Media Operations Use Case for an Extended Reality Application on Edge Computing Infrastructure
draft-ietf-mops-ar-use-case-18

[Ballot comment]
Thanks for working on this document. It captures number of important aspect for the potential XR traffic and its operational considerations.

However, I am missing a bit more discussions on the QoS that was mentioned, specially how the application requirement is transfers to the network. Do we have enough tools and techniques to provide such information from the applicaiton to the network? Even if network operators have their own managed edge cloud service, it is unlikely that they provide all the XR application in the devices, hence, somehow the QoS requirements need to be exchanged to provide it from the network. I would like know the authros view on this.

I am also missing some discussions on the different traffic priorities for XR traffic. As XR traffic would combine media and some control traffic, the network might need to provide and provision for - say different latency for those. If I am right to think in such a way then it pocesses some opeational reqirements on the network. 

Thanks to Wesley Eddy for the nice TSVART review.

some nits

- Please explain what is heavy-tailed? and there are two version of heavy-tailed ( the other one is without hyphen )

- Plus what Roman captured in his review, I am not repeating them here.

[Ballot comment]
Thanks for working on this document. It captures number of important aspect for the potential XR traffic and its operational considerations.

However, I am missing a bit more discussions on the QoS that was mentioned, specially how the application requirement is transfers to the network. Do we have enough tools and techniques to provide such information from the applicaiton to the network? Even if network operators have their own managed edge cloud service, it is unlikely that they provide all the XR application in the devices, hence, somehow the QoS requirements need to be exchanged to provide it from the network. I would like know the authros view on this.

I am also missing some discussions on the different traffic priorities for XR traffic. As XR traffic would combine media and some control traffic, the network might need to provide and provision for - say different latency for those. If I am right to think in such a way then it pocesses some opeational reqirements on the network. 

Thanks to Wesley Eddy for the nice TSVART review.

some nits

- Please explain what is heavy-tailed? and there are two version of heavy-tailed ( the other one is without hyphen )
- Plus what Roman captured in his review, I am not repeating them here.

[Ballot comment]
** Section 1.
  In particular, the edge devices deploy cloud computing
  implementation techniques such as [EDGE_3]:

This doesn’t read right.  How does an “edge device” deploy anything?  The described architecture is likely designed, provisioned, and operated likely by a service provider(s) of some kind.

** Section 1.
  Such techniques enable XR applications requiring low-latency and high
  bandwidth to be delivered by mini-clouds running on proximate edge
  devices.

What is a “mini-cloud”?

** Section 2 and 3.  Section 2 provides a substantial level of detail.  Revisiting the intent of this document being for “network operators who are interested in providing edge computing resources to operationalize the requirements of such applications”, it isn’t clear how this information in Section 2 translates into network requirements outlined in Section 3.

** Section 4.1
  Providing Edge
  server support for the techniques being developed at the DETNET
  Working Group at the IETF could guarantee performance of XR
  applications.

Can this text be more specific – What specific DETNET technology?  Is DETNET used between the edge device and the cloud, or in the cloud?

** Section 4.1.  Per some of the entries in Table 1:
-- Where are these defined?
-- Are these strictly XR applications (e.g., “video conferencing”)?
-- I’m having difficulty linking some of these rows to the use case defined in Section 2.

** Section 4.2.  Similar comments about Table 2 as above.  How do these use cases link to Section 2?

** ** Section 7.
  The security issues for the presented use case are similar to other
  streaming applications.  This document itself introduces no new
  security issues.

No disagreement on the similar.  However, where are these referenced security issues documented?

[Ballot comment]
** Section 1.
  In particular, the edge devices deploy cloud computing
  implementation techniques such as [EDGE_3]:

This doesn’t read right.  How does an “edge device” deploy anything?  The described architecture is likely designed, provisioned, and operated likely by a service provider(s) of some kind.

** Section 1.
  Such techniques enable XR applications requiring low-latency and high
  bandwidth to be delivered by mini-clouds running on proximate edge
  devices.

What is a “mini-cloud”?

** Section 2 and 3.  Section 2 provides a substantial level of detail.  Revisiting the intent of this document being for “network operators who are interested in providing edge computing resources to operationalize the requirements of such applications”, it isn’t clear how this information in Section 2 translates into network requirements outlined in Section 3.

** Section 4.1
  Providing Edge
  server support for the techniques being developed at the DETNET
  Working Group at the IETF could guarantee performance of XR
  applications.

Can this text be more specific – What specific DETNET technology?  Is DETNET used between the edge device and the cloud, or in the cloud?

** Section 4.1.  Per some of the entries in Table 1:
-- Where are these defined?
-- Are these strictly XR applications (e.g., “video conferencing”)?
-- I’m having difficulty linking some of these rows to the use case defined in Section 2.

** Section 4.2.  Similar comments about Table 2 as above.  How do these use cases link to Section 2.

** ** Section 7.
  The security issues for the presented use case are similar to other
  streaming applications.  This document itself introduces no new
  security issues.

No disagreement on the similar.  However, where are these referenced security issues documented?

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

IANA has completed its review of draft-ietf-mops-ar-use-case-15, 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

Request for Last Call review by TSVART Completed: Ready with Issues. Reviewer: Wesley Eddy. Sent review to list. Submission of review completed at an earlier date.

The following Last Call announcement was sent out (ends 2024-04-02):

From: The IESG
To: IETF-Announce
CC: draft-ietf-mops-ar-use-case@ietf.org, evyncke@cisco.com, mops-chairs@ietf.org, mops@ietf.org, stewe@stewe.org
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (Media Operations Use Case for an Extended Reality Application on Edge Computing Infrastructure) to Informational RFC


The IESG has received a request from the Media OPerationS WG (mops) to
consider the following document: - 'Media Operations Use Case for an Extended
Reality Application on Edge
  Computing Infrastructure'
  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 2024-04-02. 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


  This document explores the issues involved in the use of Edge
  Computing resources to operationalize media use cases that involve
  Extended Reality (XR) applications.  In particular, this document
  discusses those applications that run on devices having different
  form factors (such as different physical sizes and shapes) and need
  Edge computing resources to mitigate the effect of problems such as a
  need to support interactive communication requiring low latency,
  limited battery power, and heat dissipation from those devices.  The
  intended audience for this document are network operators who are
  interested in providing edge computing resources to operationalize
  the requirements of such applications.  This document discusses the
  expected behavior of XR applications which can be used to manage the
  traffic.  In addition, the document discusses the service
  requirements of XR applications to be able to run on the network.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-mops-ar-use-case/



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

# 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.
to answer all of them.

This writeup covers draft-ietf-mops-ar-use-case-13.

Initial version: 8/18/2023
updated: 10/23/2023
updated: 11/30/2023

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?
Perhaps “strong concurrence by a few” is a fair characterization.  The shepherd will note, however, that the WG is small, its scope is huge, and the scope of this draft is narrow.  For that reason, anything else but a strong concurrence of a few with silence by the others is to be expected.  In this case, the shepherd does not view this negatively.

2. Was there controversy about particular points, or were there decisions where
the consensus was particularly rough?
None.

3. Has anyone threatened an appeal or otherwise indicated extreme discontent?
AFAIK, no threatened appeals nor otherwise extreme discontent.  Harsh questions were occasionally asked (and answered), but that’s not that unusual in the IETF :-)
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.)
N/A

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 recommends) or elsewhere
(where)?
N/A

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?
The shepherd is not aware of other IETF WGs working on AR/VR operational matters.
Certain groups in 3GPP (including SA1 and SA4) have worked on matters similar to this draft, and there’s a certain overlap in personnel between MOPS participants and participants in those groups.  The shepherd believes that no formal review of the document is required due to its informal nature and the mentioned overlap in personnel.
 
Have those reviews occurred? If yes, describe which
reviews took place.
N/A

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.

None of those expert reviews were solicited, nor required (in the shepherd’s opinion), as the document does not include MIBs, YANG, or media type/URI registrations.

7. If the document contains a YANG module, has the final version of the module
been checked with any of the recommended validation tools for syntax and
formatting validation? If there are any resulting errors or warnings, what is
the justification for not fixing them at this time? Does the YANG module
comply with the Network Management Datastore Architecture (NMDA) as specified
in RFC 8342?
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?
Yes to all of the question.
Elaborating on the “need” for this document: to the best knowledge of the shepherd, no similar document exists; not in the IETF, not in 3GPP, and not in academic circles.  OTOH, a great deal of uncertainty and lack of understanding exists when it comes to operational aspects of forthcoming AR/VR applications, especially when they involve edge computing.  Therefore, while the term “needed” may be debatable, without doubt the document should be useful to some.

10. Several IETF Areas have assembled lists of common issues that their
reviewers encounter. For which areas have such issues been identified
and addressed? For which does this still need to happen in subsequent
reviews?
On 10/27/2023, the authors indicated in a word attachment to an email to the MOPS list “We have reviewed the lists of common issues and can confirm that these issues are not relevant to our draft.”
The shepherd’s opinion is that aligned with the above.

11. What type of RFC publication is being requested on the IETF stream (Best
Current Practice, Proposed Standard, Internet Standard,
Informational, Experimental or Historic)?
Informational
Why is this the proper type
of RFC?
The document does not normatively define anything.

Do all Datatracker state attributes correctly reflect this intent?
With the submission of -13, the datatracker was updated 10/22/23 to reflect status: informational, and to correct the email addresses/affiliations. 


12. Have reasonable efforts been made to remind all authors of the intellectual
property rights (IPR) disclosure obligations described in BCP 79?
The shepherd requested a statement of compliance with BCP79, and such statements were received from both authors around 8/13 on the MOPS mailing list.

To
the best of your knowledge, have all required disclosures been filed?
Yes.

If
not, explain why. If yes, summarize any relevant discussion, including links
to publicly-available messages when applicable.
N/A

13. Has each author, editor, and contributor shown their willingness to be
listed as such? Each author has consented per emails received 8/11 and 8/13.
If the total number of authors and editors on the front page
is greater than five, please provide a justification.
N/A

14. Document any remaining I-D nits in this document. Simply running the idnits
tool is not enough; please review the "Content Guidelines" on
authors.ietf.org. (Also note that the current idnits tool generates
some incorrect warnings; a rewrite is underway.)
Version 14 passes idnits.  The previously missing empty IANA section has been added.

15. Should any informative references be normative or vice-versa? See the IESG
Statement on Normative and Informative References.
As the document is informational in nature and targets to become an informational RFC, only informational references make sense here.  Therefore, all references are informational.

16. List any normative references that are not freely available to anyone. Did
the community have sufficient access to review any such normative
references?
Most references in this document refer to academic papers and their access requires passing the usual hurdles—membership in the academic organization (and relevant chapter), library access, or payment of a nominal download fee.  The shepherd believes that these are not insurmountable hurdles.  Referred standards documents (from 3GPP and the IETF) are available for download.

17. Are there any normative downward references (see RFC 3967 and BCP
97) that are not already listed in the DOWNREF registry? If so,
list them.
N/A as there are no normative references

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?
N/A as there are no normative references

19. Will publication of this document change the status of any existing RFCs?
No
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.
N/A

20. Describe the document shepherd's review of the IANA considerations section,
especially with regard to its consistency with the body of the document.
A dummy IANA section is present.  Nothing else is needed.

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).
N/A

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

# 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.
to answer all of them.

This writeup covers draft-ietf-mops-ar-use-case-13.

Initial version: 8/18/2023
updated: 10/23/2023
updated: 11/30/2023

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?
Perhaps “strong concurrence by a few” is a fair characterization.  The shepherd will note, however, that the WG is small, its scope is huge, and the scope of this draft is narrow.  For that reason, anything else but a strong concurrence of a few with silence by the others is to be expected.  In this case, the shepherd does not view this negatively.

2. Was there controversy about particular points, or were there decisions where
the consensus was particularly rough?
None.

3. Has anyone threatened an appeal or otherwise indicated extreme discontent?
AFAIK, no threatened appeals nor otherwise extreme discontent.  Harsh questions were occasionally asked (and answered), but that’s not that unusual in the IETF :-)
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.)
N/A

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 recommends) or elsewhere
(where)?
N/A

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?
The shepherd is not aware of other IETF WGs working on AR/VR operational matters.
Certain groups in 3GPP (including SA1 and SA4) have worked on matters similar to this draft, and there’s a certain overlap in personnel between MOPS participants and participants in those groups.  The shepherd believes that no formal review of the document is required due to its informal nature and the mentioned overlap in personnel.
 
Have those reviews occurred? If yes, describe which
reviews took place.
N/A

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.

None of those expert reviews were solicited, nor required (in the shepherd’s opinion), as the document does not include MIBs, YANG, or media type/URI registrations.

7. If the document contains a YANG module, has the final version of the module
been checked with any of the recommended validation tools for syntax and
formatting validation? If there are any resulting errors or warnings, what is
the justification for not fixing them at this time? Does the YANG module
comply with the Network Management Datastore Architecture (NMDA) as specified
in RFC 8342?
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?
Yes to all of the question.
Elaborating on the “need” for this document: to the best knowledge of the shepherd, no similar document exists; not in the IETF, not in 3GPP, and not in academic circles.  OTOH, a great deal of uncertainty and lack of understanding exists when it comes to operational aspects of forthcoming AR/VR applications, especially when they involve edge computing.  Therefore, while the term “needed” may be debatable, without doubt the document should be useful to some.

10. Several IETF Areas have assembled lists of common issues that their
reviewers encounter. For which areas have such issues been identified
and addressed? For which does this still need to happen in subsequent
reviews?
On 10/27/2023, the authors indicated in a word attachment to an email to the MOPS list “We have reviewed the lists of common issues and can confirm that these issues are not relevant to our draft.”
The shepherd’s opinion is that aligned with the above.

11. What type of RFC publication is being requested on the IETF stream (Best
Current Practice, Proposed Standard, Internet Standard,
Informational, Experimental or Historic)?
Informational
Why is this the proper type
of RFC?
The document does not normatively define anything.

Do all Datatracker state attributes correctly reflect this intent?
With the submission of -13, the datatracker was updated 10/22/23 to reflect status: informational, and to correct the email addresses/affiliations. 


12. Have reasonable efforts been made to remind all authors of the intellectual
property rights (IPR) disclosure obligations described in BCP 79?
The shepherd requested a statement of compliance with BCP79, and such statements were received from both authors around 8/13 on the MOPS mailing list.

To
the best of your knowledge, have all required disclosures been filed?
Yes.

If
not, explain why. If yes, summarize any relevant discussion, including links
to publicly-available messages when applicable.
N/A

13. Has each author, editor, and contributor shown their willingness to be
listed as such? Each author has consented per emails received 8/11 and 8/13.
If the total number of authors and editors on the front page
is greater than five, please provide a justification.
N/A

14. Document any remaining I-D nits in this document. Simply running the idnits
tool is not enough; please review the "Content Guidelines" on
authors.ietf.org. (Also note that the current idnits tool generates
some incorrect warnings; a rewrite is underway.)
Version 14 passes idnits.  The previously missing empty IANA section has been added.

15. Should any informative references be normative or vice-versa? See the IESG
Statement on Normative and Informative References.
As the document is informational in nature and targets to become an informational RFC, only informational references make sense here.  Therefore, all references are informational.

16. List any normative references that are not freely available to anyone. Did
the community have sufficient access to review any such normative
references?
Most references in this document refer to academic papers and their access requires passing the usual hurdles—membership in the academic organization (and relevant chapter), library access, or payment of a nominal download fee.  The shepherd believes that these are not insurmountable hurdles.  Referred standards documents (from 3GPP and the IETF) are available for download.

17. Are there any normative downward references (see RFC 3967 and BCP
97) that are not already listed in the DOWNREF registry? If so,
list them.
N/A as there are no normative references

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?
N/A as there are no normative references

19. Will publication of this document change the status of any existing RFCs?
No
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.
N/A

20. Describe the document shepherd's review of the IANA considerations section,
especially with regard to its consistency with the body of the document.
A dummy IANA section is present.  Nothing else is needed.

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).
N/A

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