Propagating Explicit Congestion Notification Across IP Tunnel Headers Separated by a Shim
draft-ietf-tsvwg-rfc6040update-shim-23

[Ballot comment]
Thanks for this impressive spec. I have just a few comments/questions.

- I am quite bemused by the proportion of this document devoted to exegesis rather than specification, but at least it makes an interesting read.

- In,

        For those not under IETF
  control, it is RECOMMENDED that implementations of encapsulation and
  decapsulation comply with RFC 6040.  It is also RECOMMENDED that
  their specifications are updated to add a requirement to comply with
  RFC 6040 (as updated by the present document).

I don’t think you can point a BCP 14 “RECOMMENDED” at the owners of those specifications and expect it to have any force, any more than you can update their specifications, for the same reason.  This seems to be an exuberant use of all caps to mean “we really do suggest this quite enthusiastically”, but that’s not what BCP 14 is.

- Has this work been liaised to 3GPP (and any other SDOs I might have missed that are potentially affected)?

[Ballot comment]
# GEN AD review of draft-ietf-tsvwg-rfc6040update-shim-22

CC @larseggert

## Comments

### Boilerplate

This document uses the RFC2119 keywords "RECOMMENDED", "SHOULD", "SHALL", "MUST
NOT", "MUST", "REQUIRED", "OPTIONAL", "MAY", "SHALL NOT", and "SHOULD NOT", but
does not contain the recommended RFC8174 boilerplate. (It contains some text
with a similar beginning.)

Document has a TLP Section 6.c.iii "pre-5378" boilerplate. Is this really
needed?

## Nits

All comments below are about very minor potential issues that you may choose to
address in some way - or ignore - as you see fit. Some were flagged by
automated tools (via https://github.com/larseggert/ietf-reviewtool), so there
will likely be some false positives. There is no need to let me know what you
did with these suggestions.

### Typos

#### Section 4, paragraph 6
```
-          decribed in [decap-test]);
+          described in [decap-test]);
+            +
```

### URLs

These URLs in the document can probably be converted to HTTPS:

* http://bobbriscoe.net/

### Grammar/style

#### Section 1, paragraph 1
```
y encapsulate an inner IP header. Instead they can encapsulate headers such
                                  ^^^^^^^
```
A comma may be missing after the conjunctive/linking adverb "Instead".

#### Section 3, paragraph 7
```
entations that predated the RFC. Therefore it would have been unreasonable t
                                ^^^^^^^^^
```
A comma may be missing after the conjunctive/linking adverb "Therefore".
(Also elsewhere in the document.)

#### Section 3.2, paragraph 4
```
ket forwarded beyond the tunnel. Otherwise the non-ECN egress could discard
                                ^^^^^^^^^
```
A comma may be missing after the conjunctive/linking adverb "Otherwise".
(Also elsewhere in the document.)

#### Section 4, paragraph 11
```
ogic, copying the ECN field as a side-effect of copying the DSCP is a serious
                                ^^^^^^^^^^^
```
Did you mean "side effect" (=adverse effect, unintended consequence)? Open
compounds are not hyphenated.

#### Section 6.1.1.2.1, paragraph 8
```
cification will need to be followed, e.g Explicit Congestion Marking in MPLS
                                    ^^^
```
The abbreviation "e.g." (= for example) requires two periods.

#### Section 6.1.2, paragraph 4
```
N field in the outer IPv6 header. However the specification does not mention
                                  ^^^^^^^
```
A comma may be missing after the conjunctive/linking adverb "However".

## Notes

This review is in the ["IETF Comments" Markdown format][ICMF], You can use the
[`ietf-comments` tool][ICT] to automatically convert this review into
individual GitHub issues. Review generated by the [`ietf-reviewtool`][IRT].

[ICMF]: https://github.com/mnot/ietf-comments/blob/main/format.md
[ICT]: https://github.com/mnot/ietf-comments
[IRT]: https://github.com/larseggert/ietf-reviewtool

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

Similar to draft-ietf-tsvwg-ecn-encap-guidelines-21, I am wondering why this document contains the disclaimer for pre-RFC5378 work.

[Ballot discuss]
# Éric Vyncke, INT AD, comments for draft-ietf-tsvwg-rfc6040update-shim-21

Thank you for the work put into this document.

Please find below one blocking DISCUSS points (easy to address), some non-blocking COMMENT points (but replies would be appreciated even if only for my own education), and some nits.

Special thanks to Gorry Fairhurst for the shepherd's detailed write-up including the WG consensus *but it lacks* the justification of the intended status.

Other thanks to Donald Eastlake, the Internet directorate reviewer (at my request), please consider this int-dir review:
https://datatracker.ietf.org/doc/review-ietf-tsvwg-rfc6040update-shim-20-intdir-telechat-eastlake-2023-11-22/ (and I have noticed Bob's reply)

I hope that this review helps to improve the document,

Regards,

-éric


# DISCUSS (blocking)

As noted in https://www.ietf.org/blog/handling-iesg-ballot-positions/, a DISCUSS ballot is a request to have a discussion on the following topics:

## Wrong BCP14 ...

Section 2 MUST use the correct BCP 14 (I told you that this was trivial)

[Ballot comment]

# COMMENTS (non-blocking)


## Section 3.1

It is just a comment, no need to reply, but I do not agree with `Digging to arbitrary depths to find an inner IP header within an encapsulation is strictly a layering violation`, the encapsulating routing is probably doing the encaps based on the future inner IP header (routing to a tunnel interface). Anyway, just a comment.

## Section 6

Suggest removing the long expired draft-ietf-intarea-gue (and possibly others).

Suggest to add RFC 8986 as it also has a Ethernet next-header.

## Section 6.1.2

Please note that NHRP, RFC 2332, is sometimes used to set up GRE tunnels.

## Section 6.1.3

Teredo... a glimpse of the past back in 2023 ? More seriously, I do not mind having this section, but Teredo is no more used. Writing `existing Teredo deployments safe` in an IETF document looks so weird.

# NITS (non-blocking / cosmetic)

## Use of v4 and v6

While I usually say "v4" or "v6", I strongly suggest to write "IPv4" and "IPv6".

[Ballot comment]
Hi,

Thanks for this document, I found it interesting to read.  A couple of minor comments for you to consider:

(1) p 5, sec 4.  Making a non-ECN Tunnel Ingress Safe by Configuration

      Whether or not an ingress implementation claims compliance with
      RFC 6040, RFC 4301 or RFC3168, when the outer tunnel header is IP
      (v4 or v6), if possible, the operator MUST configure the ingress
      to zero the outer ECN field in any of the following cases:

As a minor comment, I wonder whether RFCs should be specifying requirements on people (i.e., operators), or whether it would be better to place the requirement on the deployment.


(2) p 10, sec 6.1.1.  L2TP (v2 and v3) ECN Extension

  L2TP maintainers are RECOMMENDED to implement the ECN extension to
  L2TPv2 and L2TPv3 defined in Section 6.1.1.2 below, in order to
  provide the benefits of ECN [RFC8087], whenever a node within an L2TP
  tunnel becomes the bottleneck for an end-to-end traffic flow.

Similarly to my previous comment, should the RFC 2119 requirement be placed on the maintainers, or should it be placed on an updated versions of L2TP?

Regards,
Rob

Comments from the experts:

I read over this and I’m a bit confused.

Section 6.1.1.2.1. Defines an “LCCE Capability AVP”, as a bit-mask with one bit defined.
However, Section 7 calls it “ECN Capability AVP” and does not define the flags.

I have two recommendations:
1. Name an AVP with “ECN” since that’s what it’s signaling.
2. Is the bit-mask really needed?

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

IANA has completed its review of draft-ietf-tsvwg-rfc6040update-shim-19. If any part of this review is inaccurate, please let us know.

IANA understands that, upon approval of this document, there is a single action which we must complete.

In the Control Message Attribute Value Pairs registry in the Layer Two Tunneling Protocol "L2TP" registry group located at:

https://www.iana.org/assignments/l2tp-parameters/

a single new registration is to be made as follows:

Attribute Type: [ TBD-at-Registration ]
Description: ECN Capability
Reference: [ RFC-to-be ]

As this document requests a registration in an Expert Review or Specification Required (see RFC 8126) registry, we have initiated the required Expert Review via a separate request. This review must be completed before the document's IANA state can be changed to "IANA OK."

We understand that this is the only action required to be completed upon approval of this document.

NOTE: The action requested in this document will not be completed until the document has been approved for publication as an RFC. This message is meant only to confirm the action that will be performed.

For definitions of IANA review states, please see:

https://datatracker.ietf.org/help/state/draft/iana-review

Thank you,

David Dong
IANA Services Sr. Specialist

The following Last Call announcement was sent out (ends 2023-11-02):

From: The IESG
To: IETF-Announce
CC: David Black , draft-ietf-tsvwg-rfc6040update-shim@ietf.org, gorry@erg.abdn.ac.uk, martin.h.duke@gmail.com, tsvwg-chairs@ietf.org, tsvwg@ietf.org
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (Propagating Explicit Congestion Notification Across IP Tunnel Headers Separated by a Shim) to Proposed Standard


The IESG has received a request from the Transport and Services Working Group
WG (tsvwg) to consider the following document: - 'Propagating Explicit
Congestion Notification Across IP Tunnel Headers
  Separated by a Shim'
  as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits final
comments on this action. Please send substantive comments to the
last-call@ietf.org mailing lists by 2023-11-02. 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


  RFC 6040 on "Tunnelling of Explicit Congestion Notification" made the
  rules for propagation of ECN consistent for all forms of IP in IP
  tunnel.  This specification updates RFC 6040 to clarify that its
  scope includes tunnels where two IP headers are separated by at least
  one shim header that is not sufficient on its own for wide area
  packet forwarding.  It surveys widely deployed IP tunnelling
  protocols that use such shim header(s) and updates the specifications
  of those that do not mention ECN propagation (that is RFC 2661, RFC
  3931, RFC 2784, RFC 4380 and RFC 7450, which respectively specify
  L2TPv2, L2TPv3, GRE, Teredo and AMT).  This specification also
  updates RFC 6040 with configuration requirements needed to make any
  legacy tunnel ingress safe.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-tsvwg-rfc6040update-shim/



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

The chairs have decided this draft is nearly ready to proceed and here is the write-up for g draft-ietf-tsvwg-rfc6040update-shim.


This document when published will reference ietf-tsvwg-ecn-encap-guidelines, and it is requested the two RFCs are published together.


Best wishes,

# Document Shepherd Write-Up for Group Documents: draft-ietf-tsvwg-rfc6040update-shim


*This version is dated 4 July 2022.*

## Document History

1. Does the working group (WG) consensus represent the strong concurrence of a
  few individuals, with others being silent, or did it reach broad agreement?

There was strong support from the working group for publishing a BCP in this space and this need was confirmed by INTAREA comments on the work, because the scope includes a group of INTAREA specifications. The document's purpose is to ensure safe propagation of the ECN field over tunnels.

When published, this specification will update RFCs: 6040, 2661, 2784, 3931, 4380, 7450.

The WG reached consensus following a WGLC that concluded on 25th April 2021, and rev 14 was thought to resolve the WG comments. This document has a dependency on ietf-tsvwg-ecn-encap-guidelines, and that document has stalled publication of this draft. Since rev-14, the author has continued to correct text and respond to Shepherd comments.

This document is now ready to proceed.

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)?

There are a wide variety of tunnel specifications and implementations, some of these
are thought to follow the design described in this document.

## 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.

Yes. This document updates a number of IETF protocols and provides guidance for some non-IETF documents. It is expected that OPS and INT Area reviews will be helpful.

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.

Not applicable.

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]?

Not applicable.

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.

Not applicable.


## 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 is ready.

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?

Checked - this document directly relates to tunnels and the use of ECN.

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?

This targets publication as a Standards Track (PS).

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 editor has confirmed there is no known IPR relating to this ID,
and that he is content with his name being present when published.

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.

Yes.

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.)

Checked.

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

No.

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

None.

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.

When published, this PS will update RFCs: 6040, 2661, 2784, 3931, 4380, 7450.

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 has been reviewed and it includes a request to IANA from the L3TP protocol registry.


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 ID does not create a new registry.

Notes:

This document when published will reference ietf-tsvwg-ecn-encap-guidelines, and it is requested the two RFCs are published together.

The chairs have decided this draft is nearly ready to proceed and here is the write-up for g draft-ietf-tsvwg-rfc6040update-shim.
This document when published will reference ietf-tsvwg-ecn-encap-guidelines, and it is requested the two RFCs are published together.

Gorry Fairhurst
(Document Shepherd)

The chairs have decided this draft is nearly ready to proceed and here is the write-up for g draft-ietf-tsvwg-rfc6040update-shim.


This document when published will reference ietf-tsvwg-ecn-encap-guidelines, and it is requested the two RFCs are published together.


Best wishes,

# Document Shepherd Write-Up for Group Documents: draft-ietf-tsvwg-rfc6040update-shim


*This version is dated 4 July 2022.*

## Document History

1. Does the working group (WG) consensus represent the strong concurrence of a
  few individuals, with others being silent, or did it reach broad agreement?

There was strong support from the working group for publishing a BCP in this space and this need was confirmed by INTAREA comments on the work, because the scope includes a group of INTAREA specifications. The document's purpose is to ensure safe propagation of the ECN field over tunnels.

When published, this specification will update RFCs: 6040, 2661, 2784, 3931, 4380, 7450.

The WG reached consensus following a WGLC that concluded on 25th April 2021, and rev 14 was thought to resolve the WG comments. This document has a dependency on ietf-tsvwg-ecn-encap-guidelines, and that document has stalled publication of this draft. Since rev-14, the author has continued to correct text and respond to Shepherd comments.

This document is now ready to proceed.

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)?

There are a wide variety of tunnel specifications and implementations, some of these
are thought to follow the design described in this document.

## 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.

Yes. This document updates a number of IETF protocols and provides guidance for some non-IETF documents. It is expected that OPS and INT Area reviews will be helpful.

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.

Not applicable.

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]?

Not applicable.

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.

Not applicable.


## 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 is ready.

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?

Checked - this document directly relates to tunnels and the use of ECN.

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?

This targets publication as a Standards Track (PS).

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 editor has confirmed there is no known IPR relating to this ID,
and that he is content with his name being present when published.

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.

Yes.

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.)

Checked.

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

No.

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

None.

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.

When published, this PS will update RFCs: 6040, 2661, 2784, 3931, 4380, 7450.

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 has been reviewed and it includes a request to IANA from the L3TP protocol registry.


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 ID does not create a new registry.

Notes:

This document when published will reference ietf-tsvwg-ecn-encap-guidelines, and it is requested the two RFCs are published together.

The chairs have decided this draft is nearly ready to proceed and here is the write-up for g draft-ietf-tsvwg-rfc6040update-shim.


This document when published will reference ietf-tsvwg-ecn-encap-guidelines, and it is requested the two RFCs are published together.


Best wishes,

Gorry Fairhurst
(Document Shepherd)

=======================================================

# Document Shepherd Write-Up for Group Documents: draft-ietf-tsvwg-rfc6040update-shim


*This version is dated 4 July 2022.*

## Document History

1. Does the working group (WG) consensus represent the strong concurrence of a
  few individuals, with others being silent, or did it reach broad agreement?

There was strong support from the working group for publishing a BCP in this space and this need was confirmed by INTAREA comments on the work, because the scope includes a group of INTAREA specifications. The document's purpose is to ensure safe propagation of the ECN field over tunnels.

When published, this specification will update RFCs: 6040, 2661, 2784, 3931, 4380, 7450.

The WG reached consensus following a WGLC that concluded on 25th April 2021, and rev 14 was thought to resolve the WG comments. This document has a dependency on ietf-tsvwg-ecn-encap-guidelines, and that document has stalled publication of this draft. Since rev-14, the author has continued to correct text and respond to Shepherd comments.

This document is now ready to proceed.

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)?

There are a wide variety of tunnel specifications and implementations, some of these
are thought to follow the design described in this document.

## 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.

Yes. This document updates a number of IETF protocols and provides guidance for some non-IETF documents. It is expected that OPS and INT Area reviews will be helpful.

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.

Not applicable.

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]?

Not applicable.

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.

Not applicable.


## 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 is ready.

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?

Checked - this document directly relates to tunnels and the use of ECN.

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?

This targets publication as a Standards Track (PS).

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 editor has confirmed there is no known IPR relating to this ID,
and that he is content with his name being present when published.

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.

Yes.

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.)

Checked.

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

No.

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

None.

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.

When published, this PS will update RFCs: 6040, 2661, 2784, 3931, 4380, 7450.

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 has been reviewed and it includes a request to IANA from the L3TP protocol registry.


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 ID does not create a new registry.

Notes:

This document when published will reference ietf-tsvwg-ecn-encap-guidelines, and it is requested the two RFCs are published together.