Shepherd writeup
draft-ietf-bfd-secure-sequence-numbers-06

(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 a security enhancement for the sequence number used in BFD control packets. 

Working Group Summary:
Initial version of the document is from February 2017. Goal was to address concerns expressed by Security Area on the work to optimize BFD authentication (draft-ietf-bfd-optimizing-authentication).
There have not been many comments on this draft specifically, but there have been many discussions on what this draft provides in the context of draft-ietf-bfd-optimizing-authentication. 
One action which has been postponed is updating the BFD YANG model to enable this functionality, this is needed also for  draft-ietf-bfd-optimizing-authentication (although the latter requires a -bis of the BFD YANG document due to the new auth-type)  

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 arose from Security Area review of draft-ietf-bfd-optimizing-authentication. 

(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. 
No IPR disclosure

(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? 
WG consensus is solid.

(10) Has anyone threatened an appeal or otherwise indicated extreme discontent? If so, please summarise the areas of conflict in separate email messages to the Responsible Area Director. (It should be in a separate email because this questionnaire is publicly available.) 
No

(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. 
1 comment about the document data being 106 days in the past.
4 warnings about missing references for [O], [S], [A] and [H1] (mentioned but not defined). I think if e.g. <> is used instead of [] this warnings will go away.

(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? 
No

(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). 
No protocol extensions which require a registry.

(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. 
N/A

(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

This document updates RFC5880. This is missing from the title page header.

Abstract
s/a security enhancements/a security enhancement/
Suggestion: “This document describes a security enhancement for the sequence number used in BFD control packets”.

Requirements Language
Please put this later in the document, e.g. after introduction. Add RFC8174, and add it as normative reference.

Introduction
Don’t use Authentication TLV, instead use “Authentication Section”. E.g.
s/in BFD authentication TLVs/in the BFD authentication section/


s/pseudo-random sequence numbers on the frame/pseudo-random sequence numbers in BFD control packets/
I’m not sure I understood the last sentence starting with “Further security may be ….”. What is “resetting un-encrypted sequence”? Does it mean that when the sequence numbers rolls over, it’s reset to a pseudo-random number?

Section 2
Rename to “Theory of operation”
Suggest splitting the  1st sentence, e.g.
   Instead of inserting a monotonically, sometimes occasionally, increasing 
   sequence number in BFD control packets, a hash is inserted instead.
   The hash is computed, using a shared key, on the sequence number. That
   computed hash is then inserted into the sequence number field of the 
   packet.

In the following sentence, the part “used in computing an authenticated packet” is referring to computing the SHA1/MD5 hash/digest for the packet? That sentence should be clarified then.
                                                                   In
   case of BFD Authentication [I-D.ietf-bfd-optimizing-authentication],
   the sequence number used in computing an authenticated packet would
   be this new computed hash.

Also, when referring to the optimization draft, better to use e.g. “optimized BFD authentication” than “BFD authentication”. The latter implies per-RFC5880 BFD authentication.

s/psuedo/pseudo/
s/ scope of this draft/ scope of this document/
s/seuquence/sequence/

Not clear to me what the following means.
                              Note: The first sequence number can
   be obtained using the same logic as the My Discriminator value. 

The diagram reads well for regular authentication. For secure sequence number, I think the diagram would gain clarity from an ordered list of steps on the sender and receiver. The current list before the diagram is useful,  I believe the sender steps would start at “H1:” and the receiver steps at hash’. And yes, hash’ needs an explanation. On the receiver side, for validating that ’s’ is a good sequence number, the range has to be checked as mentioned in the previous paragraph.

Section 5
s/ stabiluty/ stability/
s/admistratively/administratively/
s/Sequential nature/The sequential nature/

Back