Use Cases for a PCE as a Central Controller (PCECC)
draft-ietf-teas-pcecc-use-cases-18

Received changes through RFC Editor sync (changed state to RFC, created became rfc relationship between draft-ietf-teas-pcecc-use-cases and RFC 9689, changed IESG state to RFC Published)

[Ballot comment]
Thank you to Susan Hares for the GENART review:

** As pointed out by the GENART review, consider not referencing the solutions of unadopted drafts.  They aren’t needed to describe the use case.  Specifically:

  [I-D.chen-pce-bier]
  [I-D.chen-pce-pcep-extension-pce-controller-bier]
  [I-D.cbrt-pce-stateful-local-protection]
  [I-D.chen-pce-bier]
  [I-D.chen-pce-pcep-extension-pce-controller-bier]
  [I-D.dhody-pce-pcep-extension-pce-controller-srv6]
  [I-D.li-pce-controlled-id-space]

** Section A.4
  There is research [MAP-REDUCE] that show how usage of the multicast
  tree could improve the speed of resource or cluster members'
  discovery inside the cluster as well as increase redundancy in
  communications between cluster nodes.

  Is traditional IP-based multicast enough for that?  We doubt it
  because it requires an additional control plane (IGMP, PIM) and a lot
  of signalling, that is not suitable for high-performance
  computations, that are very sensitive to latency.

What does “we doubt it” mean?  Should this be framed more definitively?

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

IANA has completed its review of draft-ietf-teas-pcecc-use-cases-14, which is currently in Last Call, and has the following comments:

We understand that this document doesn't require any registry actions.

While it's often helpful for a document's IANA Considerations section to remain in place upon publication even if there are no actions, if the authors strongly prefer to remove it, we do not object.

If this assessment is not accurate, please respond as soon as possible.

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 2024-05-20):

From: The IESG
To: IETF-Announce
CC: draft-ietf-teas-pcecc-use-cases@ietf.org, james.n.guichard@futurewei.com, teas-chairs@ietf.org, teas@ietf.org, vishnupavan@gmail.com
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (Use Cases for PCE as a Central Controller (PCECC).) to Informational RFC


The IESG has received a request from the Traffic Engineering Architecture and
Signaling WG (teas) to consider the following document: - 'Use Cases for PCE
as a Central Controller (PCECC).'
  as Informational RFC

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 2024-05-20. 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 PCE is a core component of a Software-Defined Networking (SDN)
  system.  It can be used to compute optimal paths for network traffic
  and update existing paths to reflect changes in the network or
  traffic demands.  PCE was developed to derive traffic-engineered
  paths in MPLS networks, which are supplied to the head end of the
  paths using the Path Computation Element Communication Protocol
  (PCEP).

  SDN has a much broader applicability than signal MPLS traffic-
  engineered (TE) paths and the PCE may be used to determine paths in a
  range of use cases including static Label Switched Paths (LSPs),
  Segment Routing (SR), Service Function Chaining (SFC), and most forms
  of a routed or switched network.  It is, therefore, reasonable to
  consider PCEP as a control protocol for use in these environments to
  allow the PCE to be fully enabled as a central controller.

  A PCE as a Central Controller (PCECC) can simplify the processing of
  a distributed control plane by blending it with elements of SDN and
  without necessarily completely replacing it.  This document describes
  general considerations for PCECC deployment and examines its
  applicability and benefits, as well as its challenges and
  limitations, through a number of use cases.  PCEP extensions which
  are required for the PCECC use cases are covered in separate
  documents.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-teas-pcecc-use-cases/


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

  https://datatracker.ietf.org/ipr/2940/
  https://datatracker.ietf.org/ipr/5573/

# Document Shepherd Write-Up for Group Documents

*This version is dated 4 July 2022.*

Thank you for your service as a document shepherd. Among the responsibilities is
answering the questions in this write-up 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]. You will need the cooperation of the authors
and editors 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?

“Strong concurrence of a few individuals, with others being silent" is a reasonable
characterization.

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

There was no controversy. There were no decisions where the consensus was
particularly rough.

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 one has threatened an appeal. No one has indicated extreme discontent.

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)?

This document does not propose any protocol extensions. It is an informational
Document that describes general considerations for deployment of Path Computation
Element as a Central Controller (PCECC). The document examines PCECC's
applicability and benefits, as well as its challenges and limitations, through a
number of use cases. There are no existing implementations of PCECC
reported in the document. The PCEP extensions which may be required for the
PCECC use cases are covered in separate documents.

## 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.

This document is relevant to the protocol work being done in the PCE WG. The PCE
WG was notified about the Last Call in TEAS. Please refer to -
https://mailarchive.ietf.org/arch/msg/pce/Hsp2thK4KU_5_56G3m_az7Z7CrA/

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

The document has been reviewed by the Routing Directorate. Please refer to -
https://mailarchive.ietf.org/arch/msg/teas/MTwqNSnboAzOW7HP72Ad1WQMMKw/

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]?

The document does not contain a YANG module.

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.

There is no section in the document that is written in a formal language, such as
XML code, BNF rules, MIB definitions, CBOS's CDDL, etc.

## 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, it is the shepherd's opinion that the document is needed, reasonably well
written, complete and ready to be handed off to the responsible Area Director.

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?

It is the shepherd's opinion that the document sufficiently addresses all
the issues specified in [6].

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 type of publication being requested is "Informational". This is appropriate
because this document describes the various use cases for the PCECC architecture.
All Datatracker state attributes correctly reflect this intent.

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.

The TEAS WG conducts an IPR poll before an individual draft becomes a WG document
and before a WG document goes to last call. The WG process requires IPR compliance
statement from all authors and contributors listed in the document. This process
was duly applied to the document. There is an IPR disclosure associated with this
document -
https://datatracker.ietf.org/ipr/search/?submit=draft&id=draft-ietf-teas-pcecc-use-cases

Pre-WGLC IPR Poll: Please refer to entries dated 2022-05-17, 2022-05-24
and 2022-06-14 at
https://datatracker.ietf.org/doc/draft-ietf-teas-pcecc-use-cases/history/

Pre-WG-Adoption IPR Poll: Please refer to the thread -
https://mailarchive.ietf.org/arch/msg/teas/oy5wSW2WPhUXPCe834TiAyaGo8Y/


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.

The authors/editors and contributors have had sufficient opportunities to express
unwillingness to be listed as such. There are 5 authors listed on the front page
and 5 other contributors listed later in the document.

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.)

There are no I-D nits that are yet to be resolved.

15. Should any informative references be normative or vice-versa? See the [IESG
    Statement on Normative and Informative References][16].

All listed informative and normative references are appropriate.

16. List any normative references that are not freely available to anyone. Did
    the community have sufficient access to review any such normative
    references?

All listed normative references that are 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.

There are no normative downward references. All listed normative references
are published RFCs.

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?

All listed normative references are published RFCs.

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.

The publication of this document will not change the status of any existing RFCs.

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]).

This draft makes no requests for IANA action.

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.

This draft makes no requests for IANA action.

[1]: https://www.ietf.org/about/groups/iesg/
[2]: https://www.rfc-editor.org/rfc/rfc4858.html
[3]: https://www.rfc-editor.org/rfc/rfc7942.html
[4]: https://trac.ietf.org/trac/ops/wiki/yang-review-tools
[5]: https://www.rfc-editor.org/rfc/rfc8342.html
[6]: https://trac.ietf.org/trac/iesg/wiki/ExpertTopics
[7]: https://www.rfc-editor.org/info/bcp79
[8]: https://www.ietf.org/tools/idnits/
[9]: https://www.rfc-editor.org/rfc/rfc3967.html
[10]: https://www.rfc-editor.org/info/bcp97
[11]: https://www.rfc-editor.org/rfc/rfc8126.html
[12]: https://www.rfc-editor.org/rfc/rfc2026.html#section-5
[13]: https://www.rfc-editor.org/rfc/rfc2026.html#section-4.1
[14]: https://www.rfc-editor.org/rfc/rfc2026.html#section-4.2
[15]: https://authors.ietf.org/en/content-guidelines-overview
[16]: https://www.ietf.org/about/groups/iesg/statements/normative-informative-references/
[17]: https://datatracker.ietf.org/doc/downref/

# Document Shepherd Write-Up for Group Documents

*This version is dated 4 July 2022.*

Thank you for your service as a document shepherd. Among the responsibilities is
answering the questions in this write-up 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]. You will need the cooperation of the authors
and editors 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?

“Strong concurrence of a few individuals, with others being silent" is a reasonable
characterization.

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

There was no controversy. There were no decisions where the consensus was
particularly rough.

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 one has threatened an appeal. No one has indicated extreme discontent.

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)?

This document does not propose any protocol extensions. It is an informational
Document that describes general considerations for deployment of Path Computation
Element as a Central Controller (PCECC). The document examines PCECC's
applicability and benefits, as well as its challenges and limitations, through a
number of use cases. There are no existing implementations of PCECC
reported in the document. The PCEP extensions which may be required for the
PCECC use cases are covered in separate documents.

## 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.

This document is relevant to the protocol work being done in the PCE WG. The PCE
WG was notified about the Last Call in TEAS. Please refer to -
https://mailarchive.ietf.org/arch/msg/pce/Hsp2thK4KU_5_56G3m_az7Z7CrA/

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

The document has been reviewed by the Routing Directorate. Please refer to -
https://mailarchive.ietf.org/arch/msg/teas/MTwqNSnboAzOW7HP72Ad1WQMMKw/

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]?

The document does not contain a YANG module.

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.

There is no section in the document that is written in a formal language, such as
XML code, BNF rules, MIB definitions, CBOS's CDDL, etc.

## 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, it is the shepherd's opinion that the document is needed, reasonably well
written, complete and ready to be handed off to the responsible Area Director.

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?

It is the shepherd's opinion that the document sufficiently addresses all
the issues specified in [6].

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 type of publication being requested is "Informational". This is appropriate
because this document describes the various use cases for the PCECC architecture.
All Datatracker state attributes correctly reflect this intent.

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.

The TEAS WG conducts an IPR poll before an individual draft becomes a WG document
and before a WG document goes to last call. The WG process requires IPR compliance
statement from all authors and contributors listed in the document. This process
was duly applied to the document. There is an IPR disclosure associated with this
document -
https://datatracker.ietf.org/ipr/search/?submit=draft&id=draft-ietf-teas-pcecc-use-cases

Pre-WGLC IPR Poll: Please refer to entries dated 2022-05-17, 2022-05-24
and 2022-06-14 at
https://datatracker.ietf.org/doc/draft-ietf-teas-pcecc-use-cases/history/

Pre-WG-Adoption IPR Poll: Please refer to the thread -
https://mailarchive.ietf.org/arch/msg/teas/oy5wSW2WPhUXPCe834TiAyaGo8Y/


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.

The authors/editors and contributors have had sufficient opportunities to express
unwillingness to be listed as such. There are 5 authors listed on the front page
and 5 other contributors listed later in the document.

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.)

There are no I-D nits that are yet to be resolved.

15. Should any informative references be normative or vice-versa? See the [IESG
    Statement on Normative and Informative References][16].

All listed informative and normative references are appropriate.

16. List any normative references that are not freely available to anyone. Did
    the community have sufficient access to review any such normative
    references?

All listed normative references that are 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.

There are no normative downward references. All listed normative references
are published RFCs.

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?

All listed normative references are published RFCs.

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.

The publication of this document will not change the status of any existing RFCs.

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]).

This draft makes no requests for IANA action.

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.

This draft makes no requests for IANA action.

[1]: https://www.ietf.org/about/groups/iesg/
[2]: https://www.rfc-editor.org/rfc/rfc4858.html
[3]: https://www.rfc-editor.org/rfc/rfc7942.html
[4]: https://trac.ietf.org/trac/ops/wiki/yang-review-tools
[5]: https://www.rfc-editor.org/rfc/rfc8342.html
[6]: https://trac.ietf.org/trac/iesg/wiki/ExpertTopics
[7]: https://www.rfc-editor.org/info/bcp79
[8]: https://www.ietf.org/tools/idnits/
[9]: https://www.rfc-editor.org/rfc/rfc3967.html
[10]: https://www.rfc-editor.org/info/bcp97
[11]: https://www.rfc-editor.org/rfc/rfc8126.html
[12]: https://www.rfc-editor.org/rfc/rfc2026.html#section-5
[13]: https://www.rfc-editor.org/rfc/rfc2026.html#section-4.1
[14]: https://www.rfc-editor.org/rfc/rfc2026.html#section-4.2
[15]: https://authors.ietf.org/en/content-guidelines-overview
[16]: https://www.ietf.org/about/groups/iesg/statements/normative-informative-references/
[17]: https://datatracker.ietf.org/doc/downref/

As per the guidance given by Routing Area ADs, we now require early directorate reviews before documents enter the publication queue. The document will be submitted to IESG for Publication after this review is complete.

Pre WG LC IPR Poll Responses:

Lizhenbin
https://mailarchive.ietf.org/arch/msg/teas/EiPu6dqziCaZt9-xrfwpLhz9k2M/

Dhruv Dhody
https://mailarchive.ietf.org/arch/msg/teas/oAkcqsfXs752prHEHyXn1x0UJrk/

qzhao@ethericnetworks.com
https://mailarchive.ietf.org/arch/msg/teas/HCxll9py_n1d4Xae7QAnEYsaLVE/

kinghe@tencent.com
[Response Missing]

bhassanov@yahoo.com
https://mailarchive.ietf.org/arch/msg/teas/o8I0aVnZ7o3ueq0aTwxMNpomkyg/

Luyuan Fang
https://mailarchive.ietf.org/arch/msg/teas/VlJoL063l6fdkWNy44naLY_En6k/

chaozhou_us@yahoo.com
https://mailarchive.ietf.org/arch/msg/teas/PAknHmVu915NijdYOndi9E8Xo7U/

Boris.zhang@telus.com
[Response Missing]

Artsiom Rachytski
https://mailarchive.ietf.org/arch/msg/teas/zRvdD8WIrLC1lWKBZlTZRYtY-BU/

anton.gulida@life.com.by
[Response Missing]

Request for posting confirmation emailed to previous authors: Anton Gulida , Artem Rachitskiy , Boris Khasanov , Chao Zhou , Dhruv Dhody , Luyuan Fang , Quintin Zhao , Telus Communications , Zekung Ke , Zhenbin Li , teas-chairs@ietf.org

Request for posting confirmation emailed to previous authors: teas-chairs@ietf.org, Anton Gulida , Chao Zhou , Zhenbin Li , Boris Khasanov , Luyuan Fang , Artem Rachitskiy , Dhruv Dhody , Quintin Zhao , Zekung Ke , Telus Communications

Request for posting confirmation emailed to previous authors: Telus Communications , Artem Rachitskiy , Zhenbin Li , teas-chairs@ietf.org, Boris Khasanov , Dhruv Dhody , Luyuan Fang , Anton Gulida , Zekung Ke , Quintin Zhao , Chao Zhou

Request for posting confirmation emailed to previous authors: Telus Communications , Artem Rachitskiy , Zhenbin Li , teas-chairs@ietf.org, Boris Khasanov , Dhruv Dhody , Luyuan Fang , Anton Gulida , Zekung Ke , Quintin Zhao , Chao Zhou

Request for posting confirmation emailed to previous authors: Telus Communications , Artem Rachitskiy , Chao Zhou , Boris Khasanov , teas-chairs@ietf.org, Luyuan Fang , Zekung Ke , Quintin Zhao , Zhenbin Li

Request for posting confirmation emailed to previous authors: Telus Communications , Artem Rachitskiy , Zhenbin Li , Boris Khasanov , teas-chairs@ietf.org, Luyuan Fang , Zekung Ke , Quintin Zhao , Chao Zhou