# Document Shepherd Write-Up for Group Documents
*This version is dated 4 July 2022.*
Thank you for your service as a document shepherd. Among the responsibilities is
answering the questions in this write-up to give helpful context to Last Call
and Internet Engineering Steering Group ([IESG][1]) reviewers, and your
diligence in completing it is appreciated. The full role of the shepherd is
further described in [RFC 4858][2]. You will need the cooperation of the authors
and editors to complete these checks.
Note that some numbered items contain multiple related questions; please be sure
to answer all of them.
## Document History
1. Does the working group (WG) consensus represent the strong concurrence of a
few individuals, with others being silent, or did it reach broad agreement?
There is strong consensus in the WG, except for one individual.
2. Was there controversy about particular points, or were there decisions where
the consensus was particularly rough?
The only area of controversy (argued by one individual) is related to
sending of ACKs in response to ACKs. This does not happen with TCP stacks
which are not supporting the extension defined in this document.
The problem described happens when the sender of an ACK receives an ACK for
its ACK, because it might trigger undesired reactions due to incorrectly
interpreting the received ACK as a duplicate ACK. In particular, this
misinterpretation could happen if the SACK extension is not used.
To mitigate this problem, the use of the SACK extension is recommended,
and if the SACK extension is supported, support for the DSACK extension
is required.
However, to trigger the sending of ACKs of ACKs requires the sender of
the initial ACKs to set the ECN code point to ECT. Doing so, is not
described in this document, but in another document
(draft-ietf-tcpm-generalized-ecn), which also requires the use of the SACK
extension.
In general, the view of the rest of the WG is that a TCP endpoint not being
able to deal with the ACKs of ACKs in an appropriate manner just should not
mark the pure ACKs it is sending with ECT.
3. Has anyone threatened an appeal or otherwise indicated extreme discontent? If
so, please summarize 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.)
One individual has raised the issue described above.
4. For protocol documents, are there existing implementations of the contents of
the document? Have a significant number of potential implementers indicated
plans to implement? Are any existing implementations reported somewhere,
either in the document itself (as [RFC 7942][3] recommends) or elsewhere
(where)?
* Apple has an implementation in its latest released version of their
operating systems. Disabled by default.
* There is an implementation for FreeBSD, which will be committed to the
source tree, as soon as the document is finished.
* There is also an implementation for Linux where people are working on getting
it into the main tree.
* Tooling support is also there. Wireshark support is there and also support
in packetdrill.
All this support was possible, since the TCP option kind numbers where early
assigned.
## Additional Reviews
5. Do the contents of this document closely interact with technologies in other
IETF working groups or external organizations, and would it therefore benefit
from their review? Have those reviews occurred? If yes, describe which
reviews took place.
The document deals with ECN markings, which are, for example, discussed in
TSVWG. It was made sure to involve people from TSVWG in the discussion and
review of this document.
6. Describe how the document meets any required formal expert review criteria,
such as the MIB Doctor, YANG Doctor, media type, and URI type reviews.
No part of the document needs such formal review.
7. If the document contains a YANG module, has the final version of the module
been checked with any of the [recommended validation tools][4] for syntax and
formatting validation? If there are any resulting errors or warnings, what is
the justification for not fixing them at this time? Does the YANG module
comply with the Network Management Datastore Architecture (NMDA) as specified
in [RFC 8342][5]?
The document does not contain a YANG module.
8. Describe reviews and automated checks performed to validate sections of the
final version of the document written in a formal language, such as XML code,
BNF rules, MIB definitions, CBOR's CDDL, etc.
The document does not contain such sections.
## Document Shepherd Checks
9. Based on the shepherd's review of the document, is it their opinion that this
document is needed, clearly written, complete, correctly designed, and ready
to be handed off to the responsible Area Director?
Yes to all questions above.
10. Several IETF Areas have assembled [lists of common issues that their
reviewers encounter][6]. For which areas have such issues been identified
and addressed? For which does this still need to happen in subsequent
reviews?
No issues have been identified.
11. What type of RFC publication is being requested on the IETF stream ([Best
Current Practice][12], [Proposed Standard, Internet Standard][13],
[Informational, Experimental or Historic][14])? Why is this the proper type
of RFC? Do all Datatracker state attributes correctly reflect this intent?
The intended status is Proposed Standard. It was extensively discussed in
the WG that this is the correct state. The alternative would have been
Experimental. But there is no need for an experiment.
12. Have reasonable efforts been made to remind all authors of the intellectual
property rights (IPR) disclosure obligations described in [BCP 79][7]? To
the best of your knowledge, have all required disclosures been filed? If
not, explain why. If yes, summarize any relevant discussion, including links
to publicly-available messages when applicable.
Yes, all authors where directly contaced and stated that to their knowledge
all IPRs have been disclosed.
There is one IPR declaration (https://datatracker.ietf.org/ipr/1881/) from
NetApp. Please note that one of the co-authors (Richard Scheffenegger from
NetApp) said, that the IPR was declared for an older version of the
document and the current documents is not affected by the IPR anymore.
13. Has each author, editor, and contributor shown their willingness to be
listed as such? If the total number of authors and editors on the front page
is greater than five, please provide a justification.
Yes.
14. Document any remaining I-D nits in this document. Simply running the [idnits
tool][8] is not enough; please review the ["Content Guidelines" on
authors.ietf.org][15]. (Also note that the current idnits tool generates
some incorrect warnings; a rewrite is underway.)
No.
15. Should any informative references be normative or vice-versa? See the [IESG
Statement on Normative and Informative References][16].
No.
16. List any normative references that are not freely available to anyone. Did
the community have sufficient access to review any such normative
references?
None.
17. Are there any normative downward references (see [RFC 3967][9] and [BCP
97][10]) that are not already listed in the [DOWNREF registry][17]? If so,
list them.
No.
18. Are there normative references to documents that are not ready to be
submitted to the IESG for publication or are otherwise in an unclear state?
If so, what is the plan for their completion?
No, all normative references are to already published RFCs.
19. Will publication of this document change the status of any existing RFCs? If
so, does the Datatracker metadata correctly reflect this and are those RFCs
listed on the title page, in the abstract, and discussed in the
introduction? If not, explain why and point to the part of the document
where the relationship of this document to these other RFCs is discussed.
This document updates RFC 3168, but both documents are PS. The relation to
RFC 3168 is listed on the title page and discussed on the abstract and in
the introduction.
However, this is NOT mentioned in the Datatracker metadata. To be honest,
I don't know where it should be in the Datatracker metadata.
20. 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 aspects of the document requiring IANA assignments are
associated with the appropriate reservations in IANA registries. Confirm
that any referenced IANA registries have been clearly identified. Confirm
that each newly created IANA registry specifies its initial contents,
allocations procedures, and a reasonable name (see [RFC 8126][11]).
The document defines one bit of the TCP flags (bit number 7) and
specifies two TCP options. The TCP option kinds have been early allocated
and they can already used in existing implementations.
The registries are clearly identified.
There are no new IANA registries.
21. List any new IANA registries that require Designated Expert Review for
future allocations. Are the instructions to the Designated Expert clear?
Please include suggestions of designated experts, if appropriate.
This document does not define any new IANA registries.
[1]: https://www.ietf.org/about/groups/iesg/
[2]: https://www.rfc-editor.org/rfc/rfc4858.html
[3]: https://www.rfc-editor.org/rfc/rfc7942.html
[4]: https://wiki.ietf.org/group/ops/yang-review-tools
[5]: https://www.rfc-editor.org/rfc/rfc8342.html
[6]: https://wiki.ietf.org/group/iesg/ExpertTopics
[7]: https://www.rfc-editor.org/info/bcp79
[8]: https://www.ietf.org/tools/idnits/
[9]: https://www.rfc-editor.org/rfc/rfc3967.html
[10]: https://www.rfc-editor.org/info/bcp97
[11]: https://www.rfc-editor.org/rfc/rfc8126.html
[12]: https://www.rfc-editor.org/rfc/rfc2026.html#section-5
[13]: https://www.rfc-editor.org/rfc/rfc2026.html#section-4.1
[14]: https://www.rfc-editor.org/rfc/rfc2026.html#section-4.2
[15]: https://authors.ietf.org/en/content-guidelines-overview
[16]: https://www.ietf.org/about/groups/iesg/statements/normative-informative-references/
[17]: https://datatracker.ietf.org/doc/downref/