Concise Binary Object Representation (CBOR) Tags for Time, Duration, and Period
draft-ietf-cbor-time-tag-12

[Ballot discuss]
Section 7.2 establishes a new IANA registry using "a combination of "Expert Review" and "RFC Required" as the Registration Procedure".  How are they combined?  Is it either-or?  Do different ranges have different policies?  Does the applicant get to choose?  Does the designated expert get to choose?

[Ballot discuss]
Hi,

Thanks for this document, I have a few "discuss" level comments:

Moderate level comments:

(1) p 0, sec

  The Concise Binary Object Representation (CBOR, RFC 8949) is a data
  format whose design goals include the possibility of extremely small
  code size, fairly small message size, and extensibility without the
  need for version negotiation.

My main concern here is the risk that introducing these new time encodings could end reducing interoperability.  My initial reading is that these new types are more flexible, contain more information, and hence require more code to parse and understand than say the tag 1 type, and hence may not be so widely understood and used by implementations.  Hence, please can the authors consider whether there should be a recommendation to use time type 1 in preference, and only use the extended time types where required?  Or conversely, encourage everyone to move to a particular variant of the new extended time type.

(2)
Related to my previous comment, I have a question about normalization or canonicalization.  The new extended time type allows the same time to be represented in multiple different ways (e.g., int, binary float, decimal float, split secs + fraction).  Does any guidance need to be given if canonicalization is required?


(3) p 12, sec 4.  Duration Format

  Semantically, they do not measure the time elapsed from a given
  epoch, but from the start to the end of (an otherwise unspecified)
  interval of time.

Are any of the fields defined in etime-detailed not appropriate for a duration, and if so should they be listed and what should a receiver do if they receive them?  Or is the only rational choice here that is has to be down to the application to decide how to handle this case?  Either way, is any additional text needed here?

[Ballot comment]
Minor level comments:

(4) p 13, sec 5.  Period Format

  Period = #6.1003([
    start: ~Etime / null
    end: ~Etime / null
    ? duration: ~Duration / null
  ])
  If the third array element is not given, the duration element is
  null.  Exactly two out of the three elements must be non-null, this
  can be somewhat verbosely expressed in CDDL as:

I found it harder (but not impossible) to understanding the intended encoding here.  Also, rather than allowing duration to be null, or missing (i.e., len 2 array), would it better to choose just one of these encodings, or otherwise do you need to consider canonicalization of start/end periods?

Perhaps splitting this into two paragraphs would be easier to read/explain.  E.g.,

  A period can be represented by a start and end time, in which case it is represented as an array of two elements.

  Alternatively, a period can be represented as a start time with duration or an end time with duration.  This is represented as an array of 3 elements where either the start or end time MUST be set to null.

Regards,
Rob

[Ballot comment]

# Éric Vyncke, INT AD, comments for draft-ietf-cbor-time-tag-11

Thank you for the work put into this document. I am trusting the responsible AD for the CDDL specifications, please also note that I am not a time specialist.

Please find below some non-blocking COMMENT points (but replies would be appreciated even if only for my own education).

Special thanks to Barry Leiba for the shepherd's minimalist write-up including the WG consensus and the justification of the intended status.

Other thanks to Qin Wu, the IoT directorate reviewer (at my request), please consider this int-dir review:
https://datatracker.ietf.org/doc/review-ietf-cbor-time-tag-10-iotdir-telechat-wu-2023-10-17/ (and I have read the follow-up email discussion)

I hope that this review helps to improve the document,

Regards,

-éric

# COMMENTS

## Section 2

What is "TAI" ?

## Section 3

As non native English speaker, I find this clause unclear: `these keys are "elective", as the extended time is still usable if an implementation elects not to implement them` I.e., how can it be usable if the implementation does not support it ? Is it because the added information is not critical ?

## Section 3.3

Should there be a reference for Haskell time ?

## Section 3.4

Please add an informative reference to NTP.

More important, "GPS" is a specific system out of the USA. Please use "GNSS" as it also covers non-USA satellite systems such as Galileo.

[Ballot comment]
# Internet AD comments for draft-ietf-cbor-time-tag-11
CC @ekline

* comment syntax:
  - https://github.com/mnot/ietf-comments/blob/main/format.md

* "Handling Ballot Positions":
  - https://ietf.org/about/groups/iesg/statements/handling-ballot-positions/

## Comments

### S4

* With this definition of Duration, it seems like implementers might need
  to support a duration with an accompanying critical Time Zone Hint, is
  that correct?


  Seems ... odd, but I understand the desire for de-duplication.

[Ballot comment]
NITS:

TAI is never expanded - expand on first use? At least for me this was a new term, unlike UTC. But perhaps it is obvious for implementers in this space.

        The present document

Use "This document"

        therefore is rendered by the surrogate notation seen here in the plain-text rendition.

"here" is a bit weird when I'm reading the HTML version. Can't you just write 2^xx as an example ?


        The security considerations of RFC 8949 apply

A link is missing here.

[Ballot comment]
** Section 2. 
  For example, map keys could be registered for direct representations
  of natural platform time formats.

What are “natural platform time formats”?

** Section 3.
  The map must contain exactly one unsigned integer key that specifies
  the "base time", and may also contain one or more negative integer or
  text-string keys, which may encode supplementary information.

Should a normative MUST and MAY be used here?

** Section 8. 
  Time, of course, has significant security considerations; these
  include the exploitation of ambiguities where time is security
  relevant (e.g., for freshness or in a validity span) or the
  disclosure of characteristics of the emitting system (e.g., time
  zone, or clock resolution and wall clock offset).

Recommend citing the Security Considerations of draft-ietf-sedate-datetime-extended.  The text there covers a number of the topics mentioned above.

(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

IANA has completed its review of draft-ietf-cbor-time-tag-10. If any part of this review is inaccurate, please let us know.

IANA has questions about the second and third actions requested.

IANA understands that, upon approval of this document, there are three actions which we must complete.

First, in the CBOR Tags registry in the Concise Binary Object Representation (CBOR) Tags registry group located at:

https://www.iana.org/assignments/cbor-tags/

three early registrations will have their references changed to [ RFC-to-be ] as follows:

Tag: 1001
Data Item: map
Semantics: extended time
Reference: [ RFC-to-be ]

Tag: 1002
Data Item: map
Semantics: duration
Reference: [ RFC-to-be ]

Tag: 1003
Data Item: array
Semantics: period
Reference: [ RFC-to-be ]

We note that the "Data Item" entry for Tag 1003 is changed from "map" to "array."

Second, a new registry is to be created called the Timescales registry. The new registry is to be located in the Concise Binary Object Representation (CBOR) Tags registry group located at:

https://www.iana.org/assignments/cbor-tags/

The new registry will be managed via Expert Review AND RFC Required as defined in [RFC8126]. Each assignment in the registry will consist of a timescale name (a sequence of uppercase ASCII characters and digits, where a digit may not occur at the start: [A-Z][A-Z0-9]*), a value (CBOR unsigned integer, uint), and brief description of the semantics, and a specification reference (RFC).

IANA Question -> What are the minimum and maximum values for this registry?

There are initial registrations in the new registry as follows:

Timescale Value Semantics Reference
----------+-----+----------+-------------
UTC 0 UTC with POSIX Epoch [ RFC-to-be ]
TAI 1 TAI with PTP Epoch [ RFC-to-be ]

Third, a new registry is to be created called the Time Tag Map Keys registry. The new registry is to be located in the Concise Binary Object Representation (CBOR) Tags registry group located at:

https://www.iana.org/assignments/cbor-tags/

The new registry will be managed via Specification Required as defined in [RFC8126]. Each assignment in the new registry will consist of a map key value (CBOR integer, int), a brief description of the semantics, and a specification reference (RFC).

IANA Question -> What are the minimum and maximum values for this registry?

There are initial registrations in the new registry as follows:

Value Semantics Reference
-----+----------+-----------------
-18 attoseconds [ RFC-to-be ]
-15 femtoseconds [ RFC-to-be ]
-12 picoseconds [ RFC-to-be ]
-11 IXDTF Suffix Information (elective) [ RFC-to-be ], [IXDTF]
-10 IXDTF Time Zone Hint (elective) [ RFC-to-be ], [IXDTF]
-9 nanoseconds [ RFC-to-be ]
-8 Guarantee [ RFC-to-be ]
-7 Uncertainty [ RFC-to-be ]
-6 microseconds [ RFC-to-be ]
-5 Offset-Scaled Log Variance [ RFC-to-be ]
-4 Clock Accuracy [ RFC-to-be ]
-3 milliseconds [ RFC-to-be ]
-2 Clock Class [ RFC-to-be ]
1 Base Time value as in CBOR Tag 1 [RFC8949] [ RFC-to-be ]
4 Base Time value as in CBOR Tag 4 [RFC8949] [ RFC-to-be ]
5 Base Time value as in CBOR Tag 5 [RFC8949] [ RFC-to-be ]
10 IXDTF Time Zone Hint (critical) [ RFC-to-be ], [IXDTF]
11 IXDTF Suffix Information (critical) [ RFC-to-be ], [IXDTF]

We understand that these are the only actions required to be completed upon approval of this document.

NOTE: The actions requested in this document will not be completed until the document has been approved for publication as an RFC. This message is meant only to confirm the list of actions that will be performed.

For definitions of IANA review states, please see:

https://datatracker.ietf.org/help/state/draft/iana-review

Thank you,

David Dong
IANA Services Sr. Specialist

The following Last Call announcement was sent out (ends 2023-10-21):

From: The IESG
To: IETF-Announce
CC: barryleiba@computer.org, cbor-chairs@ietf.org, cbor@ietf.org, draft-ietf-cbor-time-tag@ietf.org, francesca.palombini@ericsson.com
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (Concise Binary Object Representation (CBOR) Tags for Time, Duration, and Period) to Proposed Standard


The IESG has received a request from the Concise Binary Object Representation
Maintenance and Extensions WG (cbor) to consider the following document: -
'Concise Binary Object Representation (CBOR) Tags for Time, Duration,
  and Period'
  as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits final
comments on this action. Please send substantive comments to the
last-call@ietf.org mailing lists by 2023-10-21. Exceptionally, comments may
be sent to iesg@ietf.org instead. In either case, please retain the beginning
of the Subject line to allow automated sorting.

Abstract


  The Concise Binary Object Representation (CBOR, RFC 8949) is a data
  format whose design goals include the possibility of extremely small
  code size, fairly small message size, and extensibility without the
  need for version negotiation.

  In CBOR, one point of extensibility is the definition of CBOR tags.
  RFC 8949 defines two tags for time: CBOR tag 0 (RFC3339 time as a
  string) and tag 1 (Posix time as int or float).  Since then,
  additional requirements have become known.  The present document
  defines a CBOR tag for time that allows a more elaborate
  representation of time, as well as related CBOR tags for duration and
  time period.  It is intended as the reference document for the IANA
  registration of the CBOR tags defined.


  // The present version (-10) addresses comments and WG discussion
  // during the AD review.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-cbor-time-tag/



No IPR declarations have been submitted directly on this I-D.

## Document History

1. Does the working group (WG) consensus represent the strong concurrence of a
  few individuals, with others being silent, or did it reach broad agreement?

  The document has broad agreement from the active working group.

2. Was there controversy about particular points, or were there decisions where
  the consensus was particularly rough?
 
  No.

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)?
 
  There are early implementations, though they are not listed.  The document is
  expected to get wide adoption.

## 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.
 
  There has been coordination with the SEDATE working group and its document
  draft-ietf-sedate-datetime-extended.  This document is ready to proceed, but
  there is still a normative reference to the SEDATE document.

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

7. If the document contains a YANG module, has the final version of the module
  been checked with any of the [recommended validation tools][4] for syntax and
  formatting validation? If there are any resulting errors or warnings, what is
  the justification for not fixing them at this time? Does the YANG module
  comply with the Network Management Datastore Architecture (NMDA) as specified
  in [RFC 8342][5]?
 
  N/A

8. Describe reviews and automated checks performed to validate sections of the
  final version of the document written in a formal language, such as XML code,
  BNF rules, MIB definitions, CBOR's CDDL, etc.
 
  As a product of the CBOR working group, the document has been reviewed by the
  CBOR experts.  There is some simple ABNF in it, which does not need expert
  review.

## Document Shepherd Checks

9. Based on the shepherd's review of the document, is it their opinion that this
  document is needed, clearly written, complete, correctly designed, and ready
  to be handed off to the responsible Area Director?
 
  Yes.

10. Several IETF Areas have assembled [lists of common issues that their
    reviewers encounter][6]. For which areas have such issues been identified
    and addressed? For which does this still need to happen in subsequent
    reviews?
   
    None identified.

11. What type of RFC publication is being requested on the IETF stream ([Best
    Current Practice][12], [Proposed Standard, Internet Standard][13],
    [Informational, Experimental or Historic][14])? Why is this the proper type
    of RFC? Do all Datatracker state attributes correctly reflect this intent?
   
    The document is aimed at Proposed Standard, providing standards-track guidance
    on CBOR time tags and an anchor for IANA registrations.  This is set in the
    datatracker after the working group decided to go for Standards Track (it was
    originally planned as Informational).

12. Have reasonable efforts been made to remind all authors of the intellectual
    property rights (IPR) disclosure obligations described in [BCP 79][7]? To
    the best of your knowledge, have all required disclosures been filed? If
    not, explain why. If yes, summarize any relevant discussion, including links
    to publicly-available messages when applicable.
   
    Yes.

13. Has each author, editor, and contributor shown their willingness to be
    listed as such? If the total number of authors and editors on the front page
    is greater than five, please provide a justification.
   
    Yes, and 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.)
   
    N/A

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?
   
    IEEE 1588-2008, "IEEE Standard for a Precision Clock Synchronization Protocol
    for Networked Measurement and Control Systems" requires payment or subscription.
    It is used in other IETF documents.
   
    JCGM 100:2008, "Evaluation of measurement data — Guide to the expression of
    uncertainty in measurement" is a product of the Joint Committee for Guides in
    Metrology.  It is freely available.

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?
   
    draft-ietf-sedate-datetime-extended is in the SEDATE working group's processing.
    It has completed working group last call and is in the hands of the IESG.

19. Will publication of this document change the status of any existing RFCs? If
    so, does the Datatracker metadata correctly reflect this and are those RFCs
    listed on the title page, in the abstract, and discussed in the
    introduction? If not, explain why and point to the part of the document
    where the relationship of this document to these other RFCs is discussed.
   
    No.

20. Describe the document shepherd's review of the IANA considerations section,
    especially with regard to its consistency with the body of the document.
    Confirm that all aspects of the document requiring IANA assignments are
    associated with the appropriate reservations in IANA registries. Confirm
    that any referenced IANA registries have been clearly identified. Confirm
    that each newly created IANA registry specifies its initial contents,
    allocations procedures, and a reasonable name (see [RFC 8126][11]).
   
    The IANA Considerations section is clear and complete.

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.

    Two new registries are created, and each will need a designated expert.
    It is reasonable to ask the authors of this document to serve in that role.
    Explanations and instructions are clear.

## Document History

1. Does the working group (WG) consensus represent the strong concurrence of a
  few individuals, with others being silent, or did it reach broad agreement?

  The document has broad agreement from the active working group.

2. Was there controversy about particular points, or were there decisions where
  the consensus was particularly rough?
 
  No.

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)?
 
  There are early implementations, though they are not listed.  The document is
  expected to get wide adoption.

## 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.
 
  There has been coordination with the SEDATE working group and its document
  draft-ietf-sedate-datetime-extended.  This document is ready to proceed, but
  there is still a normative reference to the SEDATE document.

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

7. If the document contains a YANG module, has the final version of the module
  been checked with any of the [recommended validation tools][4] for syntax and
  formatting validation? If there are any resulting errors or warnings, what is
  the justification for not fixing them at this time? Does the YANG module
  comply with the Network Management Datastore Architecture (NMDA) as specified
  in [RFC 8342][5]?
 
  N/A

8. Describe reviews and automated checks performed to validate sections of the
  final version of the document written in a formal language, such as XML code,
  BNF rules, MIB definitions, CBOR's CDDL, etc.
 
  As a product of the CBOR working group, the document has been reviewed by the
  CBOR experts.  There is some simple ABNF in it, which does not need expert
  review.

## Document Shepherd Checks

9. Based on the shepherd's review of the document, is it their opinion that this
  document is needed, clearly written, complete, correctly designed, and ready
  to be handed off to the responsible Area Director?
 
  Yes.

10. Several IETF Areas have assembled [lists of common issues that their
    reviewers encounter][6]. For which areas have such issues been identified
    and addressed? For which does this still need to happen in subsequent
    reviews?
   
    None identified.

11. What type of RFC publication is being requested on the IETF stream ([Best
    Current Practice][12], [Proposed Standard, Internet Standard][13],
    [Informational, Experimental or Historic][14])? Why is this the proper type
    of RFC? Do all Datatracker state attributes correctly reflect this intent?
   
    The document is aimed at Proposed Standard, providing standards-track guidance
    on CBOR time tags and an anchor for IANA registrations.  This is set in the
    datatracker after the working group decided to go for Standards Track (it was
    originally planned as Informational).

12. Have reasonable efforts been made to remind all authors of the intellectual
    property rights (IPR) disclosure obligations described in [BCP 79][7]? To
    the best of your knowledge, have all required disclosures been filed? If
    not, explain why. If yes, summarize any relevant discussion, including links
    to publicly-available messages when applicable.
   
    Yes.

13. Has each author, editor, and contributor shown their willingness to be
    listed as such? If the total number of authors and editors on the front page
    is greater than five, please provide a justification.
   
    Yes, and 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.)
   
    N/A

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?
   
    IEEE 1588-2008, "IEEE Standard for a Precision Clock Synchronization Protocol
    for Networked Measurement and Control Systems" requires payment or subscription.
    It is used in other IETF documents.
   
    JCGM 100:2008, "Evaluation of measurement data — Guide to the expression of
    uncertainty in measurement" is a product of the Joint Committee for Guides in
    Metrology.  It is freely available.

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?
   
    draft-ietf-sedate-datetime-extended is in the SEDATE working group's processing.
    It has completed working group last call and is in the hands of the IESG.

19. Will publication of this document change the status of any existing RFCs? If
    so, does the Datatracker metadata correctly reflect this and are those RFCs
    listed on the title page, in the abstract, and discussed in the
    introduction? If not, explain why and point to the part of the document
    where the relationship of this document to these other RFCs is discussed.
   
    No.

20. Describe the document shepherd's review of the IANA considerations section,
    especially with regard to its consistency with the body of the document.
    Confirm that all aspects of the document requiring IANA assignments are
    associated with the appropriate reservations in IANA registries. Confirm
    that any referenced IANA registries have been clearly identified. Confirm
    that each newly created IANA registry specifies its initial contents,
    allocations procedures, and a reasonable name (see [RFC 8126][11]).
   
    The IANA Considerations section is clear and complete.

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.

    Two new registries are created, and each will need a designated expert.
    It is reasonable to ask the authors of this document to serve in that role.
    Explanations and instructions are clear.

## Document History

1. Does the working group (WG) consensus represent the strong concurrence of a
  few individuals, with others being silent, or did it reach broad agreement?

  The document has broad agreement from the active working group.

2. Was there controversy about particular points, or were there decisions where
  the consensus was particularly rough?
 
  No.

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)?
 
  There are early implementations, though they are not listed.  The document is
  expected to get wide adoption.

## 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.
 
  There has been coordination with the SEDATE working group and its document
  draft-ietf-sedate-datetime-extended.  It would be good to explicitly note
  the last call on the SEDATE mailing list.

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.
 
  N/A

7. If the document contains a YANG module, has the final version of the module
  been checked with any of the [recommended validation tools][4] for syntax and
  formatting validation? If there are any resulting errors or warnings, what is
  the justification for not fixing them at this time? Does the YANG module
  comply with the Network Management Datastore Architecture (NMDA) as specified
  in [RFC 8342][5]?
 
  N/A

8. Describe reviews and automated checks performed to validate sections of the
  final version of the document written in a formal language, such as XML code,
  BNF rules, MIB definitions, CBOR's CDDL, etc.
 
  As a product of the CBOR working group, the document has been reviewed by the
  CBOR experts.  There is some simple ABNF in it, which does not need expert
  review.

## Document Shepherd Checks

9. Based on the shepherd's review of the document, is it their opinion that this
  document is needed, clearly written, complete, correctly designed, and ready
  to be handed off to the responsible Area Director?
 
  Yes.

10. Several IETF Areas have assembled [lists of common issues that their
    reviewers encounter][6]. For which areas have such issues been identified
    and addressed? For which does this still need to happen in subsequent
    reviews?
   
    None identified.

11. What type of RFC publication is being requested on the IETF stream ([Best
    Current Practice][12], [Proposed Standard, Internet Standard][13],
    [Informational, Experimental or Historic][14])? Why is this the proper type
    of RFC? Do all Datatracker state attributes correctly reflect this intent?
   
    The document is aimed at Informational, providing guidance on CBOR time tags
    and an anchor for IANA registrations.  This is set in the datatracker and the
    working group decided not to go for Standards Track on this.

12. Have reasonable efforts been made to remind all authors of the intellectual
    property rights (IPR) disclosure obligations described in [BCP 79][7]? To
    the best of your knowledge, have all required disclosures been filed? If
    not, explain why. If yes, summarize any relevant discussion, including links
    to publicly-available messages when applicable.
   
    Yes.

13. Has each author, editor, and contributor shown their willingness to be
    listed as such? If the total number of authors and editors on the front page
    is greater than five, please provide a justification.
   
    Yes, and 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.)
   
    N/A

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?
   
    IEEE 1588-2008, "IEEE Standard for a Precision Clock Synchronization Protocol
    for Networked Measurement and Control Systems" requires payment or subscription.
    It is used in other IETF documents.
   
    JCGM 100:2008, "Evaluation of measurement data — Guide to the expression of
    uncertainty in measurement" is a product of the Joint Committee for Guides in
    Metrology.  It is freely available.

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?
   
    draft-ietf-sedate-datetime-extended is in the SEDATE working group's processing.
    It has completed working group last call and is in the hands of the document
    shepherd.

19. Will publication of this document change the status of any existing RFCs? If
    so, does the Datatracker metadata correctly reflect this and are those RFCs
    listed on the title page, in the abstract, and discussed in the
    introduction? If not, explain why and point to the part of the document
    where the relationship of this document to these other RFCs is discussed.
   
    No.

20. Describe the document shepherd's review of the IANA considerations section,
    especially with regard to its consistency with the body of the document.
    Confirm that all aspects of the document requiring IANA assignments are
    associated with the appropriate reservations in IANA registries. Confirm
    that any referenced IANA registries have been clearly identified. Confirm
    that each newly created IANA registry specifies its initial contents,
    allocations procedures, and a reasonable name (see [RFC 8126][11]).
   
    The IANA Considerations section is clear and complete.

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.

    Two new registries are created, and each will need a designated expert.
    It is reasonable to ask the authors of this document to serve in that role.
    Explanations and instructions are clear.