IGP Flexible Algorithm in IP Networks
draft-ietf-lsr-ip-flexalgo-17

[Ballot comment]
Thanks for working on this specification.

I have no comment from TSV point of view. However, the description in section 3 is a not clear to me. It references 5G system and N3 interfaces then describes the need for UPF selection based on some sort of session needs. However, I could not relate how IP addresses plays role in that selection and where in 5G system this is done or planned to be done based of IP addresses? is there any deployment case or already deployed UPF selection based on just IP addresses?

If this section supposed to be the motivation of this whole specification then it need to be improved in description on how this specification helps in the usecase it describes. Or may be removed from the specification.

[Ballot comment]
Thank you for the work put into this document.

Special thanks to Acee Lindem for the shepherd's detailed write-up including the WG consensus *and* the justification of the intended status.

Other thanks to Antoine Fressancourt, the Internet directorate reviewer (at my request), please consider this int-dir review as if it was my own review:
https://datatracker.ietf.org/doc/review-ietf-lsr-ip-flexalgo-12-intdir-telechat-fressancourt-2023-06-01/ (and I have seen that the authors have responded to the review)

I hope that this review helps to improve the document,

Regards,

-éric

[Ballot comment]
NITS:

        A node MUST participate in a Flex-Algorithm to be:
        - Able to compute path for such Flex-Algorithm
        - Part of the topology for such Flex-Algorithm

This is an odd use of MUST.

Section 5.2 states the length of the Algorithm field, but not
of the Type: or Length: fields. (either do it for all or for none?)

Similar in Section 6.2 and 6.3.1

[Ballot comment]
Hi,

Thanks for this document.

Only one minor comment/question:

(1) p 4, sec 5.1.  The IS-IS IP Algorithm Sub-TLV                                                                                                                                                                                                           
                                                                                                                                                                                                                                                           
  The use of the IP Algorithm Sub-TLV to advertise support for                                                                                                                                                                                             
  algorithms outside the Flex-Algorithm range (128-255) is outside the                                                                                                                                                                                     
  scope of this document.                                                                                                                                                                                                                                 
                                                                                                                                                                                                                                                           
What does this actually mean if a router receives a SubTlV containing an algorithm outside the 128-255 range?  Should it ignore, or error? And should this be specified in this document?  I also note that this is stated here, under IS-IS, but there is no equivalent text for the OSPF definition, and hence wanted to ensure that is intentional.

Regards,
Rob

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

The IANA Functions Operator has completed its review of draft-ietf-lsr-ip-flexalgo-11. If any part of this review is inaccurate, please let us know.

The IANA Functions Operator has a question about one of the actions requested in the IANA Considerations section of this document.

The IANA Functions Operator understands that, upon approval of this document, there are nine actions which we must complete.

First, in the OSPF Router Information (RI) TLVs registry on the Open Shortest Path First (OSPF) Parameters registry page located at:

https://www.iana.org/assignments/ospf-parameters/

a single new registration will be made as follows:

Value: [ TBD-at-Registration ]
TLV Name: IP Algorithm TLV
Reference: [ RFC-to-be; Section 5.2 ]

Second, in the IS-IS Sub-TLVs for IS-IS Router CAPABILITY TLV registry on the IS-IS TLV Codepoints registry page located at:

https://www.iana.org/assignments/isis-tlv-codepoints/

the temporary registration for Value 29 will be made permanent and its reference changed to [ RFC-to-be ].

Value: 29
Description: IP Algorithm Sub-TLV
Reference: [ RFC-to-be; Section 5.1 ]

Third, in the IS-IS Top-Level TLV Codepoints registry also on the IS-IS TLV Codepoints registry page located at:

https://www.iana.org/assignments/isis-tlv-codepoints/

the two temporary registrations for Values 126 and 127 are to be made permanent and its reference changed to [ RFC-to-be ].

Value: 126
Description: IPv4 Algorithm Prefix Reachability TLV
Reference: [ RFC-to-be; Section 6.1 ]

Value: 127
Description: IPv6 Algorithm Prefix Reachability TLV
Reference: [ RFC-to-be; Section 6.2 ]

Fourth, in the IS-IS Sub-TLVs for TLVs Advertising Prefix Reachability registry also on the IS-IS TLV Codepoints registry page located at:

https://www.iana.org/assignments/isis-tlv-codepoints/

the description for the registry will be updated by adding "IPv4 Algorithm Prefix Reachability TLV (126)" and "IPv6 Algorithm Prefix Reachability TLV (127)" to the list of TLVs to the description of that registry.

Fifth, also in the IS-IS Sub-TLVs for TLVs Advertising Prefix Reachability registry also on the IS-IS TLV Codepoints registry page located at:

https://www.iana.org/assignments/isis-tlv-codepoints/

the registry will be changed so that columns marked "126" and "127" are added to each registration. The new columns for the existing registrations are as follows:

Type Description 126 127
---- ---------------------------------- --- ---
1 32-bit Administrative Tag Sub-TLV y y
2 64-bit Administrative Tag Sub-TLV y y
3 Prefix Segment Identifier n n
4 Prefix Attribute Flags y y
5 SRv6 End SID n n
6 Flex-Algorithm Prefix Metric n n
11 IPv4 Source Router ID y y
12 IPv6 Source Router ID y y
32 BIER Info n n

Sixth, in the OSPFv2 Extended Prefix TLV Sub-TLVs registry on the Open Shortest Path First (OSPF) v2 Parameters registry page located at:

https://www.iana.org/assignments/ospfv2-parameters/

two new registrations will be made as follows:

Value: [ TBD-at-Registration ]
TLV Name: OSPFv2 IP Algorithm Prefix Reachability Sub-TLV
Reverence: [ RFC-to-be; Section 6.3 ]

Value: [ TBD-at-Registration ]
TLV Name: OSPFv2 IP Forwarding Address Sub-TLV
Reverence: [ RFC-to-be; Section 6.3.1 ]

Seventh, a new registry is to be created called the IP Algorithm Prefix Reachability Sub-TLV Flags registry. The new registry is to be located on the Open Shortest Path First v2 (OSPFv2) Parameters registry page located at:

https://www.iana.org/assignments/ospfv2-parameters/

There is a single initial registration in the new registry as follows:

Bit Name Reference
0 Bit E [ RFC-to-be; Section 6.3 ]
1-7 [see below]

IANA Question --> Should bits 1-7 be marked "reserved" as indicated by Section 11 of the current draft or should they be marked "unassigned?"

The new registry is managed via IETF Review or IETF Approval as defined by RFC8126.

Eighth, in the OSPFv3 Extended-LSA Sub-TLVs registry on the Open Shortest Path First v3 (OSPFv3) Parameters registry located at:

https://www.iana.org/assignments/ospfv3-parameters/

two new registrations are to be made as follows:

Value: [ TBD-at-Registration ]
TLV Name: OSPFv3 IP Algorithm Prefix Reachability Sub-TLV
L2BM: [see below]
Reference: [ RFC-to-be; Section 6.4 ]

Value: [ TBD-at-Registration ]
TLV Name: OSPFv3 IP Flexible Algorithm ASBR Metric Sub-TLV
L2BM: [see below]
Reference: [ RFC-to-be; Section 6.5 ]

IANA Question --> What are the entries for the L2BM values for these new registrations in the OSPFv3 Extended-LSA Sub-TLVs registry?

Ninth, in the OSPFv2 Extended Inter-Area ASBR Sub-TLVs registry on the Open Shortest Path First v2 (OSPFv2) Parameters registry page located at:

https://www.iana.org/assignments/ospfv2-parameters/

a new registration is to be made as follows:

Value: [ TBD-at-Registration ]
Description: OSPF IP Flexible Algorithm ASBR Metric Sub-TLV
Reference: [ RFC-to-be; Section 6.5 ]

The IANA Functions Operator understands 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 Specialist

The following Last Call announcement was sent out (ends 2023-05-16):

From: The IESG
To: IETF-Announce
CC: acee.ietf@gmail.com, acee@cisco.com, draft-ietf-lsr-ip-flexalgo@ietf.org, jgs@juniper.net, lsr-chairs@ietf.org, lsr@ietf.org
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (IGP Flexible Algorithms (Flex-Algorithm) In IP Networks) to Proposed Standard


The IESG has received a request from the Link State Routing WG (lsr) to
consider the following document: - 'IGP Flexible Algorithms (Flex-Algorithm)
In IP Networks'
  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 2023-05-16. 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


  An IGP Flexible Algorithm (Flex-Algorithm) allows IGPs to compute
  constraint-based paths.  The base IGP Flex-Algorithm specification
  describes how it is used with Segment Routing (SR) data planes - SR
  MPLS and SRv6.

  This document extends IGP Flex-Algorithm, so that it can be used with
  regular IPv4 and IPv6 forwarding.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-lsr-ip-flexalgo/


The following IPR Declarations may be related to this I-D:

  https://datatracker.ietf.org/ipr/4317/
  https://datatracker.ietf.org/ipr/4519/

# Document Shepherd Writeup

*This version is dated 8 April 2023.*

Thank you for your service as a document shepherd. Among the responsibilities is
answering the questions in this writeup to give helpful context to Last Call and
Internet Engineering Steering Group ([IESG][1]) reviewers, and your diligence in
completing it, is appreciated. The full role of the shepherd is further
described in [RFC 4858][2], and informally. You will need the cooperation of
authors to complete these checks.

Note that some numbered items contain multiple related questions; please be sure
to answer all of them.

## 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?

  There was a broad consensus on WG adoption with a smaller number (6-12 non-authors)
  commenting and supporting publication. 

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

  We had a great discussion of the use cases and terminology and, as a result,
  there will be changes in the version submitted for publication. One individual
  WG member strongly suggested a solution that wouldn't interoperate with routers
  not supporting Flex Algo. However, it is not uncommon for this WG member to be
  in the minority.

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)?

  Cisco IOS-XR has an implementation that is shipping for IS-IS. Juniper
  has an implementation that has not yet shipped.


### Additional Reviews

5. Does this document need review from other IETF working groups or external
  organizations? Have those reviews occurred?

  No. A Routing Directorate review is in progress.

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.

  N/A.

### 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?

  It will be ready with the next revision.

10. Several IETF Areas have assembled [lists of common issues that their
    reviewers encounter][6]. Do any such issues remain that would merit specific
    attention from subsequent reviews?

    No.

11. What type of RFC publication is being requested on the IETF stream (Best
    Current Practice, Proposed Standard, Internet Standard, Informational,
    Experimental, or Historic)? Why is this the proper type of RFC? Do all
    Datatracker state attributes correctly reflect this intent?

    Proposed standard. This level is required for protocol interoperability.

12. Has the interested community confirmed that any and all appropriate IPR
    disclosures required by [BCP 78][7] and [BCP 79][8] have been filed? If not,
    explain why. If yes, summarize any discussion and conclusion regarding the
    intellectual property rights (IPR) disclosures, including links to relevant
    emails.

    Yes.

13. Has each Author or Contributor confirmed their willingness to be listed as
    such? If the number of Authors/Editors on the front page is greater than 5,
    please provide a justification.

    There are six authors and all have contributed to the document and will be
    engaged during the review and publication process. While the IETF discussion
    mainly involved Ron, Shraddha, and Peter, LSR list discussions, William,
    Parag, and Rajesh were responsible for the initial encodings and prototyping
    through multiple iterations.

14. Identify any remaining I-D nits in this document. (See [the idnits tool][9]
    and the checkbox items found in Guidelines to Authors of Internet-Drafts).
    Simply running the idnits tool is not enough; please review the entire
    guidelines document.

15. Should any informative references be normative or vice-versa?

  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?

  ISO Spec?

17. Are there any normative downward references (see [RFC 3967][10],
    [BCP 97][11])? If so, list them.

    No.

18. Are there normative references to documents that are not ready for
    advancement or are otherwise in an unclear state? If they exist, what is the
    plan for their completion?

    No. The base flex algo document has already been submitted for publication.

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][12]).

    The IANA allocations have been reviewed and allocated through the
    early allocation process.

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.

    N/A - only additions to existing IANA registries.

# Document Shepherd Writeup

*This version is dated 8 April 2023.*

Thank you for your service as a document shepherd. Among the responsibilities is
answering the questions in this writeup to give helpful context to Last Call and
Internet Engineering Steering Group ([IESG][1]) reviewers, and your diligence in
completing it, is appreciated. The full role of the shepherd is further
described in [RFC 4858][2], and informally. You will need the cooperation of
authors to complete these checks.

Note that some numbered items contain multiple related questions; please be sure
to answer all of them.

## 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?

  There was a broad consensus on WG adoption with a smaller number (6-12 non-authors)
  commenting and supporting publication. 

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

  We had a great discussion of the use cases and terminology and, as a result,
  there will be changes in the version submitted for publication. One individual
  WG member strongly suggested a solution that wouldn't interoperate with routers
  not supporting Flex Algo. However, it is not uncommon for this WG member to be
  in the minority.

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)?

  Cisco IOS-XR has an implementation that is shipping for IS-IS. Juniper
  has an implementation that has not yet shipped.


### Additional Reviews

5. Does this document need review from other IETF working groups or external
  organizations? Have those reviews occurred?

  No. A Routing Directorate review is in progress.

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.

  N/A.

### 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?

  It will be ready with the next revision.

10. Several IETF Areas have assembled [lists of common issues that their
    reviewers encounter][6]. Do any such issues remain that would merit specific
    attention from subsequent reviews?

    No.

11. What type of RFC publication is being requested on the IETF stream (Best
    Current Practice, Proposed Standard, Internet Standard, Informational,
    Experimental, or Historic)? Why is this the proper type of RFC? Do all
    Datatracker state attributes correctly reflect this intent?

    Proposed standard. This level is required for protocol interoperability.

12. Has the interested community confirmed that any and all appropriate IPR
    disclosures required by [BCP 78][7] and [BCP 79][8] have been filed? If not,
    explain why. If yes, summarize any discussion and conclusion regarding the
    intellectual property rights (IPR) disclosures, including links to relevant
    emails.

    Yes.

13. Has each Author or Contributor confirmed their willingness to be listed as
    such? If the number of Authors/Editors on the front page is greater than 5,
    please provide a justification.

    There are six authors and all have contributed to the document and will be
    engaged during the review and publication process. While the IETF discussion
    mainly involved Ron, Shraddha, and Peter, LSR list discussions, William,
    Parag, and Rajesh were responsible for the initial encodings and prototyping
    through multiple iterations.

14. Identify any remaining I-D nits in this document. (See [the idnits tool][9]
    and the checkbox items found in Guidelines to Authors of Internet-Drafts).
    Simply running the idnits tool is not enough; please review the entire
    guidelines document.

15. Should any informative references be normative or vice-versa?

  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?

  ISO Spec?

17. Are there any normative downward references (see [RFC 3967][10],
    [BCP 97][11])? If so, list them.

    No.

18. Are there normative references to documents that are not ready for
    advancement or are otherwise in an unclear state? If they exist, what is the
    plan for their completion?

    No. The base flex algo document has already been submitted for publication.

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][12]).

    The IANA allocations have been reviewed and allocated through the
    early allocation process.

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.

    N/A - only additions to existing IANA registries.

# Document Shepherd Writeup

*This version is dated 8 April 2023.*

Thank you for your service as a document shepherd. Among the responsibilities is
answering the questions in this writeup to give helpful context to Last Call and
Internet Engineering Steering Group ([IESG][1]) reviewers, and your diligence in
completing it, is appreciated. The full role of the shepherd is further
described in [RFC 4858][2], and informally. You will need the cooperation of
authors to complete these checks.

Note that some numbered items contain multiple related questions; please be sure
to answer all of them.

## 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?

  There was a broad consensus on WG adoption with a smaller number (6-12 non-authors)
  commenting and supporting publication. 

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

  We had a great discussion of the use cases and terminology and, as a result,
  there will be changes in the version submitted for publication. One individual
  WG memember strongly suggested a solution that wouldn't interoperate with routers
  not supporting Flex Algo. However, it is not uncommon for this WG member to be
  in the minority.

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)?

  Cisco IOS-XR has an implementation that is shipping for IS-IS. Juniper
  has an implementation that has not yet shipped.


### Additional Reviews

5. Does this document need review from other IETF working groups or external
  organizations? Have those reviews occurred?

  No. A Routing Directorate review is in progress.

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.

  N/A.

### 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?

  It will be ready with the next revision.

10. Several IETF Areas have assembled [lists of common issues that their
    reviewers encounter][6]. Do any such issues remain that would merit specific
    attention from subsequent reviews?

    No.

11. What type of RFC publication is being requested on the IETF stream (Best
    Current Practice, Proposed Standard, Internet Standard, Informational,
    Experimental, or Historic)? Why is this the proper type of RFC? Do all
    Datatracker state attributes correctly reflect this intent?

    Proposed standard. This level is required for protocol interoperability.

12. Has the interested community confirmed that any and all appropriate IPR
    disclosures required by [BCP 78][7] and [BCP 79][8] have been filed? If not,
    explain why. If yes, summarize any discussion and conclusion regarding the
    intellectual property rights (IPR) disclosures, including links to relevant
    emails.

    Yes.

13. Has each Author or Contributor confirmed their willingness to be listed as
    such? If the number of Authors/Editors on the front page is greater than 5,
    please provide a justification.

    There are six authors and all have contributed to the document and will be
    engaged during the review and publication process. While the IETF discussion
    mainly involved Ron, Shraddha, and Peter, LSR list discussions, William,
    Parag, and Rajesh were responsible for the initial encodings and prototyping
    through multiple iterations.

14. Identify any remaining I-D nits in this document. (See [the idnits tool][9]
    and the checkbox items found in Guidelines to Authors of Internet-Drafts).
    Simply running the idnits tool is not enough; please review the entire
    guidelines document.

15. Should any informative references be normative or vice-versa?

  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?

  ISO Spec?

17. Are there any normative downward references (see [RFC 3967][10],
    [BCP 97][11])? If so, list them.

    No.

18. Are there normative references to documents that are not ready for
    advancement or are otherwise in an unclear state? If they exist, what is the
    plan for their completion?

    No. The base flex algo document has already been submitted for publication.

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][12]).

    The IANA allocations have been reviewed and allocated through the
    early allocation process.

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.

    N/A - only additions to existing IANA registries.

# Document Shepherd Writeup

*This version is dated 8 April 2023.*

Thank you for your service as a document shepherd. Among the responsibilities is
answering the questions in this writeup to give helpful context to Last Call and
Internet Engineering Steering Group ([IESG][1]) reviewers, and your diligence in
completing it, is appreciated. The full role of the shepherd is further
described in [RFC 4858][2], and informally. You will need the cooperation of
authors to complete these checks.

Note that some numbered items contain multiple related questions; please be sure
to answer all of them.

## 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?

  There was a broad consensus on WG adoption with a smaller number (6-12 non-authors)
  commenting and supporting publication. 

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

  We had a great discussion of the use cases and terminology and, as a result,
  there will be changes in the version submitted for publication. One individual
  WG memember strongly suggested a solution that wouldn't interoperate with routers
  not supporting Flex Algo. However, it is not uncommon for this WG member to be
  in the minority.

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)?

  Cisco IOS-XR has an implementation that is shipping for IS-IS. Juniper
  has an implementation that has not yet shipped.


### Additional Reviews

5. Does this document need review from other IETF working groups or external
  organizations? Have those reviews occurred?

  No. A Routing Directorate review is in progress.

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.

  N/A.

### 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?

  It will be ready with the next revision.

10. Several IETF Areas have assembled [lists of common issues that their
    reviewers encounter][6]. Do any such issues remain that would merit specific
    attention from subsequent reviews?

    No.

11. What type of RFC publication is being requested on the IETF stream (Best
    Current Practice, Proposed Standard, Internet Standard, Informational,
    Experimental, or Historic)? Why is this the proper type of RFC? Do all
    Datatracker state attributes correctly reflect this intent?

    Proposed standard. This level is required for protocol interoperability.

12. Has the interested community confirmed that any and all appropriate IPR
    disclosures required by [BCP 78][7] and [BCP 79][8] have been filed? If not,
    explain why. If yes, summarize any discussion and conclusion regarding the
    intellectual property rights (IPR) disclosures, including links to relevant
    emails.

    Yes.

13. Has each Author or Contributor confirmed their willingness to be listed as
    such? If the number of Authors/Editors on the front page is greater than 5,
    please provide a justification.

    There are six authors and all have contributed to the document and will be
    engaged during the review and publication process. While the IETF discussion
    mainly involved Ron, Shraddha, and Peter have been primarily involved during
    LSR list discussions, William, Parag, and Rajesh were responsible for the
    initial encodings, prototyping, and iteration.

14. Identify any remaining I-D nits in this document. (See [the idnits tool][9]
    and the checkbox items found in Guidelines to Authors of Internet-Drafts).
    Simply running the idnits tool is not enough; please review the entire
    guidelines document.

15. Should any informative references be normative or vice-versa?

  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?

  ISO Spec?

17. Are there any normative downward references (see [RFC 3967][10],
    [BCP 97][11])? If so, list them.

    No.

18. Are there normative references to documents that are not ready for
    advancement or are otherwise in an unclear state? If they exist, what is the
    plan for their completion?

    No. The base flex algo document has already been submitted for publication.

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][12]).

    The IANA allocations have been reviewed and allocated through the
    early allocation process.

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.

    N/A - only additions to existing IANA registries.

# Document Shepherd Writeup

*This version is dated 8 April 2023.*

Thank you for your service as a document shepherd. Among the responsibilities is
answering the questions in this writeup to give helpful context to Last Call and
Internet Engineering Steering Group ([IESG][1]) reviewers, and your diligence in
completing it, is appreciated. The full role of the shepherd is further
described in [RFC 4858][2], and informally. You will need the cooperation of
authors to complete these checks.

Note that some numbered items contain multiple related questions; please be sure
to answer all of them.

## 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?

  There was a broad consensus on WG adoption with a smaller number (6-12 non-authors)
  commenting and supporting publication. 

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

  We had a great discussion of the use cases and terminology and, as a result,
  there will be changes in the version submitted for publication. One individual
  WG memember strongly suggested a solution that wouldn't interoperate with routers
  not supporting Flex Algo. However, it is not uncommon for this WG member to be
  in the minority.

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)?

  Cisco IOS-XR has an implementation that is shipping for IS-IS. Juniper
  has an implementation that has not yet shipped.


### Additional Reviews

5. Does this document need review from other IETF working groups or external
  organizations? Have those reviews occurred?

  No. A Routing Directorate review is in progress.

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.

  N/A.

### 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?

  It will be ready with the next revision.

10. Several IETF Areas have assembled [lists of common issues that their
    reviewers encounter][6]. Do any such issues remain that would merit specific
    attention from subsequent reviews?

    No.

11. What type of RFC publication is being requested on the IETF stream (Best
    Current Practice, Proposed Standard, Internet Standard, Informational,
    Experimental, or Historic)? Why is this the proper type of RFC? Do all
    Datatracker state attributes correctly reflect this intent?

    Proposed standard. This level is required for protocol interoperability.

12. Has the interested community confirmed that any and all appropriate IPR
    disclosures required by [BCP 78][7] and [BCP 79][8] have been filed? If not,
    explain why. If yes, summarize any discussion and conclusion regarding the
    intellectual property rights (IPR) disclosures, including links to relevant
    emails.

    Yes.

13. Has each Author or Contributor confirmed their willingness to be listed as
    such? If the number of Authors/Editors on the front page is greater than 5,
    please provide a justification.

    Yes - discussion of six authors in progress.

14. Identify any remaining I-D nits in this document. (See [the idnits tool][9]
    and the checkbox items found in Guidelines to Authors of Internet-Drafts).
    Simply running the idnits tool is not enough; please review the entire
    guidelines document.

15. Should any informative references be normative or vice-versa?

  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?

  ISO Spec?

17. Are there any normative downward references (see [RFC 3967][10],
    [BCP 97][11])? If so, list them.

    No.

18. Are there normative references to documents that are not ready for
    advancement or are otherwise in an unclear state? If they exist, what is the
    plan for their completion?

    No. The base flex algo document has already been submitted for publication.

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][12]).

    The IANA allocations have been reviewed and allocated through the
    early allocation process.

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.

    N/A - only additions to existing IANA registries.

# Document Shepherd Writeup

*This version is dated 8 April 2023.*

Thank you for your service as a document shepherd. Among the responsibilities is
answering the questions in this writeup to give helpful context to Last Call and
Internet Engineering Steering Group ([IESG][1]) reviewers, and your diligence in
completing it, is appreciated. The full role of the shepherd is further
described in [RFC 4858][2], and informally. You will need the cooperation of
authors to complete these checks.

Note that some numbered items contain multiple related questions; please be sure
to answer all of them.

## 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?

  There was a broad consensus on WG adoption with a smaller number (6-12 non-authors)
  commenting and supporting publication. 

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

  We had a great discussion of the use cases and terminology and, as a result,
  there will be changes in the version submitted for publication. One individual
  WG memember strongly suggested a solution that wouldn't interoperate with routers
  not supporting Flex Algo. However, it is not uncommon for this WG member to be
  in the minority.

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)?

  Cisco IOS-XR has an implementation that is shipping for IS-IS. 

### Additional Reviews

5. Does this document need review from other IETF working groups or external
  organizations? Have those reviews occurred?

  No. A Routing Directorate review is in progress.

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.

  N/A.

### 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?

  It will be ready with the next revision.

10. Several IETF Areas have assembled [lists of common issues that their
    reviewers encounter][6]. Do any such issues remain that would merit specific
    attention from subsequent reviews?

    No.

11. What type of RFC publication is being requested on the IETF stream (Best
    Current Practice, Proposed Standard, Internet Standard, Informational,
    Experimental, or Historic)? Why is this the proper type of RFC? Do all
    Datatracker state attributes correctly reflect this intent?

    Proposed standard. This level is required for protocol interoperability.

12. Has the interested community confirmed that any and all appropriate IPR
    disclosures required by [BCP 78][7] and [BCP 79][8] have been filed? If not,
    explain why. If yes, summarize any discussion and conclusion regarding the
    intellectual property rights (IPR) disclosures, including links to relevant
    emails.

    Yes.

13. Has each Author or Contributor confirmed their willingness to be listed as
    such? If the number of Authors/Editors on the front page is greater than 5,
    please provide a justification.

    Yes - discussion of six authors in progress.

14. Identify any remaining I-D nits in this document. (See [the idnits tool][9]
    and the checkbox items found in Guidelines to Authors of Internet-Drafts).
    Simply running the idnits tool is not enough; please review the entire
    guidelines document.

15. Should any informative references be normative or vice-versa?

  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?

  ISO Spec?

17. Are there any normative downward references (see [RFC 3967][10],
    [BCP 97][11])? If so, list them.

    No.

18. Are there normative references to documents that are not ready for
    advancement or are otherwise in an unclear state? If they exist, what is the
    plan for their completion?

    No. The base flex algo document has already been submitted for publication.

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][12]).

    The IANA allocations have been reviewed and allocated through the
    early allocation process.

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.

    N/A - only additions to existing IANA registries.

# Document Shepherd Writeup

*This version is dated 8 April 2023.*

Thank you for your service as a document shepherd. Among the responsibilities is
answering the questions in this writeup to give helpful context to Last Call and
Internet Engineering Steering Group ([IESG][1]) reviewers, and your diligence in
completing it, is appreciated. The full role of the shepherd is further
described in [RFC 4858][2], and informally. You will need the cooperation of
authors to complete these checks.

Note that some numbered items contain multiple related questions; please be sure
to answer all of them.

## 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?

  There was a broad consensus on WG adoption with a smaller number (6-12 non-authors)
  commenting and supporting publication. 

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

  We had a great discussion of the use cases and terminology and, as a result,
  there will be changes in the version submitted for publication.


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 plans to implement but none generally available. 

### Additional Reviews

5. Does this document need review from other IETF working groups or external
  organizations? Have those reviews occurred?

  No. A Routing Directorate review is in progress.

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.

  N/A.

### 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?

  It will be ready with the next revision.

10. Several IETF Areas have assembled [lists of common issues that their
    reviewers encounter][6]. Do any such issues remain that would merit specific
    attention from subsequent reviews?

    No.

11. What type of RFC publication is being requested on the IETF stream (Best
    Current Practice, Proposed Standard, Internet Standard, Informational,
    Experimental, or Historic)? Why is this the proper type of RFC? Do all
    Datatracker state attributes correctly reflect this intent?

    Proposed standard. This level is required for protocol interoperability.

12. Has the interested community confirmed that any and all appropriate IPR
    disclosures required by [BCP 78][7] and [BCP 79][8] have been filed? If not,
    explain why. If yes, summarize any discussion and conclusion regarding the
    intellectual property rights (IPR) disclosures, including links to relevant
    emails.

    Yes.

13. Has each Author or Contributor confirmed their willingness to be listed as
    such? If the number of Authors/Editors on the front page is greater than 5,
    please provide a justification.

    Yes - discussion of six authors in progress.

14. Identify any remaining I-D nits in this document. (See [the idnits tool][9]
    and the checkbox items found in Guidelines to Authors of Internet-Drafts).
    Simply running the idnits tool is not enough; please review the entire
    guidelines document.

15. Should any informative references be normative or vice-versa?

  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?

  ISO Spec?

17. Are there any normative downward references (see [RFC 3967][10],
    [BCP 97][11])? If so, list them.

    No.

18. Are there normative references to documents that are not ready for
    advancement or are otherwise in an unclear state? If they exist, what is the
    plan for their completion?

    No. The base flex algo document has already been submitted for publication.

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][12]).

    The IANA allocations have been reviewed and allocated through the
    early allocation process.

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.

    N/A - only additions to existing IANA registries.

# Document Shepherd Writeup

*This version is dated 8 April 2023.*

Thank you for your service as a document shepherd. Among the responsibilities is
answering the questions in this writeup to give helpful context to Last Call and
Internet Engineering Steering Group ([IESG][1]) reviewers, and your diligence in
completing it, is appreciated. The full role of the shepherd is further
described in [RFC 4858][2], and informally. You will need the cooperation of
authors to complete these checks.

Note that some numbered items contain multiple related questions; please be sure
to answer all of them.

## 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?

  There was a broad consensus on WG adoption with a smaller number (6-12 non-authors)
  commenting and supporting publication. 

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

  We had a great discussion of the use cases and terminology and, as a result,
  there will be changes in the version submitted for publication.


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 plans to implement but none generally available. 

### Additional Reviews

5. Does this document need review from other IETF working groups or external
  organizations? Have those reviews occurred?

  No. A Routing Directorate review is in progress.

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.

  N/A.

### 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?

  It will be ready with the next revision.

10. Several IETF Areas have assembled [lists of common issues that their
    reviewers encounter][6]. Do any such issues remain that would merit specific
    attention from subsequent reviews?

    No.

11. What type of RFC publication is being requested on the IETF stream (Best
    Current Practice, Proposed Standard, Internet Standard, Informational,
    Experimental, or Historic)? Why is this the proper type of RFC? Do all
    Datatracker state attributes correctly reflect this intent?

    Proposed standard. This level is required for protocol interoperability.

12. Has the interested community confirmed that any and all appropriate IPR
    disclosures required by [BCP 78][7] and [BCP 79][8] have been filed? If not,
    explain why. If yes, summarize any discussion and conclusion regarding the
    intellectual property rights (IPR) disclosures, including links to relevant
    emails.

    Yes.

13. Has each Author or Contributor confirmed their willingness to be listed as
    such? If the number of Authors/Editors on the front page is greater than 5,
    please provide a justification.

    Yes - discussion of six authors in progress.

14. Identify any remaining I-D nits in this document. (See [the idnits tool][9]
    and the checkbox items found in Guidelines to Authors of Internet-Drafts).
    Simply running the idnits tool is not enough; please review the entire
    guidelines document.

15. Should any informative references be normative or vice-versa?

  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?

  ISO Spec?

17. Are there any normative downward references (see [RFC 3967][10],
    [BCP 97][11])? If so, list them.

    No.

18. Are there normative references to documents that are not ready for
    advancement or are otherwise in an unclear state? If they exist, what is the
    plan for their completion?

    No. The base flex algo document has already been submitted for publication.

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][12]).

    The IANA allocations have been reviewed and allocated through the
    early allocation process.

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.

    N/A - only additions to existing IANA registries.