Integration of the Network Service Header (NSH) and Segment Routing for Service Function Chaining (SFC)
draft-ietf-spring-nsh-sr-15

[Ballot comment]
Thanks for the discussion of whether to use a UDP encap to save an IP protocol number. I've cleared; the previous comment still stands though:

Related to the DISCUSS question, it seems as though a few words would be in order, early in the document, about the encapsulation. I do see (now that Jim pointed it out to me OOB :-) that Section 11.1 requests an IP protocol number from IANA, and the rest is arguably "obvious". Nonetheless, it seems worth a few sentences.

Obviously, if Stewart's suggestion to move to a UDP encap were used, that would also call for a few sentences to describe it.

[Ballot comment]
Thanks for working on this specification.

One comment -

I think it should be described why the cache miss event should to be logged. Both the purpose and effect of not logging it. I think so because, this is only occurrence of asking for logging in this whole specification with normative text, hence the importance and effect should be explained well.

[Ballot comment]
# Internet AD comments for draft-ietf-spring-nsh-sr-12
CC @ekline

## Comments

### S5.1, S5.2

* I am not very familiar with the SFC paradigm, so please do correct me or
  ignore me.

  Does this "service-index - 1" cache end up imposing too tight a restriction
  on the SF handling of the NSH, limiting processing to only a single
  function (decrementing the service index by only 1)?

  I naively expected that the SR segment list could move a packet through
  a network of endpoints, but that each endpoint could perhaps trigger
  multiple functions acting on the packet without incurring extra,
  duplicative segments to indicate additional processing on the same node.

### S11.1

* Should the document reference actually RFC 8300 (NSH)?  "This document"
  defines where the IANA allocation comes from but that doesn't really help
  a possible implementer get directly to the required spec.

[Ballot discuss]
Thanks for this clean, easy-to-review document.

I do have one point I'd like to flag. I'm making this a DISCUSS to ensure the IESG has a chance to discuss the point raised, and intend to clear after the telechat.

In his review (https://datatracker.ietf.org/doc/review-ietf-spring-nsh-sr-11-rtgdir-lc-bryant-2022-05-28/) Stewart Bryant makes a good point:

```
There is one point that the IESG should ponder. The authors have asked for a IP
type assignment. This is a limited registry that needs to last the lifetime of
the IP protocol suite. NSH started its life 9 years ago and has been a standard
for 4 years and in all this time has not needed such as allocation. Neither
SRv6 nor NSH are petite or lightweight protocols. So I wonder if the
identification of NSH should happen at the IP layer as proposed, or whether an
intermediate multiplexing layer such as UDP should be used? The extra
processing for UDP is one test and the extra MTU is 8 octets. The decision for
the IESG is whether in their view the extent of deployment and the gain in
performance is such that they should authorise the allocation of the IP type.
```

AFAICT the argument against using a UDP encap is "it's more overhead" (which is true, but I think Stewart's point is that the UDP overhead is pretty small as a fraction of the SRv6 and NSH overheads). Anyway, it seems like it would be good to at least consider this question.

[Ballot comment]
Related to the DISCUSS question, it seems as though a few words would be in order, early in the document, about the encapsulation. I do see (now that Jim pointed it out to me OOB :-) that Section 11.1 requests an IP protocol number from IANA, and the rest is arguably "obvious". Nonetheless, it seems worth a few sentences.

Obviously, if Stewart's suggestion to move to a UDP encap were used, that would also call for a few sentences to describe it.

[Ballot comment]
Hi,

Thanks for this document.  I have one minor comment/question:

Minor level comments:                                                                                                                                                                                                                                       
                                                                                                                                                                                                                                                           
(1) p 9, sec 4.  SR-based SFC with Integrated NSH Service Plane

            +------------+        +------------+        +------------+
            |  S(SF1)  |        |  S(SF2)  |        | F:Inner Pkt|
            +------------+        +------------+        +------------+
            |  S(SFF2)  |        | N(100,254) |
            +------------+        +------------+
            |  S(SF2)  |        | F:Inner Pkt|
            +------------+        +------------+
            | N(100,255) |
            +------------+
            | F:Inner Pkt|
            +------------+

From this diagram, it wasn't clear to me why the segments have got from "SF1, SFF2, SF2" at step (1) to just "SF2" at step (4).

Regards,
Rob

[Ballot comment]

Thank you for the work put into this document.

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

Special thanks to Bruno Decraene for the shepherd's detailed write-up including the WG consensus *and* the justification of the intended status.

Please note that Dave Thaler is the Internet directorate reviewer (at my request) and you may want to consider this int-dir review as well when it will be available (no need to wait for it though):
https://datatracker.ietf.org/doc/draft-ietf-spring-nsh-sr/reviewrequest/17400/
Even a double thanks to Dave as he also did an early int-dir review (and I noted the authors' reaction to this early review).

I hope that this review helps to improve the document,

Regards,

-éric

# COMMENTS (non blocking)

## Acronyms

May I suggest to also expand acronyms at first use *outside* the abstract ? E.g., SFF

## Section 3

The reader will understand better figure 1 with:

* the packet outside border having a different border than the functions/devices (e.g., using '/' rather than '|')
* the packet headers being closer to (1) and (4)
* referring in the text to the steps (1), (2), ...

## Section 5.2

Should the cache be emptied when a packet came back ? or on time-out (as either no reply or multiple replies could be expected). The reader has to wait until section 9 to get some hints (and it is unclear whether the caching refers to the section 5.2 caching).

## Section 9

In absence of cache entry, should the text specify that the packet is dropped ? Or should a ICMP sent back to the SF ?

# NITS (non blocking / cosmetic)

## Section 6.2

s/128 bits IPv6 address/128-bit IPv6 address/ ?

[Ballot comment]

# GEN AD review of draft-ietf-spring-nsh-sr-12

CC @larseggert

Thanks to Linda Dunbar for the General Area Review Team (Gen-ART) review
(https://mailarchive.ietf.org/arch/msg/gen-art/pCpXOVzbOjel0Wrp8PjJ9sUeY98).

## Comments

### Section 1.1, paragraph 0
```
    The dynamic enforcement of a service-derived and adequate forwarding
    policy for packets entering a network that supports advanced Service
    Functions (SFs) has become a key challenge for network operators.
    For instance, cascading SFs at the 3GPP (Third Generation Partnership
    Project) Gi interface (N6 interface in 5G architecture) has shown
    limitations such as 1) redundant classification features must be
    supported by many SFs to execute their function, 2) some SFs receive
    traffic that they are not supposed to process (e.g., TCP proxies
    receiving UDP traffic) which inevitably affects their dimensioning
    and performance, and 3) an increased design complexity related to the
    properly ordered invocation of several SFs.
```
Could we perhaps find an IETF example to motivate this? It feels a bit odd
that the first paragraph in the introduction immediately points to a 3GPP
shortcoming, and it's the only motivational example given...

### Boilerplate

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

### Inclusive language

Found terminology that should be reviewed for inclusivity; see
https://www.rfc-editor.org/part2/#inclusive_language for background and more
guidance:

* Term `master`; alternatives might be `active`, `central`, `initiator`,
  `leader`, `main`, `orchestrator`, `parent`, `primary`, `server`
* Term `native`; alternatives might be `built-in`, `fundamental`, `ingrained`,
  `intrinsic`, `original`

## 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.

### Outdated references

Document references `draft-ietf-spring-sr-service-programming-05`, but `-07` is
the latest available revision.

### Grammar/style

#### "Abstract", paragraph 1
```
ce Function Chaining (SFC) in an efficient manner while maintaining separati
                          ^^^^^^^^^^^^^^^^^^^^^^
```
Consider replacing this phrase with the adverb "efficiently" to avoid
wordiness.

#### Section 1, paragraph 1
```
ose problems, and to decouple the services topology from the underlying phys
                                  ^^^^^^^^
```
An apostrophe may be missing.

#### Section 3, paragraph 11
```
ct forwarding paths for example). Further note that the above example can al
                                  ^^^^^^^
```
A comma may be missing after the conjunctive/linking adverb "Further".

#### Section 3, paragraph 17
```
n is used between SFF and SF). In addition the SFF strips the SR information
                                  ^^^^^^^^
```
A comma may be missing after the conjunctive/linking adverb "addition".

#### Section 4, paragraph 7
```
H processing logic for SRv6. The pseudo code is shown below. When N receives
                                ^^^^^^^^^^^
```
This word is normally spelled as one.

## 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

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

The IANA Functions Operator has completed its review of draft-ietf-spring-nsh-sr-11. If any part of this review is inaccurate, please let us know.

The IANA Functions Operator understands that, upon approval of this document, there are two actions which we must complete.

First, in the Assigned Internet Protocol Numbers registry on the Protocol Numbers registry page located atL

https://www.iana.org/assignments/protocol-numbers/

a new registration will be made as follows:

Decimal: [ TBD-at-Registration ]
Keyword: NSH
Protocol: Network Service Header
IPv6 Extension Header: N
Reference: [ RFC-to-be ]

Second, in the SRv6 Endpoint Behaviors registry on the Segment Routing registry page located at:

https://www.iana.org/assignments/segment-routing/

a new registration is to be made as follows:

Value: [ TBD-at-Registration ]
Hex: [ TBD-at-Registration ]
Endpoint Behavior: End.NSH - NSH Segment
Reference: [ RFC-to-be ]
Change Controller: IETF

The IANA Functions Operator understands that this is the only action required to be completed upon approval of this document.

Note:  The actions 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 list of actions that will be performed.

For definitions of IANA review states, please see:

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

Thank you,

Michelle Thangtamsatid
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?

Intended status is Standards Track.
This is indicated in the front page of the draft and in the datatracker.
This seems a proper type of RFC for a document defining (in §5.1) a data plane behavior on the Service Function Forwarders (SFF) which needs to be coordinated with the Segment Routing (SR) source node.

(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:

  This document describes the integration of Network Service Header
  (NSH) and Segment Routing (SR), as well as the encapsulation format, to
  support Service Function Chaining (SFC)  while
  maintaining separation of the service and transport planes.

Working Group Summary:

WG Last Call has been copied to the SFC WG. There was relatively limited support but no controversy. The document has passed Routing and Internet directorate review.

Document Quality:

There are no implementation nor implementation plan which have been publicly shared.

Personnel:

The Document Shepherd is Bruno Decraene
The Responsible Area Director is Andrew Alston

(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.

Id nits checks.
Multiple complete readings of this document and discussions with authors on the mailing list.
Review of SPRING WG mailing list on the WG and individual draft
https://mailarchive.ietf.org/arch/browse/spring/?q=draft-ietf-spring-nsh-sr



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

More reviews would have been better but I've checked with the SFC WG chairs and this level of review is inline with other SFC documents.
I don't have concerns.

(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. An early directorate review has been requested to the Routing and Internet directorate.


(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.

No specific concern.
This solution may be useful in some scenario (both SR & NSH used). However, so far there is no implementation.

(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?

Each author has confirmed IPR disclosure on the WG mailing list.
Each contributor has confirmed IPR disclosure on the WG mailing list.
https://mailarchive.ietf.org/arch/browse/spring/?q=%22IPR%20call%20for%20draft-ietf-spring-nsh-sr%22


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

Two IPR disclosure have been filed.
https://datatracker.ietf.org/ipr/search/?submit=draft&id=draft-ietf-spring-nsh-sr

There was no WG discussion on the IPR.

(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?

WGLC was performed in the SPRING WG and copied to the SFC WG.
A fraction of the WG supports progressing this document. No objection from the rest of the WG.


(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 one has threatened an appeal or otherwise indicated extreme discontent.

(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.

Id nits complains about a non-RFC6890-compliant IPv4 addresses but it's actually a section number (4.3.1.1)


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

No such formal review.

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

Yes.

(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?

All normative references are RFCs.

(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.

Yes, there are two downward normative references:
[RFC7665]  "Service Function Chaining (SFC) Architecture". This document had already been listed as downward normative references for RFC 8300 Network Service Header (NSH)
[RFC8596]  "MPLS Transport Encapsulation for the Service Function Chaining (SFC) Network Service Header (NSH)"


(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.

Publication of this document would not change the status of any existing RFC.

(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 8126).

Both IANA sections checked.
Plus RFC 8126 section 3.1 reread.

(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.

This document does not define new IANA registry.

(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, YANG modules, etc.

This document does not use formal language.

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) for syntax and formatting validation? If there are any resulting errors or warnings, what is the justification for not fixing them at this time? Does the YANG module comply with the Network Management Datastore Architecture (NMDA) as specified in RFC8342?

This document does not contain YANG module

The following Last Call announcement was sent out (ends 2022-06-30):

From: The IESG
To: IETF-Announce
CC: andrew-ietf@liquid.tech, bruno.decraene@orange.com, draft-ietf-spring-nsh-sr@ietf.org, spring-chairs@ietf.org, spring@ietf.org
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (Integration of Network Service Header (NSH) and Segment Routing for Service Function Chaining (SFC)) to Proposed Standard


The IESG has received a request from the Source Packet Routing in Networking
WG (spring) to consider the following document: - 'Integration of Network
Service Header (NSH) and Segment Routing for
  Service Function Chaining (SFC)'
  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 2022-06-30. 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 describes the integration of the Network Service Header
  (NSH) and Segment Routing (SR), as well as encapsulation details, to
  support Service Function Chaining (SFC) in an efficient manner while
  maintaining separation of the service and transport planes as
  originally intended by the SFC architecture.

  Combining these technologies allows SR to be used for steering
  packets between Service Function Forwarders (SFF) along a given
  Service Function Path (SFP) while NSH has the responsibility for
  maintaining the integrity of the service plane, the SFC instance
  context, and any associated metadata.

  This integration demonstrates that NSH and SR can work cooperatively
  and provide a network operator with the flexibility to use whichever
  transport technology makes sense in specific areas of their network
  infrastructure while still maintaining an end-to-end service plane
  using NSH.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-spring-nsh-sr/


The following IPR Declarations may be related to this I-D:

  https://datatracker.ietf.org/ipr/4626/
  https://datatracker.ietf.org/ipr/3695/

(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?

Intended status is Standards Track.
This is indicated in the front page of the draft and in the datatracker.
This seems a proper type of RFC for a document defining (in §5.1) a data plane behavior on the Service Function Forwarders (SFF) which needs to be coordinated with the Segment Routing (SR) source node.

(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:

  This document describes the integration of Network Service Header
  (NSH) and Segment Routing (SR), as well as the encapsulation format, to
  support Service Function Chaining (SFC)  while
  maintaining separation of the service and transport planes.

Working Group Summary:

WG Last Call has been copied to the SFC WG. There was relatively limited support but no controversy. The document has passed Routing and Internet directorate review.

Document Quality:

There are no implementation nor implementation plan which have been publicly shared.

Personnel:

The Document Shepherd is Bruno Decraene
The Responsible Area Director is Martin Vigoureux

(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.

Id nits checks.
Multiple complete readings of this document and discussions with authors on the mailing list.
Review of SPRING WG mailing list on the WG and individual draft
https://mailarchive.ietf.org/arch/browse/spring/?q=draft-ietf-spring-nsh-sr



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

More reviews would have been better but I've checked with the SFC WG chairs and this level of review is inline with other SFC documents.
I don't have concerns.

(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. An early directorate review has been requested to the Routing and Internet directorate.


(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.

No specific concern.
This solution may be useful in some scenario (both SR & NSH used). However, so far there is no implementation.

(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?

Each author has confirmed IPR disclosure on the WG mailing list.
Each contributor except Syed Hassan (Cisco System, inc. shassan@cisco.com) has confirmed IPR disclosure on the WG mailing list. Even though his email seems to work, Syed never replied.
https://mailarchive.ietf.org/arch/browse/spring/?q=%22IPR%20call%20for%20draft-ietf-spring-nsh-sr%22


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

Two IPR disclosure have been filed.
https://datatracker.ietf.org/ipr/search/?submit=draft&id=draft-ietf-spring-nsh-sr

There was no WG discussion on the IPR.

(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?

WGLC was performed in the SPRING WG and copied to the SFC WG.
A fraction of the WG supports progressing this document. No objection from the rest of the WG.


(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 one has threatened an appeal or otherwise indicated extreme discontent.

(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.

Id nits complains about a non-RFC6890-compliant IPv4 addresses but it's actually a section number (4.3.1.1)


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

No such formal review.

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

Yes.

(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?

All normative references are RFCs.

(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.

Yes, there are two downward normative references:
[RFC7665]  "Service Function Chaining (SFC) Architecture". This document had already been listed as downward normative references for RFC 8300 Network Service Header (NSH)
[RFC8596]  "MPLS Transport Encapsulation for the Service Function Chaining (SFC) Network Service Header (NSH)"


(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.

Publication of this document would not change the status of any existing RFC.

(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 8126).

Both IANA sections checked.
Plus RFC 8126 section 3.1 reread.

(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.

This document does not define new IANA registry.

(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, YANG modules, etc.

This document does not use formal language.

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) for syntax and formatting validation? If there are any resulting errors or warnings, what is the justification for not fixing them at this time? Does the YANG module comply with the Network Management Datastore Architecture (NMDA) as specified in RFC8342?

This document does not contain YANG module

(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?

Intended status is Standards Track.
This is indicated in the front page of the draft and in the datatracker.
This seems a proper type of RFC for a document defining (in §5.1) a data plane behavior on the Service Function Forwarders (SFF) which needs to be coordinated with the Segment Routing (SR) source node.

(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:

  This document describes the integration of Network Service Header
  (NSH) and Segment Routing (SR), as well as the encapsulation format, to
  support Service Function Chaining (SFC)  while
  maintaining separation of the service and transport planes.

Working Group Summary:

WG Last Call has been copied to the SFC WG. There was relatively limited support but no controversy. The document has passed Routing and Internet directorate review.

Document Quality:

There are no implementation nor implementation plan which have been publicly shared.

Personnel:

The Document Shepherd is Bruno Decraene
The Responsible Area Director is Martin Vigoureux

(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.

Id nits checks.
Multiple complete readings of this document and discussions with authors on the mailing list.
Review of SPRING WG mailing list on the WG and individual draft
https://mailarchive.ietf.org/arch/browse/spring/?q=draft-ietf-spring-nsh-sr



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

More reviews would have been better but I've checked with the SFC WG chairs and this level of review is inline with other SFC documents.
I don't have concerns.

(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. An early directorate review has been requested to the Routing and Internet directorate.


(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.

No specific concern.
This solution may be useful in some scenario (both SR & NSH used). However, so far there is no implementation.

(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?

Each author has confirmed IPR disclosure on the WG mailing list.
Each contributor except Syed Hassan (Cisco System, inc. shassan@cisco.com) has confirmed IPR disclosure on the WG mailing list. Even though his email seems to work, Syed never replied.
https://mailarchive.ietf.org/arch/browse/spring/?q=%22IPR%20call%20for%20draft-ietf-spring-nsh-sr%22


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

Two IPR disclosure have been filed.
https://datatracker.ietf.org/ipr/search/?submit=draft&id=draft-ietf-spring-nsh-sr

There was no WG discussion on the IPR.

(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?

WGLC was performed in the SPRING WG and copied to the SFC WG.
A fraction of the WG supports progressing this document. No objection from the rest of the WG.


(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 one has threatened an appeal or otherwise indicated extreme discontent.

(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.

Id nits complains about a non-RFC6890-compliant IPv4 addresses but it's actually a section number (4.3.1.1)


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

No such formal review.

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

Yes.

(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?

All normative references are RFCs.

(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.

Yes, there are two downward normative references:
[RFC7665]  "Service Function Chaining (SFC) Architecture". This document had already been listed as downward normative references for RFC 8300 Network Service Header (NSH)
[RFC8596]  "MPLS Transport Encapsulation for the Service Function Chaining (SFC) Network Service Header (NSH)"


(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.

Publication of this document would not change the status of any existing RFC.

(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 8126).

Both IANA sections checked.
Plus RFC 8126 section 3.1 reread.

(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.

This document does not define new IANA registry.

(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, YANG modules, etc.

This document does not use formal language.

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) for syntax and formatting validation? If there are any resulting errors or warnings, what is the justification for not fixing them at this time? Does the YANG module comply with the Network Management Datastore Architecture (NMDA) as specified in RFC8342?

This document does not contain YANG module

Request for posting confirmation emailed to previous authors: Jim Guichard , Mohamed Boucadair , Haoyu Song , Joel Halpern , Syed Hassan , Wim Henderickx , Jeff Tantsura

Request for posting confirmation emailed to previous authors: Joel Halpern , Wim Henderickx , Jim Guichard , Mohamed Boucadair , Jeff Tantsura , Haoyu Song , Syed Hassan