Problem Statement, Gap Analysis, and Requirements for Inter-Domain Source Address Validation
draft-ietf-savnet-inter-domain-problem-statement-21

The following Last Call announcement was sent out (ends 2026-10-01):

From: The IESG
To: IETF-Announce
CC: draft-ietf-savnet-inter-domain-problem-statement@ietf.org, gengnan@huawei.com, james.n.guichard@futurewei.com, savnet-chairs@ietf.org, savnet@ietf.org
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (Problem Statement, Gap Analysis, and Requirements for Inter-Domain Source Address Validation) to Informational RFC


The IESG has received a request from the Source Address Validation in
Intra-domain and Inter-domain Networks WG (savnet) to consider the following
document: - 'Problem Statement, Gap Analysis, and Requirements for
Inter-Domain
  Source Address Validation'
  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 2026-10-01. 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 analyzes the problem space and provides a gap analysis
  of existing inter-domain source address validation (SAV) mechanisms.
  Based on these findings, it outlines the technical requirements for
  future improvements.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-savnet-inter-domain-problem-statement/



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

# Shepherd Write-Up

*This version is dated 15 July 2026.*

Shepherd's note: This document (draft-ietf-savnet-inter-domain-problem-statement) lays out the problem statement, gap analysis, and requirements for inter-domain SAV, while intra-domain SAV is covered separately in draft-ietf-savnet-intra-domain-problem-statement. The area reviewer and AD feedback on the intra-domain draft that also applies to this inter-domain SAV document has been considered by the authors of this document.


## 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?

  Broad agreement.

  During the first WGLC, the draft received broad support and got a significant amount of feedback. As the draft was made many updates, the WG initiated a second WGLC to further request the feedback from the WG. The authors have addressed all the comments received during the two WGLCs.

  1st WGLC (from 2026-02-16 to 2026-03-01)
  - Start the WGLC: https://mailarchive.ietf.org/arch/msg/savnet/wGibJ06FhjTED5GEEmKlVSGf8uI/
  - Address all WGLC comments: https://mailarchive.ietf.org/arch/msg/savnet/ATTuOaS9Bvj_vOEXSlEMA-Vmh3s/ and https://mailarchive.ietf.org/arch/msg/savnet/cVlKaU0JU4qwYv2uBUqRN-USzFE/

  2nd WGLC (from 2026-06-02 to 2026-06-16)
  - Start the WGLC: https://mailarchive.ietf.org/arch/msg/savnet/0uz4ATRwtd6jB5GXkPOHj1grJ50/
  - End the WGLC: https://mailarchive.ietf.org/arch/msg/savnet/JbyJtYcYzshnlnz-767B9oeOQ6c/
  - Have completed addressing all WGLC comments: https://mailarchive.ietf.org/arch/msg/savnet/tRlTAOMHG6lUILQfmUoIRBFWDrA/

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

  No.

3. Has anyone threatened an appeal or otherwise indicated extreme discontent? If
  so, please summarize the areas of conflict in separate email messages to the
  responsible Area Director. (It should be in a separate email because this
  questionnaire is publicly available.)

  No.

4. For protocol documents, are there existing implementations of the contents of
  the document? Have a significant number of potential implementers indicated
  plans to implement? Are any existing implementations reported somewhere,
  either in the document itself (as [RFC 7942][3] recommends) or elsewhere
  (where)?

  N/A. It is not a protocol document. This document provides the problem statement and gap analysis of existing inter-domain SAV mechanisms, and outlines the requirements for future improvements.


## 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 analyzes limitations of existing SAV techniques and summarizes requirements for future SAV improvements based on inter-domain SAV scenarios. Given its inter-domain focus, the draft bears some relevance to the IDR and SIDROPS Working Groups. That said, the document does not propose extensions to specific protocols or mechanisms—such as BGP extensions or new RPKI object definitions. Discussions on this draft therefore remain centered primarily on SAV mechanisms themselves, with most discussions taking place within SAVNET WG meetings and its mailing list.

  Some people from IDR and SIDROPS are active participants in SAVNET WG, and this draft has received thorough review input from them throughout ongoing discussions.

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?

  This document is necessary. The document's procedures are clear and complete. I think the current version is ready to be handled to the responsible Area Director.
 
  As a WG participant and the shepherd, I made several careful reviews on the document. The authors have addressed my comments well. My main reviews are as follows:

  Before 1st WGLC: https://mailarchive.ietf.org/arch/msg/savnet/40yy9W5Y8t_owBJsMVzP4IaVULs/
  During 1st WGLC: https://mailarchive.ietf.org/arch/msg/savnet/jNfSGoabDulasVSvy-4kEOhtZRo/
  After 2nd WGLC: https://mailarchive.ietf.org/arch/msg/savnet/D_wLLpOugBFsGM3t629EObxvWGM/

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?

    At the time of this writeup, the early review for the RTG Area has just commenced, while early reviews for other areas have not yet kicked off.

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?

    Informational. The document focuses on problem statement, gap analysis, and requirements. It delivers actionable insights for engineers deploying and enhancing SAV solutions.

    Yes, 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.

    Yes. And, no IPR disclosures have been submitted directly on this document.

    IPR disclosures from the Authors:

    (1) Dan Li, tolidan@tsinghua.edu.cn
    WGLC: https://mailarchive.ietf.org/arch/msg/savnet/2MQzLDVfn1Jn4DR19J3QqDDHE4w/
    WG adoption call: https://mailarchive.ietf.org/arch/msg/savnet/hN2hj7cHIjxAP9Pqypia7sTXIaw/

    (2) Lancheng Qin, qlc19@mails.tsinghua.edu.cn
    WGLC: https://mailarchive.ietf.org/arch/msg/savnet/f2OO6FQXc20aO2_BQd4LB25GTa4/
    WG adoption call: https://mailarchive.ietf.org/arch/msg/savnet/crH0COt-PcpMjzX62rFzp0JGA_o/

    (3) Libin Liu, liulb@zgclab.edu.cn
    WGLC: https://mailarchive.ietf.org/arch/msg/savnet/a-P3eSg4by26e0Awot9i-uQ4pC4/
    WG adoption call: https://mailarchive.ietf.org/arch/msg/savnet/MOK9TSsxvcXWWtGAWwi-m1VEig8/

    (4) Mingqing Huang, huangmingqing@huawei.com
    WGLC: https://mailarchive.ietf.org/arch/msg/savnet/0Kq8gswv_ryF_rEBxzwz4yuDYf4/
    WG adoption call: https://mailarchive.ietf.org/arch/msg/savnet/G92gYlIn8M-1M7j6D_ElNIwLSBk/

    (5) Sriram, Kotikalapudi, kotikalapudi.sriram@nist.gov
    WGLC: https://mailarchive.ietf.org/arch/msg/savnet/tqiBLlhZC-3Nj2qnDRiqDRGsDp0/
    WG adoption call: https://mailarchive.ietf.org/arch/msg/savnet/4a0sOjaa7Fecerc4hlL_rLqoeME/

    (6) Nan Geng, gengnan@huawei.com (Not in the author list now, listed as a contributor)
    WG adoption call: https://mailarchive.ietf.org/arch/msg/savnet/ZkC9Z-xPevDDvGISjwiwQIRKB14/

    (7) Jianping Wu, jianping@cernet.edu.cn (Not in the author list now)
    WG adoption call: https://mailarchive.ietf.org/arch/msg/savnet/VjgcFGbgcfVD2KxoG_m0Tx83uAs/

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.

    All authors are active in the SAVNET WG. There is no argument regarding the author, editor and contributor lists in the working group mailing list. The total number of authors on the front page is five.

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.)

    No. The authors have addressed all the nits raised in the WG.

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

    No. Note that, an Experimental RFC (i.e., RFC5210) is taken as a normative reference in this Informational document.

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

    None. All normative references 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.

    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]).

    No IANA actions are required.

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.

    No IANA actions are required.

[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://wiki.ietf.org/group/ops/yang-review-tools
[5]: https://www.rfc-editor.org/rfc/rfc8342.html
[6]: https://wiki.ietf.org/group/iesg/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/

# Shepherd Write-Up

*This version is dated 15 July 2026.*

Shepherd's note: This document (draft-ietf-savnet-inter-domain-problem-statement) lays out the problem statement, gap analysis, and requirements for inter-domain SAV, while intra-domain SAV is covered separately in draft-ietf-savnet-intra-domain-problem-statement. The area reviewer and AD feedback on the intra-domain draft that also applies to this inter-domain SAV document has been considered by the authors of this document.


## 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?

  Broad agreement.

  During the first WGLC, the draft received broad support and got a significant amount of feedback. As the draft was made many updates, the WG initiated a second WGLC to further request the feedback from the WG. The authors have addressed all the comments received during the two WGLCs.

  1st WGLC (from 2026-02-16 to 2026-03-01)
  - Start the WGLC: https://mailarchive.ietf.org/arch/msg/savnet/wGibJ06FhjTED5GEEmKlVSGf8uI/
  - Address all WGLC comments: https://mailarchive.ietf.org/arch/msg/savnet/ATTuOaS9Bvj_vOEXSlEMA-Vmh3s/ and https://mailarchive.ietf.org/arch/msg/savnet/cVlKaU0JU4qwYv2uBUqRN-USzFE/

  2nd WGLC (from 2026-06-02 to 2026-06-16)
  - Start the WGLC: https://mailarchive.ietf.org/arch/msg/savnet/0uz4ATRwtd6jB5GXkPOHj1grJ50/
  - End the WGLC: https://mailarchive.ietf.org/arch/msg/savnet/JbyJtYcYzshnlnz-767B9oeOQ6c/
  - Have completed addressing all WGLC comments: https://mailarchive.ietf.org/arch/msg/savnet/tRlTAOMHG6lUILQfmUoIRBFWDrA/

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

  No.

3. Has anyone threatened an appeal or otherwise indicated extreme discontent? If
  so, please summarize the areas of conflict in separate email messages to the
  responsible Area Director. (It should be in a separate email because this
  questionnaire is publicly available.)

  No.

4. For protocol documents, are there existing implementations of the contents of
  the document? Have a significant number of potential implementers indicated
  plans to implement? Are any existing implementations reported somewhere,
  either in the document itself (as [RFC 7942][3] recommends) or elsewhere
  (where)?

  N/A. It is not a protocol document. This document provides the problem statement and gap analysis of existing inter-domain SAV mechanisms, and outlines the requirements for future improvements.


## 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 analyzes limitations of existing SAV techniques and summarizes requirements for future SAV improvements based on inter-domain SAV scenarios. Given its inter-domain focus, the draft bears some relevance to the IDR and SIDROPS Working Groups. That said, the document does not propose extensions to specific protocols or mechanisms—such as BGP extensions or new RPKI object definitions. Discussions on this draft therefore remain centered primarily on SAV mechanisms themselves, with most discussions taking place within SAVNET WG meetings and its mailing list.

  Some people from IDR and SIDROPS are active participants in SAVNET WG, and this draft has received thorough review input from them throughout ongoing discussions.

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?

  This document is necessary. The document's procedures are clear and complete. I think the current version is ready to be handled to the responsible Area Director.
 
  As a WG participant and the shepherd, I made several careful reviews on the document. The authors have addressed my comments well. My main reviews are as follows:

  Before 1st WGLC: https://mailarchive.ietf.org/arch/msg/savnet/40yy9W5Y8t_owBJsMVzP4IaVULs/
  During 1st WGLC: https://mailarchive.ietf.org/arch/msg/savnet/jNfSGoabDulasVSvy-4kEOhtZRo/
  After 2nd WGLC: https://mailarchive.ietf.org/arch/msg/savnet/D_wLLpOugBFsGM3t629EObxvWGM/

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?

    At the time of this writeup, the early review for the RTG Area has just commenced, while early reviews for other areas have not yet kicked off.

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?

    Informational. The document focuses on problem statement, gap analysis, and requirements. It delivers actionable insights for engineers deploying and enhancing SAV solutions.

    Yes, 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.

    Yes. And, no IPR disclosures have been submitted directly on this document.

    IPR disclosures from the Authors:

    (1) Dan Li, tolidan@tsinghua.edu.cn
    WGLC: https://mailarchive.ietf.org/arch/msg/savnet/2MQzLDVfn1Jn4DR19J3QqDDHE4w/
    WG adoption call: https://mailarchive.ietf.org/arch/msg/savnet/hN2hj7cHIjxAP9Pqypia7sTXIaw/

    (2) Lancheng Qin, qlc19@mails.tsinghua.edu.cn
    WGLC: https://mailarchive.ietf.org/arch/msg/savnet/f2OO6FQXc20aO2_BQd4LB25GTa4/
    WG adoption call: https://mailarchive.ietf.org/arch/msg/savnet/crH0COt-PcpMjzX62rFzp0JGA_o/

    (3) Libin Liu, liulb@zgclab.edu.cn
    WGLC: https://mailarchive.ietf.org/arch/msg/savnet/a-P3eSg4by26e0Awot9i-uQ4pC4/
    WG adoption call: https://mailarchive.ietf.org/arch/msg/savnet/MOK9TSsxvcXWWtGAWwi-m1VEig8/

    (4) Mingqing Huang, huangmingqing@huawei.com
    WGLC: https://mailarchive.ietf.org/arch/msg/savnet/0Kq8gswv_ryF_rEBxzwz4yuDYf4/
    WG adoption call: https://mailarchive.ietf.org/arch/msg/savnet/G92gYlIn8M-1M7j6D_ElNIwLSBk/

    (5) Sriram, Kotikalapudi, kotikalapudi.sriram@nist.gov
    WGLC: https://mailarchive.ietf.org/arch/msg/savnet/tqiBLlhZC-3Nj2qnDRiqDRGsDp0/
    WG adoption call: https://mailarchive.ietf.org/arch/msg/savnet/4a0sOjaa7Fecerc4hlL_rLqoeME/

    (6) Nan Geng, gengnan@huawei.com (Not in the author list now, listed as a contributor)
    WG adoption call: https://mailarchive.ietf.org/arch/msg/savnet/ZkC9Z-xPevDDvGISjwiwQIRKB14/

    (7) Jianping Wu, jianping@cernet.edu.cn (Not in the author list now)
    WG adoption call: https://mailarchive.ietf.org/arch/msg/savnet/VjgcFGbgcfVD2KxoG_m0Tx83uAs/

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.

    All authors are active in the SAVNET WG. There is no argument regarding the author, editor and contributor lists in the working group mailing list. The total number of authors on the front page is five.

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.)

    No. The authors have addressed all the nits raised in the WG.

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

    No. Note that, an Experimental RFC (i.e., RFC5210) is taken as a normative reference in this Informational document.

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

    None. All normative references 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.

    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]).

    No IANA actions are required.

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.

    No IANA actions are required.

[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://wiki.ietf.org/group/ops/yang-review-tools
[5]: https://www.rfc-editor.org/rfc/rfc8342.html
[6]: https://wiki.ietf.org/group/iesg/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/