Hares next steps:
# 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?
Strong concurrence. We had solid early reviews from RTG-DIR, SEC-DIR, OPS-DIR,
and individuals on the list. Any issues raised have been resolved by authors in
-01.
RTG-DIR reviewer: Andrew Alston - issues, that were resolved
https://datatracker.ietf.org/doc/review-ietf-idr-nhc-00-rtgdir-early-alston-2026-02-03/
email:
https://mailarchive.ietf.org/arch/msg/rtg-dir/Bc8IXgy8zhCMdkAPoK7t9n7Fclc/
In this review, Andrew states that:
"In section 2.5 of the draft, reference is made to anycast next-hops. My
concern is that this text probably needs to be expanded to cover cases where
the next-hop is something indirectly resolved."
John responded with:
"Thanks for raising this point and for your patience while I got around to
thinking and replying. The issue you’ve raised is that the draft assumes the
forwarding path has something to do with the next hop: "Since the NHC is
intended chiefly for conveying information about forwarding plane features, it
needs to be regenerated whenever the BGP route's next hop is changed.” But,
sadly, there are various ways in BGP to have the forwarding path NOT follow the
next hop, including the example you gave, the Tunnel Encapsulation Attribute,
and almost certainly others as well." Therefore, John wrote a paragraph about
the issues with Tunnel Encapsulation Attribute. John resolved this to Andrews
Alston's satisfaction.
The shepherd thinks John's resolution is a reasonable one.
SEC-Dir reviewer: Wes Hardaker
https://datatracker.ietf.org/doc/review-ietf-idr-nhc-00-secdir-early-hardaker-2026-01-30/
Email: https://mailarchive.ietf.org/arch/msg/secdir/nLqb8oaRLpcIpUgVomebppfBGEs/
Wes raised the point:
"could colluding entities on either side of a NHC supporting device collude to
get it to reveal information about it's policies and habits (more than it could
without NHC)?"
OPS-DIR Reviewer: Giuseppe Fioccola - status ready with NITs and fix from John
https://mailarchive.ietf.org/arch/msg/idr/-t4E61Dj23EymsXdsnHp7fxdzsY/
2. Was there controversy about particular points, or were there decisions where
the consensus was particularly rough?
The conversation on the draft had good review and good consensus.
The summary of the discussion includes:
1) Early Reviews note above (OPS-DIR, RTG-DIR, SEC-DIR)
1. Tom Petch mentioning a broken reference to
draft-wang-idr-next-next-hop-nodes-01 and textual changes 2. OPS-DIR (review
mentioned compliance to RFC5706bis (draft-ietf-opsawg-rfc5706bis-02) John
Scudder notes the temporal order of the creation of these drafts meant this
draft was in final form waiting for WG LC and implementations prior to this
draft.
Call referenced:
WG LC initial call:
https://mailarchive.ietf.org/arch/msg/idr/DnsWUvtDxGGAMPFs0pwtcbsQV9M/
WG LC Extended:
https://mailarchive.ietf.org/arch/msg/idr/kLc8fb1-fow78-pvK3lSSLTeX-M/
Post WG LC Shepherd report:
https://mailarchive.ietf.org/arch/msg/idr/QLIaLuPwKaoRGXxU-54S8_i0fIM/
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.
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)?
Existing implementations: see
https://wiki.ietf.org/group/idr/implementations/draft-ietf-idr-nhc The amount
of detail on this implementation page is impressive.
## 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.
RTG-DIR, OPS-DIR, SEC-DIR. See comments above.
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 formal reviews.
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]?
No formal reviews.
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.
No formal reviews.
## 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?
The early review took into account issues related to routing, security, and
operations.
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?
Proposed standard. The BGP Next Hop Dependent Characteristics attribute
(NHC attribute, or just NHC) is an optional, transitive BGP path attribute with
type code 39. It augments [RFC4271], but does not modify it.
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.
IPR Statements from 7 authors:
Bruno Decraene
https://mailarchive.ietf.org/arch/msg/idr/DtOZjeUsgFef8Zbwco--o-Xqp9M/
Kireeti Kompella
Serge Krier
https://mailarchive.ietf.org/arch/msg/idr/AvdQg_0ZhC1pFVzAjsdj_q5o4UI/
Satya Mohanty
https://mailarchive.ietf.org/arch/msg/idr/7Dpg77ttyno4_DCX929R-fpYXCQ/
John Scudder
https://mailarchive.ietf.org/arch/msg/idr/4foGpV00mnqO3F_GhEdIbKWFChU/
Kevin Wang
https://mailarchive.ietf.org/arch/msg/idr/WQGFDysVq4zgrMM636BQIOwb6g4/
Bin Wen
https://mailarchive.ietf.org/arch/msg/idr/sANtu7cipsNDVxbLzoQNfRWKaGI/
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. The agreement to allow 7 authors was because the
draft-ietf-idr-entropy-label was the merge of two drafts
(draft-scudder-idr-entropy-label, draft-ietf-idr-next-hop-capability). We want
to encourage these type of merges - so this shepherd has forwarded this to the
IESG.
The merged draft of draft-ietf-idr-entropy-label was split to into
draft-ietf-idr-nhc-01 and draft-ietf-idr-nlc. Only draft-ietf-idr-nhc-00
had two implementations and a decision was made to progress
draft-ietf-idr-nhc-01. See
https://datatracker.ietf.org/doc/draft-ietf-idr-entropy-label/
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.)
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?
All reference are IETF RFCs or drafts.
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
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.
No.
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]).
I reviewed the section, and I asked IANA to do an early review.
IANA is requested to create a new registry called "BGP Next Hop
Dependent Characteristic Codes" within the Border Gateway Protocol
(BGP) Parameters group. The registry's allocation policy is First
Come, First Served, except where designated otherwise in Table 2
in the document.
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.
Only a FCFS registry.
[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/