bis-02 and has the following comments:

IANA understands that upon approval of this document, there is
a single action which IANA must complete.

In the Profile Identifiers subregistry of the RObust Header Compression (ROHC)
Profile Identifiers registry located at:

http://www.iana.org/assignments/rohc-pro-ids/rohc-pro-ids.xml

the Profile Identifier 0x0006 currently has a reference of RFC 4996. This will
be changed to [ RFC-to-be ]. is updated to point to this document instead of
RFC4996. IANA understands that the profile numbers 0xnn06 have been reserved
for future updates of this profile. This is already present in the registry
and IANA understands that no further changes are necessary.

IANA understands that this single action is all that needs to be
completed to meet the IANA related requirements of 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.

The following Last Call announcement was sent out:

From: The IESG
To: IETF-Announce
Reply-To: ietf@ietf.org
Subject: Last Call:  (RObust Header Compression (ROHC): A Profile for TCP/IP (ROHC-TCP)) to Proposed Standard


The IESG has received a request from an individual submitter to consider
the following document:
- 'RObust Header Compression (ROHC): A Profile for TCP/IP (ROHC-TCP)'
  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 2012-06-29. 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 document specifies a ROHC (Robust Header Compression) profile
  for compression of TCP/IP packets.  The profile, called ROHC-TCP,
  provides efficient and robust compression of TCP headers, including
  frequently used TCP options such as SACK (Selective Acknowledgments)
  and Timestamps.

  ROHC-TCP works well when used over links with significant error rates
  and long round-trip times.  For many bandwidth-limited links where
  header compression is essential, such characteristics are common.

  This specification obsoletes [RFC4996].  It fixes a technical issue
  with the SACK compression and clarifies other compression methods
  used.



The file can be obtained via
http://datatracker.ietf.org/doc/draft-sandlund-rfc4996bis/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-sandlund-rfc4996bis/ballot/


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

1 - It seems that the IANA considerations should instead be asking
    IANA to update the registry entries pointing to 4996 to now point
    to the new RFC

2 - Since 4996, TCP-AO has been published on the Standards Track and
    should be considered (or at least mentioned) similarly to how the
    other TCP options are.  It may be difficult to effectively compress;
    it was not studied in the earlier field behavior work.

3 - There should be a mention that there are other (experimental) TCP
    options defined, and some in-use, which are not supported by this
    profile (e.g. MPTCP), though I don't think you should be required
    to actually address these effectively.

4 - ESP-NULL is still mentioned as supported in the 2nd to last
    paragraph of Section 3.2 even though it has been removed elsewhere
    in the document.

Write up for draft-sandlund-rfc4996bis:

(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

  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.

  This document specifies ROHC-TCP, a Robust Header Compression
  (ROHC) profile for TCP/IP packets. ROHC-TCP provides efficient
  compression of TCP headers including TCP options. It obsoletes the
  previous specification of RFC 4996 and corrects SACK compression
  method and clarifies some of the other compression methods.

Working Group Summary

  Was the document considered in any WG, and if so, why was
  it not adopted as a work item there? Was there controversy
  about particular points that caused the WG to not adopt the
  document?

  The correction was initiated by the authors when an interoperability
  issue was reported for the SACK compression. There is no controversy
  that caused this document to end up without a working group. The new
  document included only smaller changes to RFC 4996 and the most
  suitable candidate, the rohc working group, was concluded over two
  years ago. The draft has been posted on the rohc mailing list which
  is still in use.

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 existing implementations of RFC 4996 (ROHC-TCP). The
  ROHC-FN formal language have been reviewed by ROHC-FN author Robert
  Finking as well as implementers.

Personnel

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

  Carl Knutsson is the Document Shepherd and Wesley Eddy is the
  responsible AD.

(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.

There was a smaller correction in the IANA section as a result of the
review. I think the document is ready for publication. The review was
performed in 3 steps:
  1) All changes to RFC4996 reviewed.
  2) Review of included RFC Erratas for RFC4996 (and for sister draft
    RFC5225 ROHCv2)
  3) The document was reviewed as a whole.


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

No concerns.

(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.

No concerns.

(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 interested community 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.

No concerns.

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

No IPR disclosures have been filed for RFC 4996 or this document that I
know of.

(9) How solid is the consensus of the interested community behind this
document? Does it represent the strong concurrence of a few individuals,
with others being silent, or does the interested community as a whole
understand and agree with it?

No concerns.

(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.)

No concerns.

(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.

No concerns.

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

No concerns.

(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?

No concerns

(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 concerns.

(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 interested community considers it unnecessary.

It will obsolete and replace RFC 4996.

(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).

All IANA registries are already done in RFC 4996. The IANA need to
point all RFC 4996 references to this document.

(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.

No new registries.

(19) Describe reviews and automated checks performed by to validate
sections of the document written in a formal language, such as XML code,
BNF rules, MIB definitions, etc.

The robust header compression formal notation (ROHC-FN) specified in
RFC 4997 was is used in this document. A large part of this code have
been reused in from the previous RFC 4995 and the RFC 5225. RFC 5225
used the RFC 4996 code as a base and made small changes in the
code. Those changes were included into this document. Only one small
encoding method was written from scratch. The authors of ROHC-FN have
reviewed the new code as well as implementers of ROHC-TCP.