Happy Eyeballs Version 2: Better Connectivity Using Concurrency
draft-ietf-v6ops-rfc6555bis-07

[Ballot comment]
Substantive Comments:

- I agree with Adam's comments about normative language.

-4, 2nd paragraph, last sentence:
"across networks" and "network changes" are ambiguous. I think you are talking about moving a device from one access network to another, but "across networks" could be interpreted to mean "sending the data across networks". "Network changes" could refer to changes in network configuration.

-10: I don't understand what you mean by "direct" vs "indirect" security considerations.

Editorial Comments:

- Abstract: Please mention that this obsoletes 6555 in the abstract. (The intro already does so.)

- 7.2, last paragraph: The pattern "... recommended at 2 seconds" does not make grammatical sense. I would assume there are missing words, but I see the same pattern occur several times in the document. I suggest "recommended to be..."

[Ballot comment]
Summary:

I think it's great that we continue to refine the means for making rapid connections in dual-stack environments, and want to thank the authors and working group for putting together a well-written and easy-to-follow document. I have some concerns about distinguishing normative requirements from an "example algorithm" that can be used to meet them, and would like to see better clarity around the relationship between this document and existing, deployed implementations of RFC6555.

Details:

The abstract claims that the document provides an "example" algorithm, while the main text of the document describes the algorithm as "RECOMMENDED" (using normative language), as well as having a variety of other normative statements made regarding its implementation. Given that the document is serving the dual purpose of laying out requirements and giving an exemplary (which I would take to mean "non-normative") algorithm that satisfies those requirements, I would *strongly* recommend removing normative language from the description of the exemplary algorithm.

In order to make that task easier -- and to clarify the intention of the lower-cased word "recommended" in phrases like "The recommended minimum value is 100 milliseconds" -- I would further suggest that this document adopt the new RFC8174 template instead of using the old RFC2119 template.

That said, there appears to be a random mix of uppercase and non-uppercase "recommended" even when describing the same general concept (e.g., the timer cited above is "recommended," while the timeout for processing DNS responses after a connection is "RECOMMENDED") -- I suggest an editing pass that generally looks at how these terms are used and ensures that normative versus non-normative uses are properly distinguished.

The reason I'm focusing so carefully on normative versus non-normative language use in general, and on carefully making the algorithm itself non-normative in particular ties to the rationale for obsoleting RFC6555. In an earlier response to Mirja's DISCUSS, Tommy Pauly said:

> A "simple" implementation of the 6555bis algorithm is still
> aligned with the algorithm in 6555, and we would like to see
> new implementations taking the nuances of the new algorithm
> description into account.

Which makes perfect sense. I've seen evidence that this point -- that an implementation of the RFC6555 algorithm is fully compliant with the v2 document -- has been broadly missed by the implementation community. See, for example: https://groups.google.com/a/chromium.org/forum/m/#!topic/net-dev/GQaqi5WVlPY  (and, FWIW, I've had similar private feedback from the relevant decision makers inside Mozilla regarding web browser implementations).

To clarify this situation, I think it is really necessary to include text in Appendix A that indicates roughly the same thing as Tommy's text above does.

[Ballot comment]
Summary:

I think it's great that we continue to refine the means for making rapid connections in dual-stack environments, and want to thank the authors and working group for putting together a well-written and easy-to-follow document. I have some concerns about distinguishing normative requirements from an "example algorithm" that can be used to meet them, and would like to see better clarity around the relationship between this document and existing, deployed implementations of RFC6555.

Details:

The abstract claims that the document provides an "example" algorithm, while the main text of the document describes the algorithm as "RECOMMENDED" (using normative language), as well as having a variety of other normative statements made regarding its implementation. Given that the document is serving the dual purpose of laying out requirements and giving an exemplary (which I would take to mean "non-normative") algorithm that satisfies that algorithm, I would *strongly* recommend removing normative language from the description of the exemplary algorithm.

In order to make that task easier -- and to clarify the intention of the lower-cased word "recommended" in phrases like "The recommended minimum value is 100 milliseconds" -- I would further suggest that this document adopt the new RFC8174 template instead of using the old RFC2119 template.

That said, there appears to be a random mix of uppercase and non-uppercase "recommended" even when describing the same general concept (e.g., the timer cited above is "recommended," while the timeout for processing DNS responses after a connection is "RECOMMENDED") -- I suggest an editing pass that generally looks at how these terms are used and ensures that normative versus non-normative uses are properly distinguished.

The reason I'm focusing so carefully on normative versus non-normative language use in general, and on carefully making the algorithm itself non-normative in particular ties to the rationale for obsoleting RFC6555. In an earlier response to Mirja's DISCUSS, Tommy Pauly said:

> A "simple" implementation of the 6555bis algorithm is still
> aligned with the algorithm in 6555, and we would like to see
> new implementations taking the nuances of the new algorithm
> description into account.

Which makes perfect sense. I've seen evidence that this point -- that an implementation of the RFC6555 algorithm is fully compliant with the v2 document -- has been broadly missed by the implementation community. See, for example: https://groups.google.com/a/chromium.org/forum/m/#!topic/net-dev/GQaqi5WVlPY  (and, FWIW, I've had similar private feedback from the relevant decision makers inside Mozilla regarding web browser implementations).

To clarify this situation, I think it is really necessary to include text in Appendix A that indicates roughly the same thing as Tommy's text above does.

[Ballot comment]
I'm removing my discuss as the authors have confirmed that there is strong consensus in the working group to obsolete RFC6555, and edited the text in the intro accordingly. As mentioned to the authors directly already, the abstract should mention this as well!

Thanks also for addressing my other comments!

[Ballot comment]
This document should provide a rationale for why you are favoring v6 over v4 addresses when v4 addresses resolve first. Is there some technical reason (e.g., it works better) or is there just a political reason (we want to push people to v6). I could live with either, but the document should be clear IMO.

[Ballot comment]
Someome id-nits:

    (See RFCs 3967 and 4897 for information about using normative references

    to lower-maturity documents in RFCs)


  == Missing Reference: 'Section 3' is mentioned on line 120, but not defined

  == Missing Reference: 'Section 4' is mentioned on line 164, but not defined

  == Missing Reference: 'Section 5' is mentioned on line 202, but not defined

  == Missing Reference: 'Section 6' is mentioned on line 169, but not defined

    Summary: 0 errors (**), 0 flaws (~~), 4 warnings (==), 3 comments (--).

[Ballot discuss]
I would totally be a yes on this document, but I would like to first discuss a processing issue: I do not agree with the assessment that this draft should obsolete RFC6555. The draft itself says: "This document expands on "Happy Eyeballs" [RFC6555]..." which sounds to me like an update. Further I believe RFC6555 is still a valid algorithm that can be used as specified, also RFC6555 provides probably more useful background info that is not captured by this new draft. I would recommend to update instead. Also, in any case the obsolete or update should to be mentioned in the abstract.

[Ballot comment]
Question on the equation in section 5:
"MAX( 1.25 * RTT_MEAN + 4 * RTT_VARIANCE, 2 *RTT_MEAN )"
While it is not well explained how RTT_MEAN and RTT_VARIANCE are measured, I would recommend to just use *3RTT instead (where RTT is the value you have cached for a certain destination address, no matter how that has been measured/calculated), as RFC2988 says:

"When the first RTT measurement R is made, the host MUST set

            SRTT <- R
            RTTVAR <- R/2
            RTO <- SRTT + max (G, K*RTTVAR)"

which translates to 3*R if you only have one value.

I also don't think that is is necessary to talk about exponential backoff. To me that seems more confusing than helpful here.

However, it might be helpful to note that 3*RTT also means that in the best case the handshake is already completed before you try the next address. And further, I would assume that you might still want to have a fixed max default value (of e.g. 300ms or 250ms?) because otherwise on paths where you have high delay sequential probing might be too slow, no?

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet Standard,
Informational, Experimental, or Historic)? Why is this the proper type of RFC?
Is this type of RFC indicated in the title page header?

Proposed Standard. This is appropriate because it describes procedures that hosts should execute
when attached to dual-stack networks. The status is reflected in the header.

(2) The IESG approval announcement includes a Document Announcement Write-Up. Please provide
such a Document Announcement Write-Up. Recent examples can be found in the "Action"
announcements for approved documents. The approval announcement contains the following
sections:

Technical Summary:

Many communication protocols operated over the modern Internet use
host names.  These often resolve to multiple IP addresses, each of
which may have different performance and connectivity
characteristics.  Since specific addresses or address families (IPv4
or IPv6) may be blocked, broken, or sub-optimal on a network, clients
that attempt multiple connections in parallel have a higher chance of
establishing a connection sooner.  This document specifies
requirements for algorithms that reduce this user-visible delay and
provides an example algorithm.

Working Group Summary:

Strong WG consensus was achieved within six months of document introduction.

Document Quality:

Are there existing implementations of the protocol?

The current versions of macOS (Sierra) and iOS (10) implement the Happy Eyeballs V2 spec
as described.

Have a significant number of vendors indicated their plan to implement the specification?

Yes

Are there any reviewers that merit special mention as having done a thorough review, e.g.,
one that resulted in important changes or a conclusion that the document had no substantive
issues? If there was a MIB Doctor, Media Type or other expert review, what was its course
(briefly)? In the case of a Media Type review, on what date was the request posted?

Comments were received from Mark Andrews, Mikael Abrahamsson, Jinmei Tatuya, Stephen Strowes,
james woodyatt, Tim Chown and Sander Steffann

Personnel:

Who is the Document Shepherd? Who is the Responsible Area Director?

Ron Bonica is the document shepherd
Warren Kumari is the responsible AD

(3) Briefly describe the review of this document that was performed by the
Document Shepherd. If this version of the document is not ready for publication,
please explain why the document is being forwarded to the IESG.

I re-read the document, re-read each of the mailing list comments and confered with my fellow ADs
to make sure that they read consensus as I did.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews
that have been performed?

No

(5) Do portions of the document need review from a particular or from broader perspective,
e.g., security, operational complexity, AAA, DNS, DHCP, XML, or internationalization?
If so, describe the review that took place.

No

(6) Describe any specific concerns or issues that the Document Shepherd has with this
document that the Responsible Area Director and/or the IESG should be aware of?
For example, perhaps he or she is uncomfortable with certain parts of the document,
or has concerns whether there really is a need for it. In any event, if the WG has
discussed those issues and has indicated that it still wishes to advance the document,
detail those concerns here.

None

(7) Has each author confirmed that any and all appropriate IPR disclosures required for full
conformance with the provisions of BCP 78 and BCP 79 have already been filed. If not,
explain why?

Yes

(8) Has an IPR disclosure been filed that references this document? If so, summarize
any WG discussion and conclusion regarding the IPR disclosures.

No

[ Update: 2017-09-16 by Warren Kumari -- the authors have informed us that have just learnt that there **may** be some IPR associated with the document, and are talking to their lawyer folk to get clarification ]

[Update: 2017-10-6 by Ron Bonica -- Apple has disclosed IPR. See https://datatracker.ietf.org/ipr/3077/. This disclosure came after WGLC. ]

(9) How solid is the WG consensus behind this document? Does it represent the strong
concurrence of a few individuals, with others being silent, or does the WG as a whole
understand and agree with it?

This draft elicitted ~40 messages on the mailing list. Most were supportive, some had technical
concerns that were addressed.

(10) Has anyone threatened an appeal or otherwise indicated extreme discontent?
If so, please summarise 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

(11) Identify any ID nits the Document Shepherd has found in this document.
(See http://www.ietf.org/tools/idnits/ and the Internet-Drafts Checklist). Boilerplate
checks are not enough; this check needs to be thorough.

None

(12) Describe how the document meets any required formal review criteria, such as the
MIB Doctor, media type, and URI type reviews.

This document will be reviewed by the General, OPS and Transport Area review teams

(13) Have all references within this document been identified as either normative or informative?

(14) Are there normative references to documents that are not ready for advancement or
are otherwise in an unclear state? If such normative references exist, what is the plan
for their completion?

No

(15) Are there downward normative references references (see RFC 3967)? If so,
list these downward references to support the Area Director in the Last Call procedure.

No

(16) Will publication of this document change the status of any existing RFCs?
Are those RFCs listed on the title page header, listed in the abstract, and discussed
in the introduction? If the RFCs are not listed in the Abstract and Introduction,
explain why, and point to the part of the document where the relationship of this document
to the other RFCs is discussed. If this information is not in the document, explain why the
WG considers it unnecessary.

This document obsoletes RFC 6555 (Happy Eyeballs V1)

(17) 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 protocol extensions that the document makes are associated with the appropriate
reservations in IANA registries. Confirm that any referenced IANA registries have been
clearly identified. Confirm that newly created IANA registries include a detailed
specification of the initial contents for the registry, that allocations procedures
for future registrations are defined, and a reasonable name for the new registry has
been suggested (see RFC 5226).

This memo includes no request to IANA.

(18) List any new IANA registries that require Expert Review for future allocations.
Provide any public guidance that the IESG would find useful in selecting the IANA Experts
for these new registries.

None

(19) Describe reviews and automated checks performed by the Document Shepherd to validate
sections of the document written in a formal language, such as XML code, BNF rules, MIB
definitions, etc.

Nit-checker

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

The IANA Services Operator has reviewed draft-ietf-v6ops-rfc6555bis-05, 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.

Thank you,

Sabrina Tanamal
IANA Services Specialist

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet Standard,
Informational, Experimental, or Historic)? Why is this the proper type of RFC?
Is this type of RFC indicated in the title page header?

Proposed Standard. This is appropriate because it describes procedures that hosts should execute
when attached to dual-stack networks. The status is reflected in the header.

(2) The IESG approval announcement includes a Document Announcement Write-Up. Please provide
such a Document Announcement Write-Up. Recent examples can be found in the "Action"
announcements for approved documents. The approval announcement contains the following
sections:

Technical Summary:

Many communication protocols operated over the modern Internet use
host names.  These often resolve to multiple IP addresses, each of
which may have different performance and connectivity
characteristics.  Since specific addresses or address families (IPv4
or IPv6) may be blocked, broken, or sub-optimal on a network, clients
that attempt multiple connections in parallel have a higher chance of
establishing a connection sooner.  This document specifies
requirements for algorithms that reduce this user-visible delay and
provides an example algorithm.

Working Group Summary:

Strong WG consensus was achieved within six months of document introduction.

Document Quality:

Are there existing implementations of the protocol?

The current versions of macOS (Sierra) and iOS (10) implement the Happy Eyeballs V2 spec
as described.

Have a significant number of vendors indicated their plan to implement the specification?

Yes

Are there any reviewers that merit special mention as having done a thorough review, e.g.,
one that resulted in important changes or a conclusion that the document had no substantive
issues? If there was a MIB Doctor, Media Type or other expert review, what was its course
(briefly)? In the case of a Media Type review, on what date was the request posted?

Comments were received from Mark Andrews, Mikael Abrahamsson, Jinmei Tatuya, Stephen Strowes,
james woodyatt, Tim Chown and Sander Steffann

Personnel:

Who is the Document Shepherd? Who is the Responsible Area Director?

Ron Bonica is the document shepherd
Warren Kumari is the responsible AD

(3) Briefly describe the review of this document that was performed by the
Document Shepherd. If this version of the document is not ready for publication,
please explain why the document is being forwarded to the IESG.

I re-read the document, re-read each of the mailing list comments and confered with my fellow ADs
to make sure that they read consensus as I did.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews
that have been performed?

No

(5) Do portions of the document need review from a particular or from broader perspective,
e.g., security, operational complexity, AAA, DNS, DHCP, XML, or internationalization?
If so, describe the review that took place.

No

(6) Describe any specific concerns or issues that the Document Shepherd has with this
document that the Responsible Area Director and/or the IESG should be aware of?
For example, perhaps he or she is uncomfortable with certain parts of the document,
or has concerns whether there really is a need for it. In any event, if the WG has
discussed those issues and has indicated that it still wishes to advance the document,
detail those concerns here.

None

(7) Has each author confirmed that any and all appropriate IPR disclosures required for full
conformance with the provisions of BCP 78 and BCP 79 have already been filed. If not,
explain why?

Yes

(8) Has an IPR disclosure been filed that references this document? If so, summarize
any WG discussion and conclusion regarding the IPR disclosures.

No

[ Update: 2017-09-16 by Warren Kumari -- the authors have informed us that have just learnt that there **may** be some IPR associated with the document, and are talking to their lawyer folk to get clarification ]

(9) How solid is the WG consensus behind this document? Does it represent the strong
concurrence of a few individuals, with others being silent, or does the WG as a whole
understand and agree with it?

This draft elicitted ~40 messages on the mailing list. Most were supportive, some had technical
concerns that were addressed.

(10) Has anyone threatened an appeal or otherwise indicated extreme discontent?
If so, please summarise 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

(11) Identify any ID nits the Document Shepherd has found in this document.
(See http://www.ietf.org/tools/idnits/ and the Internet-Drafts Checklist). Boilerplate
checks are not enough; this check needs to be thorough.

None

(12) Describe how the document meets any required formal review criteria, such as the
MIB Doctor, media type, and URI type reviews.

This document will be reviewed by the General, OPS and Transport Area review teams

(13) Have all references within this document been identified as either normative or informative?

(14) Are there normative references to documents that are not ready for advancement or
are otherwise in an unclear state? If such normative references exist, what is the plan
for their completion?

No

(15) Are there downward normative references references (see RFC 3967)? If so,
list these downward references to support the Area Director in the Last Call procedure.

No

(16) Will publication of this document change the status of any existing RFCs?
Are those RFCs listed on the title page header, listed in the abstract, and discussed
in the introduction? If the RFCs are not listed in the Abstract and Introduction,
explain why, and point to the part of the document where the relationship of this document
to the other RFCs is discussed. If this information is not in the document, explain why the
WG considers it unnecessary.

This document obsoletes RFC 6555 (Happy Eyeballs V1)

(17) 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 protocol extensions that the document makes are associated with the appropriate
reservations in IANA registries. Confirm that any referenced IANA registries have been
clearly identified. Confirm that newly created IANA registries include a detailed
specification of the initial contents for the registry, that allocations procedures
for future registrations are defined, and a reasonable name for the new registry has
been suggested (see RFC 5226).

This memo includes no request to IANA.

(18) List any new IANA registries that require Expert Review for future allocations.
Provide any public guidance that the IESG would find useful in selecting the IANA Experts
for these new registries.

None

(19) Describe reviews and automated checks performed by the Document Shepherd to validate
sections of the document written in a formal language, such as XML code, BNF rules, MIB
definitions, etc.

Nit-checker

The following Last Call announcement was sent out (ends 2017-09-26):

From: The IESG
To: IETF-Announce
CC: Ron Bonica , v6ops@ietf.org, rbonica@juniper.net, v6ops-chairs@ietf.org, draft-ietf-v6ops-rfc6555bis@ietf.org, warren@kumari.net
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Happy Eyeballs Version 2: Better Connectivity Using Concurrency) to Proposed Standard


The IESG has received a request from the IPv6 Operations WG (v6ops) to
consider the following document: - 'Happy Eyeballs Version 2: Better
Connectivity Using Concurrency'
  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
ietf@ietf.org mailing lists by 2017-09-26. 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


  Many communication protocols operated over the modern Internet use
  host names.  These often resolve to multiple IP addresses, each of
  which may have different performance and connectivity
  characteristics.  Since specific addresses or address families (IPv4
  or IPv6) may be blocked, broken, or sub-optimal on a network, clients
  that attempt multiple connections in parallel have a higher chance of
  establishing a connection sooner.  This document specifies
  requirements for algorithms that reduce this user-visible delay and
  provides an example algorithm.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-v6ops-rfc6555bis/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-v6ops-rfc6555bis/ballot/


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

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet Standard,
Informational, Experimental, or Historic)? Why is this the proper type of RFC?
Is this type of RFC indicated in the title page header?

Proposed Standard. This is appropriate because it describes procedures that hosts should execute
when attached to dual-stack networks. The status is reflected in the header.

(2) The IESG approval announcement includes a Document Announcement Write-Up. Please provide
such a Document Announcement Write-Up. Recent examples can be found in the "Action"
announcements for approved documents. The approval announcement contains the following
sections:

Technical Summary:

Many communication protocols operated over the modern Internet use
host names.  These often resolve to multiple IP addresses, each of
which may have different performance and connectivity
characteristics.  Since specific addresses or address families (IPv4
or IPv6) may be blocked, broken, or sub-optimal on a network, clients
that attempt multiple connections in parallel have a higher chance of
establishing a connection sooner.  This document specifies
requirements for algorithms that reduce this user-visible delay and
provides an example algorithm.

Working Group Summary:

Strong WG consensus was achieved within six months of document introduction.

Document Quality:

Are there existing implementations of the protocol?

The current versions of macOS (Sierra) and iOS (10) implement the Happy Eyeballs V2 spec
as described.

Have a significant number of vendors indicated their plan to implement the specification?

Yes

Are there any reviewers that merit special mention as having done a thorough review, e.g.,
one that resulted in important changes or a conclusion that the document had no substantive
issues? If there was a MIB Doctor, Media Type or other expert review, what was its course
(briefly)? In the case of a Media Type review, on what date was the request posted?

Comments were received from Mark Andrews, Mikael Abrahamsson, Jinmei Tatuya, Stephen Strowes,
james woodyatt, Tim Chown and Sander Steffann

Personnel:

Who is the Document Shepherd? Who is the Responsible Area Director?

Ron Bonica is the document shepherd
Warren Kumari is the responsible AD

(3) Briefly describe the review of this document that was performed by the
Document Shepherd. If this version of the document is not ready for publication,
please explain why the document is being forwarded to the IESG.

I re-read the document, re-read each of the mailing list comments and confered with my fellow ADs
to make sure that they read consensus as I did.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews
that have been performed?

No

(5) Do portions of the document need review from a particular or from broader perspective,
e.g., security, operational complexity, AAA, DNS, DHCP, XML, or internationalization?
If so, describe the review that took place.

No

(6) Describe any specific concerns or issues that the Document Shepherd has with this
document that the Responsible Area Director and/or the IESG should be aware of?
For example, perhaps he or she is uncomfortable with certain parts of the document,
or has concerns whether there really is a need for it. In any event, if the WG has
discussed those issues and has indicated that it still wishes to advance the document,
detail those concerns here.

None

(7) Has each author confirmed that any and all appropriate IPR disclosures required for full
conformance with the provisions of BCP 78 and BCP 79 have already been filed. If not,
explain why?

Yes

(8) Has an IPR disclosure been filed that references this document? If so, summarize
any WG discussion and conclusion regarding the IPR disclosures.

No

(9) How solid is the WG consensus behind this document? Does it represent the strong
concurrence of a few individuals, with others being silent, or does the WG as a whole
understand and agree with it?

This draft elicitted ~40 messages on the mailing list. Most were supportive, some had technical
concerns that were addressed.

(10) Has anyone threatened an appeal or otherwise indicated extreme discontent?
If so, please summarise 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

(11) Identify any ID nits the Document Shepherd has found in this document.
(See http://www.ietf.org/tools/idnits/ and the Internet-Drafts Checklist). Boilerplate
checks are not enough; this check needs to be thorough.

None

(12) Describe how the document meets any required formal review criteria, such as the
MIB Doctor, media type, and URI type reviews.

This document will be reviewed by the General, OPS and Transport Area review teams

(13) Have all references within this document been identified as either normative or informative?

(14) Are there normative references to documents that are not ready for advancement or
are otherwise in an unclear state? If such normative references exist, what is the plan
for their completion?

No

(15) Are there downward normative references references (see RFC 3967)? If so,
list these downward references to support the Area Director in the Last Call procedure.

No

(16) Will publication of this document change the status of any existing RFCs?
Are those RFCs listed on the title page header, listed in the abstract, and discussed
in the introduction? If the RFCs are not listed in the Abstract and Introduction,
explain why, and point to the part of the document where the relationship of this document
to the other RFCs is discussed. If this information is not in the document, explain why the
WG considers it unnecessary.

This document obsoletes RFC 6555 (Happy Eyeballs V1)

(17) 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 protocol extensions that the document makes are associated with the appropriate
reservations in IANA registries. Confirm that any referenced IANA registries have been
clearly identified. Confirm that newly created IANA registries include a detailed
specification of the initial contents for the registry, that allocations procedures
for future registrations are defined, and a reasonable name for the new registry has
been suggested (see RFC 5226).

This memo includes no request to IANA.

(18) List any new IANA registries that require Expert Review for future allocations.
Provide any public guidance that the IESG would find useful in selecting the IANA Experts
for these new registries.

None

(19) Describe reviews and automated checks performed by the Document Shepherd to validate
sections of the document written in a formal language, such as XML code, BNF rules, MIB
definitions, etc.

Nit-checker