UDP Options (draft-ietf-tsvwg-udp-options)
# Document Shepherd Write-Up for Group Documents
*This version is dated 4 July 2022.*
## 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?
The TSVWG working group has worked on this document since adopting this in
2017. It has been discussed extensively and has been stable in recent
revisions. The document introduces an options format for UDP, for which ether
was support from the WG. From the start it was clear that use of this format is
optional, it was understood that many protocols layered over UDP already
support options (SCTP, RTP, QUIC, DCCP, etc) and could be more appropriately
extended using their own options space. A key addition offered by the set of
options is support for methods to offer fragmentation at the UDP layer.
The first complete revision of the specification was reviewed by the WG. There
was an invited protocol technical review from Colin Perkins (on
draft-ietf-tsvwg-udp-options-19) in 2023 and it was updated. An issue tracker
was used and all open issues from invited technical reviews and the WGLCs have
been resolved. Each time the document was discussed and reviewed.
The WG decided to separate the procedures for using DPLPMTUD with the RES/REQ
option into a separate draft. The WG also decided the procedures for using the
AUTH and Encryption options ought to be in separate I-Ds (currently an
individual I-D exist for AUTH). The base document describes a process where
receivers are allowed to ignore the AUTH option and accept the packet without
verifying the authentication, or when there is no policy to do this.
A registry is described. If needed, the specification can be further extended.
The document retains the support of the TSVWG working group, and there is
consensus (rough) to publish this version.
2. Was there controversy about particular points, or were there decisions where
the consensus was particularly rough?
2.1 Timestamp: There were some additional requests from a small number of
people for changes to the timestamp format. The design was not changed, and
this was confirmed on the list.
2.2 Network devices on the network path: UDP options can by default be read by
network devices on the network path, in the same way that devices can read IP
extensions/options and are often able to read tunnel headers. An explicit
consensus call in May 2024, prior to WGLC confirmed that: 1. Routers ought to
forward packets with UDP Options without modification, i.e.: "UDP Options MUST
NOT be modified in transit". 2. the WG was content that “"UDP options are
intended for use only by the transport endpoints. They are no more (or less)
appropriate to be modified in-transit than any other portion of the transport
datagram." 3. UDP Options does not by itself provide any mechanism for a device
to authenticate the format or contents of the options data, or to detect if the
surplus area has been removed from a packet.
2.3 Authentication and Encryption: UDP options defines the option format and
rules for parsing of the UDP headers, but not the procedures for using the
option information. The procedures in any additional I-Ds might describe how to
establish a security context and procedures for how this is used to validate
and forward authenticated data. This design in the latest rev was confirmed on
the list (see 3).
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.)
No, but when this design decision was confirmed on list, two people disagreed
with this design. It was asserted that the AUTH option is not sufficiently
specified or implemented to make a sufficient evaluation of its security
characteristics, and that they think that inability to successfully process an
AUTH option within UDP options needs to result in discard of a datagram. The
Comments were received that helped to refine the proposed text. The editors
proposed to retain the process for parsing the option, because this could then
describe how the option related to the processing of other options, e.g. for
fragmentation, but the text was amended to identify how the option ought to be
configured when used.
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)?
Results were presented to the WG for tests using the option format across a
range of Internet paths to explore traversal (whether an option is passed or
modified by devices on path); and the method has been updated to reflect this
experience. Significant inputs were provided on approaches to implementation, a
pilot integration into a fork of BSD provided input; as did consideration of
the requirements for offload; and exploration of the complexity of the various
proposed fragmentation methods. It is therefore expected that the protocol is
implementable. The shepherd is not aware of an implementation or the proposed
transport API that supports the final specification.
## 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.
No.
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.
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]?
N/A.
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.
None.
## 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.
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?
N/A.
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?
This is a Standards Track update to an existing Standards Track specification.
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. There is one related IPR disclosure: Cisco's Statement about IPR related
to draft-touch-tsvwg-udp-options. The WG was aware of this disclosure.
Both Editors have confirmed their obligations described in BCP 79.
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.)
This draft intentionally includes an obsolete informational reference is
intentional for: RFC 793 (Obsoleted by RFC 9293).
15. Should any informative references be normative or vice-versa? See the [IESG
Statement on Normative and Informative References][16].
Checked.
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?
The WG decided to separate the procedures for using DPLPMTUD with the RES/REQ
option into a separate draft (draft-ietf-tsvwg-udp-options-dplpmtud). This is
requested to be co-published with this I-D. A normative reference is included.
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 will update a core IETF Spec, RFC 768.
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]).
This was revised. A new registry is defined.
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.
Upon publication, IANA is hereby requested to create a new registry
group for UDP Options. The two suggested experts are:
Joe Touch
Mike Heard.
[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/