Multi-segment SD-WAN via Cloud DCs
draft-ietf-rtgwg-multisegment-sdwan-11

# Document Shepherd Write-Up for Group Documents

*This version is dated Oct, 2025.*


## 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?

While there was not widespread support, there was more than sufficient WG support for the document, and no unaddressed concerns..

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

There was no significant controversy regarding the document.

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.)

There have been no threats of appeal that I have heard of.

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)?

The base GENEVE protocol (RFC 8926) is widely implemented and deployed. The Sub-TLVs defined in this document are new extensions. However, no formal implementation reports (per RFC 7942) are currently available.

## 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.

The draft is closely related to the work previously done in the NVO3 Working Group, which defined and standardized the GENEVE encapsulation (RFC 8926). Since NVO3 has been closed, the authors and RTGWG chairs have circulated this draft to the NVO3 mailing list for review and feedback. There were no objections raised to the addition of the new Sub-TLVs defined in this document. The content aligns with the encapsulation model standardized by NVO3 and does not conflict with other IETF technologies.

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.

There is no formal language or other constructs that require formal expert review in this draft.

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]?

There is no YANG in this draft.

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 are no formal specifications of this form, and thus no such checks apply

## 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.  The shepherd has reviewed the document over several iterations. As far as I can tell, it is now clear, factually correct, and ready to be processed by the AD.

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?

The Routing Area does not have such a list of common issues.  As this document falls squarely within the routing area, I do not believe there are problems with common concerns from other areas.

11. What type of RFC publication is being requested on the IETF stream ([Best
    Current Practice][12], [Proposed Standard, Internet Standard][13],
    [Informational, Experimental or Historic][14])? Why is this the proper type
    of RFC? Do all Datatracker state attributes correctly reflect this intent?

The document defines new protocol elements (a GENEVE Option Class and Sub-TLV registry) requiring IANA action, thus Standards Track is appropriate.

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

Yes, and all authors have confirmed their disclosure obligations to the Chairs.

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.

To the best of my knowledge, all authors listed on the front page are aware of this document being progressed and are willing to be listed as front page authors.  There are no specially named contributors, and there are a number of people whose contributions are acknowledged.

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.)

The only I-D nits complaints are to drafts which have been revised
        since this was last revised, which I understand to be a non-issue.  I
        do not see any issues related to the content guidelines on
        authors.ietf.org.

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

The arrangement of references seems appropriate to me.

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 normative references are freely available.  More specifically, all normative references are RFCs.

17. Are there any normative downward references (see [RFC 3967][9] and [BCP
    97][10]) that are not already listed in the [DOWNREF registry][17]? If so,
    list them.

No.

18. Are there normative references to documents that are not ready to be
    submitted to the IESG for publication or are otherwise in an unclear state?
    If so, what is the plan for their completion?

No.

19. Will publication of this document change the status of any existing RFCs? If
    so, does the Datatracker metadata correctly reflect this and are those RFCs
    listed on the title page, in the abstract, and discussed in the
    introduction? If not, explain why and point to the part of the document
    where the relationship of this document to these other RFCs is discussed.

No.

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

The document has been reviewed by the Shepherd and this is ready for publication.
The IANA action is clear, and early allocation was approved by IANA.

21. List any new IANA registries that require Designated Expert Review for
    future allocations. Are the instructions to the Designated Expert clear?

  An IANA allocation is requested and approved.

    Please include suggestions of designated experts, if appropriate.

N/A

Document Title:  Multi-segment SD-WAN via Cloud DCs
Authors:  K. Majumdar, L. Dunbar, V. Kasiviswanathan, A. Ramchandra, A. Choudhary
Intended Status:  Standards Track
Shepherd:  Chongfeng Xie
Responsible AD:  Jim Guichard

(1) Type of RFC
Standards Track.
The document defines new protocol elements (a GENEVE Option Class and Sub-TLV registry) requiring IANA action, thus Standards Track is appropriate.

(2) Technical Summary
This document specifies a method for connecting multiple SD-WAN segments via Cloud Backbones without decrypting/re-encrypting user traffic at Cloud Gateways. The approach uses GENEVE encapsulation (RFC 8926) to carry metadata alongside IPsec-encrypted payloads.
The draft defines:
  - A new GENEVE Option Class for Multi-Segment SD-WAN.
  - Sub-TLVs for metadata (e.g., egress GW, region restriction, exclusion, authentication).
  - Procedures for ingress/egress Cloud GWs.
  - Error handling, manageability, and security considerations.

(3) Working Group Summary
The document has not yet gone through Working Group Last Call. However, based on the discussion within RTGWG and the importance of the technical problem addressed, the document is considered ready to proceed to WGLC. No significant controversy remains.

(4) Document Quality
The draft is well written and includes diagrams, deployment motivation, and detailed considerations for security and manageability. External review has already influenced improvements. Further review by NVO3/GENEVE experts may be helpful, but no fundamental issues are expected.

(5) IPR
Each author has confirmed compliance with BCP 78/79.
No IPR disclosures have been filed against this document.

(6) Consensus
There was sufficient WG support for the document, with positive feedback from both vendors and operators.

(7) Appeals
No threats of appeal or indications of extreme discontent.

(8) ID Nits and References
No unresolved nits.
Normative references are to stable RFCs (e.g., RFC 8174, RFC 8926).
Informative references include relevant drafts (e.g., Edge Discovery, Lightweight Authentication), but publication is not blocked by their progress.

(9) IANA Considerations
The draft requests:
  1. Allocation of a new GENEVE Option Class (0x0163).
  2. Creation of a new IANA registry Multi-Segment SD-WAN Sub-TLVs (assignment policy: IETF Review).
  3. Registration of Sub-TLVs defined in this document.
These requests are clearly described in Section 11 and follow standard practice.

(10) Security Considerations
The draft provides a detailed threat analysis. Key points:
  - GENEVE headers are not encrypted → risk of metadata tampering.
  - Mitigations: optional HMAC Sub-TLV, or AH/ESP-NULL for stronger protection.
  - Cross-domain deployments require authentication/authorization policy enforcement.
  - Payload confidentiality is preserved by IPsec.
Security considerations are judged sufficient for Standards Track.

(11) Conclusion
The Shepherd has reviewed the document carefully and believes it is technically sound and ready for advancement. The security and IANA considerations are clearly specified. The draft aligns with existing standards and deployment practices.  Based on the technical discussions in RTGWG and the relevance of the problem it addresses, it is judged ready for WGLC.

Document Title:      Multi-segment SD-WAN via Cloud DCs
Authors:                  K. Majumdar, L. Dunbar, V. Kasiviswanathan, A. Ramchandra, A. Choudhary
Intended Status:      Standards Track
Shepherd:                Chongfeng Xie
Responsible AD:      Jim Guichard

(1) Type of RFC
Standards Track.
The document defines new protocol elements (a GENEVE Option Class and Sub-TLV registry) requiring IANA action, thus Standards Track is appropriate.

(2) Technical Summary
This document specifies a method for connecting multiple SD-WAN segments via Cloud Backbones without decrypting/re-encrypting user traffic at Cloud Gateways. The approach uses GENEVE encapsulation (RFC 8926) to carry metadata alongside IPsec-encrypted payloads.
The draft defines:
  - A new GENEVE Option Class for Multi-Segment SD-WAN.
  - Sub-TLVs for metadata (e.g., egress GW, region restriction, exclusion, authentication).
  - Procedures for ingress/egress Cloud GWs.
  - Error handling, manageability, and security considerations.

(3) Working Group Summary
The document has not yet gone through Working Group Last Call. However, based on the discussion within RTGWG and the importance of the technical problem addressed, the document is considered ready to proceed to WGLC. No significant controversy remains.

(4) Document Quality
The draft is well written and includes diagrams, deployment motivation, and detailed considerations for security and manageability. External review has already influenced improvements. Further review by NVO3/GENEVE experts may be helpful, but no fundamental issues are expected.

(5) IPR
Each author has confirmed compliance with BCP 78/79.
No IPR disclosures have been filed against this document.

(6) Consensus
There was sufficient WG support for the document, with positive feedback from both vendors and operators.

(7) Appeals
No threats of appeal or indications of extreme discontent.

(8) ID Nits and References
No unresolved nits.
Normative references are to stable RFCs (e.g., RFC 8174, RFC 8926).
Informative references include relevant drafts (e.g., Edge Discovery, Lightweight Authentication), but publication is not blocked by their progress.

(9) IANA Considerations
The draft requests:
  1. Allocation of a new GENEVE Option Class (0x0163).
  2. Creation of a new IANA registry Multi-Segment SD-WAN Sub-TLVs (assignment policy: IETF Review).
  3. Registration of Sub-TLVs defined in this document.
These requests are clearly described in Section 11 and follow standard practice.

(10) Security Considerations
The draft provides a detailed threat analysis. Key points:
  - GENEVE headers are not encrypted → risk of metadata tampering.
  - Mitigations: optional HMAC Sub-TLV, or AH/ESP-NULL for stronger protection.
  - Cross-domain deployments require authentication/authorization policy enforcement.
  - Payload confidentiality is preserved by IPsec.
Security considerations are judged sufficient for Standards Track.

(11) Conclusion
The Shepherd has reviewed the document carefully and believes it is technically sound and ready for advancement. The security and IANA considerations are clearly specified. The draft aligns with existing standards and deployment practices.  Based on the technical discussions in RTGWG and the relevance of the problem it addresses, it is judged ready for WGLC.