Optimizing BFD Authentication
draft-ietf-bfd-optimizing-authentication-21

=======================================================================================
Update December 31st 2024 on draft-ietf-bfd-optimizing-authentication-21

## 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 consensus of a few individuals.
The initial revision of this document is from 2015. Since then there have been multiple
discussions on the BFD alias and in in-person WG meetings. The "recent" changes to the
document to use ISAAC are the ones on which the WG has been mostly silent.

There has been opposition by one person (see 2 below).

2. Was there controversy about particular points, or were there decisions where
  the consensus was particularly rough?

There has been controversy because of the IPR Disclosure.
https://mailarchive.ietf.org/arch/msg/rtg-bfd/u8rvWwvDWRKI3jseGHecAB9WtDo/

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)?

No implementations and no known plans to implement.

## 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 and 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.

The document has undergone a YANG Doctor 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?

Yes.

  If there are any resulting errors or warnings, what is
  the justification for not fixing them at this time?

No errors.

  Does the YANG module
  comply with the Network Management Datastore Architecture (NMDA) as specified
  in [RFC 8342][5]?

Yes.

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.

YANG has been validated.

## 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?

The document is clearly written and nearly ready.
There are some comments to be addressed before the document is handed off to the responsible AD:
https://mailarchive.ietf.org/arch/msg/rtg-bfd/ca_gCMOCyXGNhhTBAvg5lGLXJK8/

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?

There has been a secdir review and comments have been addressed:
https://mailarchive.ietf.org/arch/msg/rtg-bfd/303D-DZ2DVFr9frgy75b6yyiILk/

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])?

Experimental as indicated on title page.

    Why is this the proper type
    of RFC?
Main reasons:
- No known implementations
- Not a lot of reviews on the latest revisions of the document

    Do all Datatracker state attributes correctly reflect this intent?
Yes.

12. Have reasonable efforts been made to remind all authors of the intellectual
    property rights (IPR) disclosure obligations described in [BCP 79][7]?
Yes.

    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.
Waiting for response from 1 co-author.


13. Has each author, editor, and contributor shown their willingness to be
    listed as such?
Yes.

    If the total number of authors and editors on the front page
    is greater than five, please provide a justification.
N/A.

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.)
  Miscellaneous warnings:
  ----------------------------------------------------------------------------

  == The document seems to lack the recommended RFC 2119 boilerplate, even if
    it appears to use RFC 2119 keywords -- however, there's a paragraph with
    a matching beginning. Boilerplate error?

    (The document does seem to have the reference to RFC 2119 which the
    ID-Checklist requires).
  -- The document date (21 October 2024) is 71 days in the past.  Is this
    intentional?

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?
N/A

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. Note that this document should be in the same bundle as draft-ietf-bfd-secure-sequence-numbers (which is updated in "locked-step" with this document).

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. This is an experimental document.

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]).
Section 6 matches the rest of the document and confirming the above where applicable.

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.
Assignment from the “BFD Authentication Types” registry requires Expert review. Checked https://www.iana.org/assignments/bfd-parameters/bfd-parameters.xhtml
There is also an updated IANA YANG module in the appendix.

[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/

=======================================================================================

Update Nov 23rd 2020

All comments have been addressed.

Update July 23rd 2020

Revised comments on draft-ietf-bfd-optimizing-authentication-10

General: both "BFD control packet" and "BFD packet" are used. I think we should stick to "BFD control packet".
General: s/BFD Control packet/BFD control packet/

Introduction, next-to last paragraph. Instead of "The interval of this non-state change frame can be...", I'd suggest "The interval of these BFD packets can be..." or "The interval of the BFD packets without a significant change can be...". Anyway remove "frame" as previously discussed and avoid use of "non-state change" now that you've defined what a significant change is.

Section 1.2. The new table could be incorrectly interpreted as having 1 entry. Suggest changing this to bullet form would make it clearer.

Section 1.2 introduces the term "configured interval" but section 2 uses the term "configured period". Also for the description, what about "interval at which BFD control packets are authenticated in the UP state".
Also wondering if instead we should have a new bfd.AuthUpStateInterval state variable (see 6.8.1 of RFC5880) since having this value may not always be configured (implementation specific)?

Section 2. Replace  "frame" by "packet" or "BFD control packet"  as appropriate.

Section 2. Thanks for modifying the table as per our discussions. Regarding adding AdminDown to the table, I believe I misled you. Our discussion was based on "what happens if we're UP and receive a packet which says AdminDown"? As per 6.2 of RFC5880, the receiver would go to DOWN state. However the rows/columns in the table are for the local state (new and old), and not for state in received packet. Since we can't go to AdminDown state or leave AdmnDown state based on a packet received, AdminDown state should be removed from this table . I think it'd be good to add a reference to the BFD FSM (6.8.2 of RFC5880) in the paragraph before the table.

Section 2. For configured period (or whatever we decide to call it) add a reference to section 1.2.

Section 4. s/to to/to/

=============================================================

(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?
Standards Track as indicated on title page.

(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:
This document describes an optimization to BFD Authentication as described in Section 6.7 of RFC5880. To remove the computational load on end-systems running BFD, it removes the requirement to authenticate all BFD control packets while providing a mechanism to keep the BFD sessions secure.

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.

Working Group Summary:
Initial revision of the document is from  February 2015. Since then there have been many discussions on the mailing list and in-person at BFD WG meetings. The document has improved significantly based on the various suggestions. There is consistency on the technical content.

One action which has been postponed is updating the BFD YANG model to enable this functionality (requires a -bis of the BFD YANG document due to the new auth-type) 

There has been controversy because of the IPR Disclosure, see below.

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?

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, YANG 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?

The document is well-written, concise and technically accurate, but requires some editorial changes before being forwarded to the IESG.


Personnel:

Who is the Document Shepherd?
Reshad Rahman, BFD co-chair.

Who is the Responsible Area Director?
Martin Vigoureux 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.
The shepherd has gone through the document, email archive and meeting minutes. Comments have been addressed.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews that have been performed?
None.

(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.
This document was discussed with security experts. This led to draft-ietf-bfd-secure-numbers.


(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.
None

(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?
Yes

(8) Has an IPR disclosure been filed that references this document? If so, summarize any WG discussion and conclusion regarding the IPR disclosures.
https://datatracker.ietf.org/ipr/3328/
There has been controversy on the IPR disclosure on this document for 2 main reasons:
i) IPR disclosure was late (Nov 2018)
ii) The terms of the IPR
The IPR disclosure and terms were discussed at length on the mailing list and in the WG meetings:
https://datatracker.ietf.org/meeting/104/materials/minutes-104-bfd-00.pdf
https://datatracker.ietf.org/meeting/105/materials/minutes-105-bfd-02.pdf



(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?
Solid consensus on the technical aspects.
There is known opposition from 1 person (because of the IPR Disclosure).
https://mailarchive.ietf.org/arch/msg/rtg-bfd/u8rvWwvDWRKI3jseGHecAB9WtDo/


(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.)
None

(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.
3 warnings:
  == The copyright year in the IETF Trust and authors Copyright Line does not
    match the current year

  == The document seems to lack the recommended RFC 2119 boilerplate, even if
    it appears to use RFC 2119 keywords -- however, there's a paragraph with
    a matching beginning. Boilerplate error?

  == Outdated reference: A later version (-05) exists of
    draft-ietf-bfd-secure-sequence-numbers-04

Comment about document data being 186 days in the past.

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

(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?
None

(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.
None

(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.
No

(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 8126).
Assignment from the “BFD Authentication Types” registry requires Expert review. Checked https://www.iana.org/assignments/bfd-parameters/bfd-parameters.xhtml

(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.
None

(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, YANG modules, etc.
N/A

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) 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 RFC8342?
N/A


COMMENTS

General:
• Updates RFC5880 missing from title page
• Replace BFD frames by BFD packets or BFD control packets. Don’t use frames since RFC5880 uses packets.
• Use of term Null-authentication TLV. RFC5880 uses authentication section, doesn’t mention auth TLV.

Abstract:
Mention that this document updates RFC5880.

Requirements Language
Please put this is a separate (sub)section later, e.g. after introduction.

Introduction
First paragraph: s/is computationally intensive process/is a computationally intensive process/
Split first sentence into 2, e.g.
  Authenticating every BFD [RFC5880] packet with a Simple Password, or
  with a MD5 Message-Digest Algorithm [RFC1321], or Secure Hash
  Algorithm (SHA-1) algorithms is a computationally intensive process.
  This makes it difficult, if not impossible, to authenticate every packet,
  particularly at faster rates.

2nd paragraph: “… only BFD frames that signal a state change in BFD be authenticated.” State change is not 100% correct since P/F/D bit changes aren’t state changes (as mentioned in more detail below in section 2 comments). What about this instead: “State change, a demand mode change (to D bit) or a poll sequence change (P or F bit change) in a BFD packet are categorized as a significant BFD change. This document proposes that all BFD control packets which signal a significant BFD change MUST be authenticated if the session’s bfd.AuthType is non-zero. Other BFD control packets MAY be transmitted and received without the A bit set.” If you do use “significant BFD change”, add it to terminology section.
s/non-state change frame/BFD control packets without state or D/F/P bit change/, e.g.
“To detect a Man In the Middle (MITM) attack, it is also proposed that BFD control packets without a significant change be authenticated occasionally.  The interval of these control packets…”

Section 2
POLL and DEMAND are NOT strictly states. POLL refers to “Poll sequence” as specified in section 6.5 of RFC5880. DEMAND refers to “Demand mode” as specified in section 6.6 of RFC5880. In the table, the POLL entry refers to polling sequence enabled and in any BFD state. Likewise, the DEMAND entry refers to Demand mode. This means that a session in UP state, in demand mode and polling sequence enabled will match 3 entries in that table. It’s a bit confusing. Here’s what I suggest instead:
1. Take POLL out of the table. Add a paragraph mentioning that if P or F bit changes value, the packet MUST be authenticated
2. Take DEMAND out of the table. Add a paragraph mentioning that if D bit changes value, the packet MUST be authenticated

Another comment on the table. The text says it should be read as state change from column to row. Column INIT to row UP is n/a whereas column UP to row INIT is Auth. INIT to UP is a valid transition, UP to INIT is not (has to go through DOWN first). So I think those entries should be reversed in the table.

Last paragraph: CC frames is not defined in BFD, use “control packets” instead?

Section 3
Sequence number mentions “as defined in [RFC5880]”. Suggest mentioning bfd.XmitAuthSeq

Security Considerations.
I believe this needs to be beefed up:
1) Use of sequence number for non-authenticated frames. Secure sequence numbers even better.
2) Mention (again) that non-authenticated BFD packets which have a significant change (state, D/F/P) are dropped. So if someone injects a non-authenticated packet with Down state to take down the session, that won’t work.

Section 6.2
RFC5880 should be a normative reference.

=======================================================================================
Update December 31st 2024 on draft-ietf-bfd-optimizing-authentication-21

## 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 consensus of a few individuals.
The initial revision of this document is from 2015. Since then there have been multiple
discussions on the BFD alias and in in-person WG meetings. The "recent" changes to the
document to use ISAAC are the ones on which the WG has been mostly silent.

There has been opposition by one person (see 2 below).

2. Was there controversy about particular points, or were there decisions where
  the consensus was particularly rough?

There has been controversy because of the IPR Disclosure.
https://mailarchive.ietf.org/arch/msg/rtg-bfd/u8rvWwvDWRKI3jseGHecAB9WtDo/

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)?

No implementations and no known plans to implement.

## 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 and 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.

The document has undergone a YANG Doctor 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?

Yes.

  If there are any resulting errors or warnings, what is
  the justification for not fixing them at this time?

No errors.

  Does the YANG module
  comply with the Network Management Datastore Architecture (NMDA) as specified
  in [RFC 8342][5]?

Yes.

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.

YANG has been validated.

## 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?

The document is clearly written and nearly ready.
There are some comments to be addressed before the document is handed off to the responsible AD:
https://mailarchive.ietf.org/arch/msg/rtg-bfd/ca_gCMOCyXGNhhTBAvg5lGLXJK8/

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?

There has been a secdir review and comments have been addressed:
https://mailarchive.ietf.org/arch/msg/rtg-bfd/303D-DZ2DVFr9frgy75b6yyiILk/

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])?

Experimental as indicated on title page.

    Why is this the proper type
    of RFC?
Main reasons:
- No known implementations
- Not a lot of reviews on the latest revisions of the document

    Do all Datatracker state attributes correctly reflect this intent?
Yes.

12. Have reasonable efforts been made to remind all authors of the intellectual
    property rights (IPR) disclosure obligations described in [BCP 79][7]?
Yes.

    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.
Waiting for response from 1 co-author.


13. Has each author, editor, and contributor shown their willingness to be
    listed as such?
Yes.

    If the total number of authors and editors on the front page
    is greater than five, please provide a justification.
N/A.

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.)
  Miscellaneous warnings:
  ----------------------------------------------------------------------------

  == The document seems to lack the recommended RFC 2119 boilerplate, even if
    it appears to use RFC 2119 keywords -- however, there's a paragraph with
    a matching beginning. Boilerplate error?

    (The document does seem to have the reference to RFC 2119 which the
    ID-Checklist requires).
  -- The document date (21 October 2024) is 71 days in the past.  Is this
    intentional?

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?
N/A

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?
This document should be in the same bundle as draft-ietf-bfd-secure-sequence-numbers

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. This is an experimental document.

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]).
Section 6 matches the rest of the document and confirming the above where applicable.

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.
Assignment from the “BFD Authentication Types” registry requires Expert review. Checked https://www.iana.org/assignments/bfd-parameters/bfd-parameters.xhtml
There is also an updated IANA YANG module in the appendix.

[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/

=======================================================================================

Update Nov 23rd 2020

All comments have been addressed.

Update July 23rd 2020

Revised comments on draft-ietf-bfd-optimizing-authentication-10

General: both "BFD control packet" and "BFD packet" are used. I think we should stick to "BFD control packet".
General: s/BFD Control packet/BFD control packet/

Introduction, next-to last paragraph. Instead of "The interval of this non-state change frame can be...", I'd suggest "The interval of these BFD packets can be..." or "The interval of the BFD packets without a significant change can be...". Anyway remove "frame" as previously discussed and avoid use of "non-state change" now that you've defined what a significant change is.

Section 1.2. The new table could be incorrectly interpreted as having 1 entry. Suggest changing this to bullet form would make it clearer.

Section 1.2 introduces the term "configured interval" but section 2 uses the term "configured period". Also for the description, what about "interval at which BFD control packets are authenticated in the UP state".
Also wondering if instead we should have a new bfd.AuthUpStateInterval state variable (see 6.8.1 of RFC5880) since having this value may not always be configured (implementation specific)?

Section 2. Replace  "frame" by "packet" or "BFD control packet"  as appropriate.

Section 2. Thanks for modifying the table as per our discussions. Regarding adding AdminDown to the table, I believe I misled you. Our discussion was based on "what happens if we're UP and receive a packet which says AdminDown"? As per 6.2 of RFC5880, the receiver would go to DOWN state. However the rows/columns in the table are for the local state (new and old), and not for state in received packet. Since we can't go to AdminDown state or leave AdmnDown state based on a packet received, AdminDown state should be removed from this table . I think it'd be good to add a reference to the BFD FSM (6.8.2 of RFC5880) in the paragraph before the table.

Section 2. For configured period (or whatever we decide to call it) add a reference to section 1.2.

Section 4. s/to to/to/

=============================================================

(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?
Standards Track as indicated on title page.

(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:
This document describes an optimization to BFD Authentication as described in Section 6.7 of RFC5880. To remove the computational load on end-systems running BFD, it removes the requirement to authenticate all BFD control packets while providing a mechanism to keep the BFD sessions secure.

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.

Working Group Summary:
Initial revision of the document is from  February 2015. Since then there have been many discussions on the mailing list and in-person at BFD WG meetings. The document has improved significantly based on the various suggestions. There is consistency on the technical content.

One action which has been postponed is updating the BFD YANG model to enable this functionality (requires a -bis of the BFD YANG document due to the new auth-type) 

There has been controversy because of the IPR Disclosure, see below.

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?

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, YANG 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?

The document is well-written, concise and technically accurate, but requires some editorial changes before being forwarded to the IESG.


Personnel:

Who is the Document Shepherd?
Reshad Rahman, BFD co-chair.

Who is the Responsible Area Director?
Martin Vigoureux 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.
The shepherd has gone through the document, email archive and meeting minutes. Comments have been addressed.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews that have been performed?
None.

(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.
This document was discussed with security experts. This led to draft-ietf-bfd-secure-numbers.


(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.
None

(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?
Yes

(8) Has an IPR disclosure been filed that references this document? If so, summarize any WG discussion and conclusion regarding the IPR disclosures.
https://datatracker.ietf.org/ipr/3328/
There has been controversy on the IPR disclosure on this document for 2 main reasons:
i) IPR disclosure was late (Nov 2018)
ii) The terms of the IPR
The IPR disclosure and terms were discussed at length on the mailing list and in the WG meetings:
https://datatracker.ietf.org/meeting/104/materials/minutes-104-bfd-00.pdf
https://datatracker.ietf.org/meeting/105/materials/minutes-105-bfd-02.pdf



(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?
Solid consensus on the technical aspects.
There is known opposition from 1 person (because of the IPR Disclosure).
https://mailarchive.ietf.org/arch/msg/rtg-bfd/u8rvWwvDWRKI3jseGHecAB9WtDo/


(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.)
None

(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.
3 warnings:
  == The copyright year in the IETF Trust and authors Copyright Line does not
    match the current year

  == The document seems to lack the recommended RFC 2119 boilerplate, even if
    it appears to use RFC 2119 keywords -- however, there's a paragraph with
    a matching beginning. Boilerplate error?

  == Outdated reference: A later version (-05) exists of
    draft-ietf-bfd-secure-sequence-numbers-04

Comment about document data being 186 days in the past.

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

(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?
None

(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.
None

(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.
No

(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 8126).
Assignment from the “BFD Authentication Types” registry requires Expert review. Checked https://www.iana.org/assignments/bfd-parameters/bfd-parameters.xhtml

(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.
None

(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, YANG modules, etc.
N/A

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) 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 RFC8342?
N/A


COMMENTS

General:
• Updates RFC5880 missing from title page
• Replace BFD frames by BFD packets or BFD control packets. Don’t use frames since RFC5880 uses packets.
• Use of term Null-authentication TLV. RFC5880 uses authentication section, doesn’t mention auth TLV.

Abstract:
Mention that this document updates RFC5880.

Requirements Language
Please put this is a separate (sub)section later, e.g. after introduction.

Introduction
First paragraph: s/is computationally intensive process/is a computationally intensive process/
Split first sentence into 2, e.g.
  Authenticating every BFD [RFC5880] packet with a Simple Password, or
  with a MD5 Message-Digest Algorithm [RFC1321], or Secure Hash
  Algorithm (SHA-1) algorithms is a computationally intensive process.
  This makes it difficult, if not impossible, to authenticate every packet,
  particularly at faster rates.

2nd paragraph: “… only BFD frames that signal a state change in BFD be authenticated.” State change is not 100% correct since P/F/D bit changes aren’t state changes (as mentioned in more detail below in section 2 comments). What about this instead: “State change, a demand mode change (to D bit) or a poll sequence change (P or F bit change) in a BFD packet are categorized as a significant BFD change. This document proposes that all BFD control packets which signal a significant BFD change MUST be authenticated if the session’s bfd.AuthType is non-zero. Other BFD control packets MAY be transmitted and received without the A bit set.” If you do use “significant BFD change”, add it to terminology section.
s/non-state change frame/BFD control packets without state or D/F/P bit change/, e.g.
“To detect a Man In the Middle (MITM) attack, it is also proposed that BFD control packets without a significant change be authenticated occasionally.  The interval of these control packets…”

Section 2
POLL and DEMAND are NOT strictly states. POLL refers to “Poll sequence” as specified in section 6.5 of RFC5880. DEMAND refers to “Demand mode” as specified in section 6.6 of RFC5880. In the table, the POLL entry refers to polling sequence enabled and in any BFD state. Likewise, the DEMAND entry refers to Demand mode. This means that a session in UP state, in demand mode and polling sequence enabled will match 3 entries in that table. It’s a bit confusing. Here’s what I suggest instead:
1. Take POLL out of the table. Add a paragraph mentioning that if P or F bit changes value, the packet MUST be authenticated
2. Take DEMAND out of the table. Add a paragraph mentioning that if D bit changes value, the packet MUST be authenticated

Another comment on the table. The text says it should be read as state change from column to row. Column INIT to row UP is n/a whereas column UP to row INIT is Auth. INIT to UP is a valid transition, UP to INIT is not (has to go through DOWN first). So I think those entries should be reversed in the table.

Last paragraph: CC frames is not defined in BFD, use “control packets” instead?

Section 3
Sequence number mentions “as defined in [RFC5880]”. Suggest mentioning bfd.XmitAuthSeq

Security Considerations.
I believe this needs to be beefed up:
1) Use of sequence number for non-authenticated frames. Secure sequence numbers even better.
2) Mention (again) that non-authenticated BFD packets which have a significant change (state, D/F/P) are dropped. So if someone injects a non-authenticated packet with Down state to take down the session, that won’t work.

Section 6.2
RFC5880 should be a normative reference.

=======================================================================================
Update December 31st 2024 on draft-ietf-bfd-optimizing-authentication-21

## 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 consensus of a few individuals.
The initial revision of this document is from 2015. Since then there have been multiple
discussions on the BFD alias and in in-person WG meetings. The "recent" changes to the
document to use ISAAC are the ones on which the WG has been mostly silent.

There has been opposition by one person (see 2 below).

2. Was there controversy about particular points, or were there decisions where
  the consensus was particularly rough?

There has been controversy because of the IPR Disclosure.
https://mailarchive.ietf.org/arch/msg/rtg-bfd/u8rvWwvDWRKI3jseGHecAB9WtDo/

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)?

No implementations and no known plans to implement.

## 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 and 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.

The document has undergone a YANG Doctor 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?

Yes.

  If there are any resulting errors or warnings, what is
  the justification for not fixing them at this time?

No errors.

  Does the YANG module
  comply with the Network Management Datastore Architecture (NMDA) as specified
  in [RFC 8342][5]?

Yes.

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.

YANG has been validated.

## 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?

The document is clearly written and nearly ready.
There are some comments to be addressed before the document is handed off to the responsible AD.

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?

There has been a secdir review and comments have been addressed:
https://mailarchive.ietf.org/arch/msg/rtg-bfd/303D-DZ2DVFr9frgy75b6yyiILk/

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])?

Experimental as indicated on title page.

    Why is this the proper type
    of RFC?
Main reasons:
- No known implementations
- Not a lot of reviews on the latest revisions of the document

    Do all Datatracker state attributes correctly reflect this intent?
Yes.

12. Have reasonable efforts been made to remind all authors of the intellectual
    property rights (IPR) disclosure obligations described in [BCP 79][7]?
Yes.

    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.
Waiting for response from 1 co-author.


13. Has each author, editor, and contributor shown their willingness to be
    listed as such?
Yes.

    If the total number of authors and editors on the front page
    is greater than five, please provide a justification.
N/A.

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.)
  Miscellaneous warnings:
  ----------------------------------------------------------------------------

  == The document seems to lack the recommended RFC 2119 boilerplate, even if
    it appears to use RFC 2119 keywords -- however, there's a paragraph with
    a matching beginning. Boilerplate error?

    (The document does seem to have the reference to RFC 2119 which the
    ID-Checklist requires).
  -- The document date (21 October 2024) is 71 days in the past.  Is this
    intentional?

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?
N/A

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?
This document should be in the same bundle as draft-ietf-bfd-secure-sequence-numbers

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. This is an experimental document.

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]).
Section 6 matches the rest of the document and confirming the above where applicable.

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.
Assignment from the “BFD Authentication Types” registry requires Expert review. Checked https://www.iana.org/assignments/bfd-parameters/bfd-parameters.xhtml
There is also an updated IANA YANG module in the appendix.

[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/

=======================================================================================

Update Nov 23rd 2020

All comments have been addressed.

Update July 23rd 2020

Revised comments on draft-ietf-bfd-optimizing-authentication-10

General: both "BFD control packet" and "BFD packet" are used. I think we should stick to "BFD control packet".
General: s/BFD Control packet/BFD control packet/

Introduction, next-to last paragraph. Instead of "The interval of this non-state change frame can be...", I'd suggest "The interval of these BFD packets can be..." or "The interval of the BFD packets without a significant change can be...". Anyway remove "frame" as previously discussed and avoid use of "non-state change" now that you've defined what a significant change is.

Section 1.2. The new table could be incorrectly interpreted as having 1 entry. Suggest changing this to bullet form would make it clearer.

Section 1.2 introduces the term "configured interval" but section 2 uses the term "configured period". Also for the description, what about "interval at which BFD control packets are authenticated in the UP state".
Also wondering if instead we should have a new bfd.AuthUpStateInterval state variable (see 6.8.1 of RFC5880) since having this value may not always be configured (implementation specific)?

Section 2. Replace  "frame" by "packet" or "BFD control packet"  as appropriate.

Section 2. Thanks for modifying the table as per our discussions. Regarding adding AdminDown to the table, I believe I misled you. Our discussion was based on "what happens if we're UP and receive a packet which says AdminDown"? As per 6.2 of RFC5880, the receiver would go to DOWN state. However the rows/columns in the table are for the local state (new and old), and not for state in received packet. Since we can't go to AdminDown state or leave AdmnDown state based on a packet received, AdminDown state should be removed from this table . I think it'd be good to add a reference to the BFD FSM (6.8.2 of RFC5880) in the paragraph before the table.

Section 2. For configured period (or whatever we decide to call it) add a reference to section 1.2.

Section 4. s/to to/to/

=============================================================

(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?
Standards Track as indicated on title page.

(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:
This document describes an optimization to BFD Authentication as described in Section 6.7 of RFC5880. To remove the computational load on end-systems running BFD, it removes the requirement to authenticate all BFD control packets while providing a mechanism to keep the BFD sessions secure.

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.

Working Group Summary:
Initial revision of the document is from  February 2015. Since then there have been many discussions on the mailing list and in-person at BFD WG meetings. The document has improved significantly based on the various suggestions. There is consistency on the technical content.

One action which has been postponed is updating the BFD YANG model to enable this functionality (requires a -bis of the BFD YANG document due to the new auth-type) 

There has been controversy because of the IPR Disclosure, see below.

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?

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, YANG 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?

The document is well-written, concise and technically accurate, but requires some editorial changes before being forwarded to the IESG.


Personnel:

Who is the Document Shepherd?
Reshad Rahman, BFD co-chair.

Who is the Responsible Area Director?
Martin Vigoureux 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.
The shepherd has gone through the document, email archive and meeting minutes. Comments have been addressed.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews that have been performed?
None.

(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.
This document was discussed with security experts. This led to draft-ietf-bfd-secure-numbers.


(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.
None

(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?
Yes

(8) Has an IPR disclosure been filed that references this document? If so, summarize any WG discussion and conclusion regarding the IPR disclosures.
https://datatracker.ietf.org/ipr/3328/
There has been controversy on the IPR disclosure on this document for 2 main reasons:
i) IPR disclosure was late (Nov 2018)
ii) The terms of the IPR
The IPR disclosure and terms were discussed at length on the mailing list and in the WG meetings:
https://datatracker.ietf.org/meeting/104/materials/minutes-104-bfd-00.pdf
https://datatracker.ietf.org/meeting/105/materials/minutes-105-bfd-02.pdf



(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?
Solid consensus on the technical aspects.
There is known opposition from 1 person (because of the IPR Disclosure).
https://mailarchive.ietf.org/arch/msg/rtg-bfd/u8rvWwvDWRKI3jseGHecAB9WtDo/


(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.)
None

(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.
3 warnings:
  == The copyright year in the IETF Trust and authors Copyright Line does not
    match the current year

  == The document seems to lack the recommended RFC 2119 boilerplate, even if
    it appears to use RFC 2119 keywords -- however, there's a paragraph with
    a matching beginning. Boilerplate error?

  == Outdated reference: A later version (-05) exists of
    draft-ietf-bfd-secure-sequence-numbers-04

Comment about document data being 186 days in the past.

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

(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?
None

(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.
None

(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.
No

(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 8126).
Assignment from the “BFD Authentication Types” registry requires Expert review. Checked https://www.iana.org/assignments/bfd-parameters/bfd-parameters.xhtml

(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.
None

(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, YANG modules, etc.
N/A

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) 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 RFC8342?
N/A


COMMENTS

General:
• Updates RFC5880 missing from title page
• Replace BFD frames by BFD packets or BFD control packets. Don’t use frames since RFC5880 uses packets.
• Use of term Null-authentication TLV. RFC5880 uses authentication section, doesn’t mention auth TLV.

Abstract:
Mention that this document updates RFC5880.

Requirements Language
Please put this is a separate (sub)section later, e.g. after introduction.

Introduction
First paragraph: s/is computationally intensive process/is a computationally intensive process/
Split first sentence into 2, e.g.
  Authenticating every BFD [RFC5880] packet with a Simple Password, or
  with a MD5 Message-Digest Algorithm [RFC1321], or Secure Hash
  Algorithm (SHA-1) algorithms is a computationally intensive process.
  This makes it difficult, if not impossible, to authenticate every packet,
  particularly at faster rates.

2nd paragraph: “… only BFD frames that signal a state change in BFD be authenticated.” State change is not 100% correct since P/F/D bit changes aren’t state changes (as mentioned in more detail below in section 2 comments). What about this instead: “State change, a demand mode change (to D bit) or a poll sequence change (P or F bit change) in a BFD packet are categorized as a significant BFD change. This document proposes that all BFD control packets which signal a significant BFD change MUST be authenticated if the session’s bfd.AuthType is non-zero. Other BFD control packets MAY be transmitted and received without the A bit set.” If you do use “significant BFD change”, add it to terminology section.
s/non-state change frame/BFD control packets without state or D/F/P bit change/, e.g.
“To detect a Man In the Middle (MITM) attack, it is also proposed that BFD control packets without a significant change be authenticated occasionally.  The interval of these control packets…”

Section 2
POLL and DEMAND are NOT strictly states. POLL refers to “Poll sequence” as specified in section 6.5 of RFC5880. DEMAND refers to “Demand mode” as specified in section 6.6 of RFC5880. In the table, the POLL entry refers to polling sequence enabled and in any BFD state. Likewise, the DEMAND entry refers to Demand mode. This means that a session in UP state, in demand mode and polling sequence enabled will match 3 entries in that table. It’s a bit confusing. Here’s what I suggest instead:
1. Take POLL out of the table. Add a paragraph mentioning that if P or F bit changes value, the packet MUST be authenticated
2. Take DEMAND out of the table. Add a paragraph mentioning that if D bit changes value, the packet MUST be authenticated

Another comment on the table. The text says it should be read as state change from column to row. Column INIT to row UP is n/a whereas column UP to row INIT is Auth. INIT to UP is a valid transition, UP to INIT is not (has to go through DOWN first). So I think those entries should be reversed in the table.

Last paragraph: CC frames is not defined in BFD, use “control packets” instead?

Section 3
Sequence number mentions “as defined in [RFC5880]”. Suggest mentioning bfd.XmitAuthSeq

Security Considerations.
I believe this needs to be beefed up:
1) Use of sequence number for non-authenticated frames. Secure sequence numbers even better.
2) Mention (again) that non-authenticated BFD packets which have a significant change (state, D/F/P) are dropped. So if someone injects a non-authenticated packet with Down state to take down the session, that won’t work.

Section 6.2
RFC5880 should be a normative reference.

=======================================================================================
Update December 31st 2024 on draft-ietf-bfd-optimizing-authentication-21

## 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 consensus of a few individuals.
The initial revision of this document is from 2015. Since then there have been multiple
discussions on the BFD alias and in in-person WG meetings. The "recent" changes to the
document to use ISAAC are the ones on which the WG has been mostly silent.

2. Was there controversy about particular points, or were there decisions where
  the consensus was particularly rough?

There has been controversy because of the IPR Disclosure, see below.

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)?

No implementations and no known plans to implement.

## 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 and 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.

The document has undergone a YANG Doctor 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?

Yes.

  If there are any resulting errors or warnings, what is
  the justification for not fixing them at this time?

No errors.

  Does the YANG module
  comply with the Network Management Datastore Architecture (NMDA) as specified
  in [RFC 8342][5]?

Yes.

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.

YANG has been validated.

## 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?

The document is clearly written and nearly ready.
There are some comments to be addressed before the document is handed off to the responsible AD.

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?

There has been a secdir review and comments have been addressed:
https://mailarchive.ietf.org/arch/msg/rtg-bfd/303D-DZ2DVFr9frgy75b6yyiILk/

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])?

Experimental as indicated on title page.

    Why is this the proper type
    of RFC?
Main reasons:
- No known implementations
- Not a lot of reviews on the latest revisions of the document

    Do all Datatracker state attributes correctly reflect this intent?
Yes.

12. Have reasonable efforts been made to remind all authors of the intellectual
    property rights (IPR) disclosure obligations described in [BCP 79][7]?
Yes.

    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.
Waiting for response from 1 co-author.


13. Has each author, editor, and contributor shown their willingness to be
    listed as such?
Yes.

    If the total number of authors and editors on the front page
    is greater than five, please provide a justification.
N/A.

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.)
  Miscellaneous warnings:
  ----------------------------------------------------------------------------

  == The document seems to lack the recommended RFC 2119 boilerplate, even if
    it appears to use RFC 2119 keywords -- however, there's a paragraph with
    a matching beginning. Boilerplate error?

    (The document does seem to have the reference to RFC 2119 which the
    ID-Checklist requires).
  -- The document date (21 October 2024) is 71 days in the past.  Is this
    intentional?

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?
N/A

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?
This document should be in the same bundle as draft-ietf-bfd-secure-sequence-numbers

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. This is an experimental document.

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]).
Section 6 matches the rest of the document and confirming the above where applicable.

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.
Assignment from the “BFD Authentication Types” registry requires Expert review. Checked https://www.iana.org/assignments/bfd-parameters/bfd-parameters.xhtml
There is also an updated IANA YANG module in the appendix.

[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/

=======================================================================================

Update Nov 23rd 2020

All comments have been addressed.

Update July 23rd 2020

Revised comments on draft-ietf-bfd-optimizing-authentication-10

General: both "BFD control packet" and "BFD packet" are used. I think we should stick to "BFD control packet".
General: s/BFD Control packet/BFD control packet/

Introduction, next-to last paragraph. Instead of "The interval of this non-state change frame can be...", I'd suggest "The interval of these BFD packets can be..." or "The interval of the BFD packets without a significant change can be...". Anyway remove "frame" as previously discussed and avoid use of "non-state change" now that you've defined what a significant change is.

Section 1.2. The new table could be incorrectly interpreted as having 1 entry. Suggest changing this to bullet form would make it clearer.

Section 1.2 introduces the term "configured interval" but section 2 uses the term "configured period". Also for the description, what about "interval at which BFD control packets are authenticated in the UP state".
Also wondering if instead we should have a new bfd.AuthUpStateInterval state variable (see 6.8.1 of RFC5880) since having this value may not always be configured (implementation specific)?

Section 2. Replace  "frame" by "packet" or "BFD control packet"  as appropriate.

Section 2. Thanks for modifying the table as per our discussions. Regarding adding AdminDown to the table, I believe I misled you. Our discussion was based on "what happens if we're UP and receive a packet which says AdminDown"? As per 6.2 of RFC5880, the receiver would go to DOWN state. However the rows/columns in the table are for the local state (new and old), and not for state in received packet. Since we can't go to AdminDown state or leave AdmnDown state based on a packet received, AdminDown state should be removed from this table . I think it'd be good to add a reference to the BFD FSM (6.8.2 of RFC5880) in the paragraph before the table.

Section 2. For configured period (or whatever we decide to call it) add a reference to section 1.2.

Section 4. s/to to/to/

=============================================================

(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?
Standards Track as indicated on title page.

(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:
This document describes an optimization to BFD Authentication as described in Section 6.7 of RFC5880. To remove the computational load on end-systems running BFD, it removes the requirement to authenticate all BFD control packets while providing a mechanism to keep the BFD sessions secure.

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.

Working Group Summary:
Initial revision of the document is from  February 2015. Since then there have been many discussions on the mailing list and in-person at BFD WG meetings. The document has improved significantly based on the various suggestions. There is consistency on the technical content.

One action which has been postponed is updating the BFD YANG model to enable this functionality (requires a -bis of the BFD YANG document due to the new auth-type) 

There has been controversy because of the IPR Disclosure, see below.

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?

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, YANG 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?

The document is well-written, concise and technically accurate, but requires some editorial changes before being forwarded to the IESG.


Personnel:

Who is the Document Shepherd?
Reshad Rahman, BFD co-chair.

Who is the Responsible Area Director?
Martin Vigoureux 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.
The shepherd has gone through the document, email archive and meeting minutes. Comments have been addressed.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews that have been performed?
None.

(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.
This document was discussed with security experts. This led to draft-ietf-bfd-secure-numbers.


(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.
None

(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?
Yes

(8) Has an IPR disclosure been filed that references this document? If so, summarize any WG discussion and conclusion regarding the IPR disclosures.
https://datatracker.ietf.org/ipr/3328/
There has been controversy on the IPR disclosure on this document for 2 main reasons:
i) IPR disclosure was late (Nov 2018)
ii) The terms of the IPR
The IPR disclosure and terms were discussed at length on the mailing list and in the WG meetings:
https://datatracker.ietf.org/meeting/104/materials/minutes-104-bfd-00.pdf
https://datatracker.ietf.org/meeting/105/materials/minutes-105-bfd-02.pdf



(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?
Solid consensus on the technical aspects.
There is known opposition from 1 person (because of the IPR Disclosure).
https://mailarchive.ietf.org/arch/msg/rtg-bfd/u8rvWwvDWRKI3jseGHecAB9WtDo/


(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.)
None

(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.
3 warnings:
  == The copyright year in the IETF Trust and authors Copyright Line does not
    match the current year

  == The document seems to lack the recommended RFC 2119 boilerplate, even if
    it appears to use RFC 2119 keywords -- however, there's a paragraph with
    a matching beginning. Boilerplate error?

  == Outdated reference: A later version (-05) exists of
    draft-ietf-bfd-secure-sequence-numbers-04

Comment about document data being 186 days in the past.

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

(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?
None

(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.
None

(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.
No

(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 8126).
Assignment from the “BFD Authentication Types” registry requires Expert review. Checked https://www.iana.org/assignments/bfd-parameters/bfd-parameters.xhtml

(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.
None

(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, YANG modules, etc.
N/A

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) 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 RFC8342?
N/A


COMMENTS

General:
• Updates RFC5880 missing from title page
• Replace BFD frames by BFD packets or BFD control packets. Don’t use frames since RFC5880 uses packets.
• Use of term Null-authentication TLV. RFC5880 uses authentication section, doesn’t mention auth TLV.

Abstract:
Mention that this document updates RFC5880.

Requirements Language
Please put this is a separate (sub)section later, e.g. after introduction.

Introduction
First paragraph: s/is computationally intensive process/is a computationally intensive process/
Split first sentence into 2, e.g.
  Authenticating every BFD [RFC5880] packet with a Simple Password, or
  with a MD5 Message-Digest Algorithm [RFC1321], or Secure Hash
  Algorithm (SHA-1) algorithms is a computationally intensive process.
  This makes it difficult, if not impossible, to authenticate every packet,
  particularly at faster rates.

2nd paragraph: “… only BFD frames that signal a state change in BFD be authenticated.” State change is not 100% correct since P/F/D bit changes aren’t state changes (as mentioned in more detail below in section 2 comments). What about this instead: “State change, a demand mode change (to D bit) or a poll sequence change (P or F bit change) in a BFD packet are categorized as a significant BFD change. This document proposes that all BFD control packets which signal a significant BFD change MUST be authenticated if the session’s bfd.AuthType is non-zero. Other BFD control packets MAY be transmitted and received without the A bit set.” If you do use “significant BFD change”, add it to terminology section.
s/non-state change frame/BFD control packets without state or D/F/P bit change/, e.g.
“To detect a Man In the Middle (MITM) attack, it is also proposed that BFD control packets without a significant change be authenticated occasionally.  The interval of these control packets…”

Section 2
POLL and DEMAND are NOT strictly states. POLL refers to “Poll sequence” as specified in section 6.5 of RFC5880. DEMAND refers to “Demand mode” as specified in section 6.6 of RFC5880. In the table, the POLL entry refers to polling sequence enabled and in any BFD state. Likewise, the DEMAND entry refers to Demand mode. This means that a session in UP state, in demand mode and polling sequence enabled will match 3 entries in that table. It’s a bit confusing. Here’s what I suggest instead:
1. Take POLL out of the table. Add a paragraph mentioning that if P or F bit changes value, the packet MUST be authenticated
2. Take DEMAND out of the table. Add a paragraph mentioning that if D bit changes value, the packet MUST be authenticated

Another comment on the table. The text says it should be read as state change from column to row. Column INIT to row UP is n/a whereas column UP to row INIT is Auth. INIT to UP is a valid transition, UP to INIT is not (has to go through DOWN first). So I think those entries should be reversed in the table.

Last paragraph: CC frames is not defined in BFD, use “control packets” instead?

Section 3
Sequence number mentions “as defined in [RFC5880]”. Suggest mentioning bfd.XmitAuthSeq

Security Considerations.
I believe this needs to be beefed up:
1) Use of sequence number for non-authenticated frames. Secure sequence numbers even better.
2) Mention (again) that non-authenticated BFD packets which have a significant change (state, D/F/P) are dropped. So if someone injects a non-authenticated packet with Down state to take down the session, that won’t work.

Section 6.2
RFC5880 should be a normative reference.

Update Nov 23rd 2020

All comments have been addressed.

Update July 23rd 2020

Revised comments on draft-ietf-bfd-optimizing-authentication-10

General: both "BFD control packet" and "BFD packet" are used. I think we should stick to "BFD control packet".
General: s/BFD Control packet/BFD control packet/

Introduction, next-to last paragraph. Instead of "The interval of this non-state change frame can be...", I'd suggest "The interval of these BFD packets can be..." or "The interval of the BFD packets without a significant change can be...". Anyway remove "frame" as previously discussed and avoid use of "non-state change" now that you've defined what a significant change is.

Section 1.2. The new table could be incorrectly interpreted as having 1 entry. Suggest changing this to bullet form would make it clearer.

Section 1.2 introduces the term "configured interval" but section 2 uses the term "configured period". Also for the description, what about "interval at which BFD control packets are authenticated in the UP state".
Also wondering if instead we should have a new bfd.AuthUpStateInterval state variable (see 6.8.1 of RFC5880) since having this value may not always be configured (implementation specific)?

Section 2. Replace  "frame" by "packet" or "BFD control packet"  as appropriate.

Section 2. Thanks for modifying the table as per our discussions. Regarding adding AdminDown to the table, I believe I misled you. Our discussion was based on "what happens if we're UP and receive a packet which says AdminDown"? As per 6.2 of RFC5880, the receiver would go to DOWN state. However the rows/columns in the table are for the local state (new and old), and not for state in received packet. Since we can't go to AdminDown state or leave AdmnDown state based on a packet received, AdminDown state should be removed from this table . I think it'd be good to add a reference to the BFD FSM (6.8.2 of RFC5880) in the paragraph before the table.

Section 2. For configured period (or whatever we decide to call it) add a reference to section 1.2.

Section 4. s/to to/to/

=============================================================

(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?
Standards Track as indicated on title page.

(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:
This document describes an optimization to BFD Authentication as described in Section 6.7 of RFC5880. To remove the computational load on end-systems running BFD, it removes the requirement to authenticate all BFD control packets while providing a mechanism to keep the BFD sessions secure.

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.

Working Group Summary:
Initial revision of the document is from  February 2015. Since then there have been many discussions on the mailing list and in-person at BFD WG meetings. The document has improved significantly based on the various suggestions. There is consistency on the technical content.

One action which has been postponed is updating the BFD YANG model to enable this functionality (requires a -bis of the BFD YANG document due to the new auth-type) 

There has been controversy because of the IPR Disclosure, see below.

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?

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, YANG 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?

The document is well-written, concise and technically accurate, but requires some editorial changes before being forwarded to the IESG.


Personnel:

Who is the Document Shepherd?
Reshad Rahman, BFD co-chair.

Who is the Responsible Area Director?
Martin Vigoureux 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.
The shepherd has gone through the document, email archive and meeting minutes. Comments have been addressed.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews that have been performed?
None.

(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.
This document was discussed with security experts. This led to draft-ietf-bfd-secure-numbers.


(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.
None

(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?
Yes

(8) Has an IPR disclosure been filed that references this document? If so, summarize any WG discussion and conclusion regarding the IPR disclosures.
https://datatracker.ietf.org/ipr/3328/
There has been controversy on the IPR disclosure on this document for 2 main reasons:
i) IPR disclosure was late (Nov 2018)
ii) The terms of the IPR
The IPR disclosure and terms were discussed at length on the mailing list and in the WG meetings:
https://datatracker.ietf.org/meeting/104/materials/minutes-104-bfd-00.pdf
https://datatracker.ietf.org/meeting/105/materials/minutes-105-bfd-02.pdf



(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?
Solid consensus on the technical aspects.
There is known opposition from 1 person (because of the IPR Disclosure).
https://mailarchive.ietf.org/arch/msg/rtg-bfd/u8rvWwvDWRKI3jseGHecAB9WtDo/


(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.)
None

(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.
3 warnings:
  == The copyright year in the IETF Trust and authors Copyright Line does not
    match the current year

  == The document seems to lack the recommended RFC 2119 boilerplate, even if
    it appears to use RFC 2119 keywords -- however, there's a paragraph with
    a matching beginning. Boilerplate error?

  == Outdated reference: A later version (-05) exists of
    draft-ietf-bfd-secure-sequence-numbers-04

Comment about document data being 186 days in the past.

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

(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?
None

(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.
None

(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.
No

(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 8126).
Assignment from the “BFD Authentication Types” registry requires Expert review. Checked https://www.iana.org/assignments/bfd-parameters/bfd-parameters.xhtml

(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.
None

(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, YANG modules, etc.
N/A

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) 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 RFC8342?
N/A


COMMENTS

General:
• Updates RFC5880 missing from title page
• Replace BFD frames by BFD packets or BFD control packets. Don’t use frames since RFC5880 uses packets.
• Use of term Null-authentication TLV. RFC5880 uses authentication section, doesn’t mention auth TLV.

Abstract:
Mention that this document updates RFC5880.

Requirements Language
Please put this is a separate (sub)section later, e.g. after introduction.

Introduction
First paragraph: s/is computationally intensive process/is a computationally intensive process/
Split first sentence into 2, e.g.
  Authenticating every BFD [RFC5880] packet with a Simple Password, or
  with a MD5 Message-Digest Algorithm [RFC1321], or Secure Hash
  Algorithm (SHA-1) algorithms is a computationally intensive process.
  This makes it difficult, if not impossible, to authenticate every packet,
  particularly at faster rates.

2nd paragraph: “… only BFD frames that signal a state change in BFD be authenticated.” State change is not 100% correct since P/F/D bit changes aren’t state changes (as mentioned in more detail below in section 2 comments). What about this instead: “State change, a demand mode change (to D bit) or a poll sequence change (P or F bit change) in a BFD packet are categorized as a significant BFD change. This document proposes that all BFD control packets which signal a significant BFD change MUST be authenticated if the session’s bfd.AuthType is non-zero. Other BFD control packets MAY be transmitted and received without the A bit set.” If you do use “significant BFD change”, add it to terminology section.
s/non-state change frame/BFD control packets without state or D/F/P bit change/, e.g.
“To detect a Man In the Middle (MITM) attack, it is also proposed that BFD control packets without a significant change be authenticated occasionally.  The interval of these control packets…”

Section 2
POLL and DEMAND are NOT strictly states. POLL refers to “Poll sequence” as specified in section 6.5 of RFC5880. DEMAND refers to “Demand mode” as specified in section 6.6 of RFC5880. In the table, the POLL entry refers to polling sequence enabled and in any BFD state. Likewise, the DEMAND entry refers to Demand mode. This means that a session in UP state, in demand mode and polling sequence enabled will match 3 entries in that table. It’s a bit confusing. Here’s what I suggest instead:
1. Take POLL out of the table. Add a paragraph mentioning that if P or F bit changes value, the packet MUST be authenticated
2. Take DEMAND out of the table. Add a paragraph mentioning that if D bit changes value, the packet MUST be authenticated

Another comment on the table. The text says it should be read as state change from column to row. Column INIT to row UP is n/a whereas column UP to row INIT is Auth. INIT to UP is a valid transition, UP to INIT is not (has to go through DOWN first). So I think those entries should be reversed in the table.

Last paragraph: CC frames is not defined in BFD, use “control packets” instead?

Section 3
Sequence number mentions “as defined in [RFC5880]”. Suggest mentioning bfd.XmitAuthSeq

Security Considerations.
I believe this needs to be beefed up:
1) Use of sequence number for non-authenticated frames. Secure sequence numbers even better.
2) Mention (again) that non-authenticated BFD packets which have a significant change (state, D/F/P) are dropped. So if someone injects a non-authenticated packet with Down state to take down the session, that won’t work.

Section 6.2
RFC5880 should be a normative reference.

Update July 23rd 2020

Revised comments on draft-ietf-bfd-optimizing-authentication-10

General: both "BFD control packet" and "BFD packet" are used. I think we should stick to "BFD control packet".
General: s/BFD Control packet/BFD control packet/

Introduction, next-to last paragraph. Instead of "The interval of this non-state change frame can be...", I'd suggest "The interval of these BFD packets can be..." or "The interval of the BFD packets without a significant change can be...". Anyway remove "frame" as previously discussed and avoid use of "non-state change" now that you've defined what a significant change is.

Section 1.2. The new table could be incorrectly interpreted as having 1 entry. Suggest changing this to bullet form would make it clearer.

Section 1.2 introduces the term "configured interval" but section 2 uses the term "configured period". Also for the description, what about "interval at which BFD control packets are authenticated in the UP state".
Also wondering if instead we should have a new bfd.AuthUpStateInterval state variable (see 6.8.1 of RFC5880) since having this value may not always be configured (implementation specific)?

Section 2. Replace  "frame" by "packet" or "BFD control packet"  as appropriate.

Section 2. Thanks for modifying the table as per our discussions. Regarding adding AdminDown to the table, I believe I misled you. Our discussion was based on "what happens if we're UP and receive a packet which says AdminDown"? As per 6.2 of RFC5880, the receiver would go to DOWN state. However the rows/columns in the table are for the local state (new and old), and not for state in received packet. Since we can't go to AdminDown state or leave AdmnDown state based on a packet received, AdminDown state should be removed from this table . I think it'd be good to add a reference to the BFD FSM (6.8.2 of RFC5880) in the paragraph before the table.

Section 2. For configured period (or whatever we decide to call it) add a reference to section 1.2.

Section 4. s/to to/to/

=============================================================

(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?
Standards Track as indicated on title page.

(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:
This document describes an optimization to BFD Authentication as described in Section 6.7 of RFC5880. To remove the computational load on end-systems running BFD, it removes the requirement to authenticate all BFD control packets while providing a mechanism to keep the BFD sessions secure.

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.

Working Group Summary:
Initial revision of the document is from  February 2015. Since then there have been many discussions on the mailing list and in-person at BFD WG meetings. The document has improved significantly based on the various suggestions. There is consistency on the technical content.

One action which has been postponed is updating the BFD YANG model to enable this functionality (requires a -bis of the BFD YANG document due to the new auth-type) 

There has been controversy because of the IPR Disclosure, see below.

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?

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, YANG 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?

The document is well-written, concise and technically accurate, but requires some editorial changes before being forwarded to the IESG.


Personnel:

Who is the Document Shepherd?
Reshad Rahman, BFD co-chair.

Who is the Responsible Area Director?
Martin Vigoureux 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.
The shepherd has gone through the document, email archive and meeting minutes. Comments have been addressed.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews that have been performed?
None.

(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.
This document was discussed with security experts. This led to draft-ietf-bfd-secure-numbers.


(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.
None

(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?
Yes

(8) Has an IPR disclosure been filed that references this document? If so, summarize any WG discussion and conclusion regarding the IPR disclosures.
https://datatracker.ietf.org/ipr/3328/
There has been controversy on the IPR disclosure on this document for 2 main reasons:
i) IPR disclosure was late (Nov 2018)
ii) The terms of the IPR
The IPR disclosure and terms were discussed at length on the mailing list and in the WG meetings:
https://datatracker.ietf.org/meeting/104/materials/minutes-104-bfd-00.pdf
https://datatracker.ietf.org/meeting/105/materials/minutes-105-bfd-02.pdf



(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?
Solid consensus on the technical aspects.
There is known opposition from 1 person (because of the IPR Disclosure).
https://mailarchive.ietf.org/arch/msg/rtg-bfd/u8rvWwvDWRKI3jseGHecAB9WtDo/


(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.)
None

(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.
3 warnings:
  == The copyright year in the IETF Trust and authors Copyright Line does not
    match the current year

  == The document seems to lack the recommended RFC 2119 boilerplate, even if
    it appears to use RFC 2119 keywords -- however, there's a paragraph with
    a matching beginning. Boilerplate error?

  == Outdated reference: A later version (-05) exists of
    draft-ietf-bfd-secure-sequence-numbers-04

Comment about document data being 186 days in the past.

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

(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?
None

(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.
None

(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.
No

(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 8126).
Assignment from the “BFD Authentication Types” registry requires Expert review. Checked https://www.iana.org/assignments/bfd-parameters/bfd-parameters.xhtml

(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.
None

(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, YANG modules, etc.
N/A

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) 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 RFC8342?
N/A


COMMENTS

General:
• Updates RFC5880 missing from title page
• Replace BFD frames by BFD packets or BFD control packets. Don’t use frames since RFC5880 uses packets.
• Use of term Null-authentication TLV. RFC5880 uses authentication section, doesn’t mention auth TLV.

Abstract:
Mention that this document updates RFC5880.

Requirements Language
Please put this is a separate (sub)section later, e.g. after introduction.

Introduction
First paragraph: s/is computationally intensive process/is a computationally intensive process/
Split first sentence into 2, e.g.
  Authenticating every BFD [RFC5880] packet with a Simple Password, or
  with a MD5 Message-Digest Algorithm [RFC1321], or Secure Hash
  Algorithm (SHA-1) algorithms is a computationally intensive process.
  This makes it difficult, if not impossible, to authenticate every packet,
  particularly at faster rates.

2nd paragraph: “… only BFD frames that signal a state change in BFD be authenticated.” State change is not 100% correct since P/F/D bit changes aren’t state changes (as mentioned in more detail below in section 2 comments). What about this instead: “State change, a demand mode change (to D bit) or a poll sequence change (P or F bit change) in a BFD packet are categorized as a significant BFD change. This document proposes that all BFD control packets which signal a significant BFD change MUST be authenticated if the session’s bfd.AuthType is non-zero. Other BFD control packets MAY be transmitted and received without the A bit set.” If you do use “significant BFD change”, add it to terminology section.
s/non-state change frame/BFD control packets without state or D/F/P bit change/, e.g.
“To detect a Man In the Middle (MITM) attack, it is also proposed that BFD control packets without a significant change be authenticated occasionally.  The interval of these control packets…”

Section 2
POLL and DEMAND are NOT strictly states. POLL refers to “Poll sequence” as specified in section 6.5 of RFC5880. DEMAND refers to “Demand mode” as specified in section 6.6 of RFC5880. In the table, the POLL entry refers to polling sequence enabled and in any BFD state. Likewise, the DEMAND entry refers to Demand mode. This means that a session in UP state, in demand mode and polling sequence enabled will match 3 entries in that table. It’s a bit confusing. Here’s what I suggest instead:
1. Take POLL out of the table. Add a paragraph mentioning that if P or F bit changes value, the packet MUST be authenticated
2. Take DEMAND out of the table. Add a paragraph mentioning that if D bit changes value, the packet MUST be authenticated

Another comment on the table. The text says it should be read as state change from column to row. Column INIT to row UP is n/a whereas column UP to row INIT is Auth. INIT to UP is a valid transition, UP to INIT is not (has to go through DOWN first). So I think those entries should be reversed in the table.

Last paragraph: CC frames is not defined in BFD, use “control packets” instead?

Section 3
Sequence number mentions “as defined in [RFC5880]”. Suggest mentioning bfd.XmitAuthSeq

Security Considerations.
I believe this needs to be beefed up:
1) Use of sequence number for non-authenticated frames. Secure sequence numbers even better.
2) Mention (again) that non-authenticated BFD packets which have a significant change (state, D/F/P) are dropped. So if someone injects a non-authenticated packet with Down state to take down the session, that won’t work.

Section 6.2
RFC5880 should be a normative reference.

(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?
Standards Track as indicated on title page.

(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:
This document describes an optimization to BFD Authentication as described in Section 6.7 of RFC5880. To remove the computational load on end-systems running BFD, it removes the requirement to authenticate all BFD control packets while providing a mechanism to keep the BFD sessions secure.

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.

Working Group Summary:
Initial revision of the document is from  February 2015. Since then there have been many discussions on the mailing list and in-person at BFD WG meetings. The document has improved significantly based on the various suggestions. There is consistency on the technical content.

One action which has been postponed is updating the BFD YANG model to enable this functionality (requires a -bis of the BFD YANG document due to the new auth-type) 

There has been controversy because of the IPR Disclosure, see below.

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?

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, YANG 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?

The document is well-written, concise and technically accurate, but requires some editorial changes before being forwarded to the IESG.


Personnel:

Who is the Document Shepherd?
Reshad Rahman, BFD co-chair.

Who is the Responsible Area Director?
Martin Vigoureux 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.
The shepherd has gone through the document, email archive and meeting minutes. Comments have been addressed.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews that have been performed?
None.

(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.
This document was discussed with security experts. This led to draft-ietf-bfd-secure-numbers.


(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.
None

(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?
Yes

(8) Has an IPR disclosure been filed that references this document? If so, summarize any WG discussion and conclusion regarding the IPR disclosures.
https://datatracker.ietf.org/ipr/3328/
There has been controversy on the IPR disclosure on this document for 2 main reasons:
i) IPR disclosure was late (Nov 2018)
ii) The terms of the IPR
The IPR disclosure and terms were discussed at length on the mailing list and in the WG meetings:
https://datatracker.ietf.org/meeting/104/materials/minutes-104-bfd-00.pdf
https://datatracker.ietf.org/meeting/105/materials/minutes-105-bfd-02.pdf



(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?
Solid consensus on the technical aspects.
There is known opposition from 1 person (because of the IPR Disclosure).
https://mailarchive.ietf.org/arch/msg/rtg-bfd/u8rvWwvDWRKI3jseGHecAB9WtDo/


(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.)
None

(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.
3 warnings:
  == The copyright year in the IETF Trust and authors Copyright Line does not
    match the current year

  == The document seems to lack the recommended RFC 2119 boilerplate, even if
    it appears to use RFC 2119 keywords -- however, there's a paragraph with
    a matching beginning. Boilerplate error?

  == Outdated reference: A later version (-05) exists of
    draft-ietf-bfd-secure-sequence-numbers-04

Comment about document data being 186 days in the past.

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

(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?
None

(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.
None

(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.
No

(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 8126).
Assignment from the “BFD Authentication Types” registry requires Expert review. Checked https://www.iana.org/assignments/bfd-parameters/bfd-parameters.xhtml

(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.
None

(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, YANG modules, etc.
N/A

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) 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 RFC8342?
N/A


COMMENTS

General:
• Updates RFC5880 missing from title page
• Replace BFD frames by BFD packets or BFD control packets. Don’t use frames since RFC5880 uses packets.
• Use of term Null-authentication TLV. RFC5880 uses authentication section, doesn’t mention auth TLV.

Abstract:
Mention that this document updates RFC5880.

Requirements Language
Please put this is a separate (sub)section later, e.g. after introduction.

Introduction
First paragraph: s/is computationally intensive process/is a computationally intensive process/
Split first sentence into 2, e.g.
  Authenticating every BFD [RFC5880] packet with a Simple Password, or
  with a MD5 Message-Digest Algorithm [RFC1321], or Secure Hash
  Algorithm (SHA-1) algorithms is a computationally intensive process.
  This makes it difficult, if not impossible, to authenticate every packet,
  particularly at faster rates.

2nd paragraph: “… only BFD frames that signal a state change in BFD be authenticated.” State change is not 100% correct since P/F/D bit changes aren’t state changes (as mentioned in more detail below in section 2 comments). What about this instead: “State change, a demand mode change (to D bit) or a poll sequence change (P or F bit change) in a BFD packet are categorized as a significant BFD change. This document proposes that all BFD control packets which signal a significant BFD change MUST be authenticated if the session’s bfd.AuthType is non-zero. Other BFD control packets MAY be transmitted and received without the A bit set.” If you do use “significant BFD change”, add it to terminology section.
s/non-state change frame/BFD control packets without state or D/F/P bit change/, e.g.
“To detect a Man In the Middle (MITM) attack, it is also proposed that BFD control packets without a significant change be authenticated occasionally.  The interval of these control packets…”

Section 2
POLL and DEMAND are NOT strictly states. POLL refers to “Poll sequence” as specified in section 6.5 of RFC5880. DEMAND refers to “Demand mode” as specified in section 6.6 of RFC5880. In the table, the POLL entry refers to polling sequence enabled and in any BFD state. Likewise, the DEMAND entry refers to Demand mode. This means that a session in UP state, in demand mode and polling sequence enabled will match 3 entries in that table. It’s a bit confusing. Here’s what I suggest instead:
1. Take POLL out of the table. Add a paragraph mentioning that if P or F bit changes value, the packet MUST be authenticated
2. Take DEMAND out of the table. Add a paragraph mentioning that if D bit changes value, the packet MUST be authenticated

Another comment on the table. The text says it should be read as state change from column to row. Column INIT to row UP is n/a whereas column UP to row INIT is Auth. INIT to UP is a valid transition, UP to INIT is not (has to go through DOWN first). So I think those entries should be reversed in the table.

Last paragraph: CC frames is not defined in BFD, use “control packets” instead?

Section 3
Sequence number mentions “as defined in [RFC5880]”. Suggest mentioning bfd.XmitAuthSeq

Security Considerations.
I believe this needs to be beefed up:
1) Use of sequence number for non-authenticated frames. Secure sequence numbers even better.
2) Mention (again) that non-authenticated BFD packets which have a significant change (state, D/F/P) are dropped. So if someone injects a non-authenticated packet with Down state to take down the session, that won’t work.

Section 6.2
RFC5880 should be a normative reference.