Deterministic Networking (DetNet) Data Plane: IEEE 802.1 Time-Sensitive Networking over MPLS
draft-ietf-detnet-tsn-vpn-over-mpls-07

[Ballot comment]
In Section 2.2, you define "CW", but the term used in the document is actually "d-CW".  "MPLS-TP", though defined here as well, is not present elsewhere in the document.

[Ballot comment]
While I could easily imagine a document like this being an Informational
document, I don't object to the requested Proposed Standard status.
(FWIW, the only strong new normative requirement I remember seeing is
that aggregation of TSN flows into DetNet flows "SHALL be supported".)

I didn't take the time to sign up for an IEEE account to use the "IEEE Get"
program and pull the external references, but what is described from them
seems to make sense just from the standalone descriptions here.

I just have a couple of (barely) substantive comments, followed by some
editorial/nit-level remarks that need no reply.

Section 7

Given that this documents calls for flooding of TSN frames in some
scenarios, it seems like a caution against the risk of L2 loops would
not be out of place (though I would hope no one would be surprised about
it).

Section 10.2

I think the IEEE references need to be normative; we say that DetNet
Edge Node acts as a TSN entity and so compliance with the TSN specs is
mandatory.

And the editorial stuff:

Section 4.1

                                                        MPLS DetNet
  nodes and transit nodes include DetNet forwarding sub-layer
  functions, support for notably explicit routes, and resources
  allocation to eliminate (or reduce) congestion loss and jitter.

nits: I think this is better as "notably, support for explicit routes
and resource allocation to eliminate (or reduce) congestion loss and
jitter".

Section 4.2

My understanding is that each column in figure 3 is intended to
represent a distinct TSN Stream/App-flow; it might be useful to confirm
that somewhere (e.g., with a note about showing three example flows in
the figure).

  In the figure, "Application" indicates the application payload
  carried by the TSN network.  "MPLS App-Flow" indicates that the TSN
  Stream is the payload from the perspective of the DetNet MPLS data
  plane defined in [RFC8964].  [...]

nit: the figure seems to say "App-Flow for MPLS" rather than the "MPLS
App-Flow" in the quoted prose.

Section 5

  Description of Edge Nodes procedures and functions for TSN over
  DetNet MPLS scenario follows the concept of [RFC3985] and covers the
  Edge Nodes components shown on Figure 1.  In this section the
  following procedures of DetNet Edge Nodes are described:

some nits here; maybe
NEW:
> The description of Edge Node procedures and functions for TSN over
> DetNet MPLS scenarios follows the concepts from [RFC3985], and covers
> the Edge Node components shown in Figure 1.  In this section the
> following procedures of DetNet Edge Nodes are described:

Section 5.1

  TSN specific functions are executed on the data received by the
  DetNet Edge Node from the connected CE before forwarded to connected
  CE(s) or presentation to the DetNet Service Proxy function for
  transmission across the DetNet domain.  [...]

nit: there's a type of speech mismatch between "forwarded" and
"presentation" (and "forwarded" would need to be "being forwarded" in
order to be grammatical), so the list doesn't have a parallel structure.
I'd suggest "before being forwarded to connected CE(s) or presented to
the DetNet Service Proxy function", but there are plenty of other valid
options.

  When a TSN entity of the PE receives a packet from the DetNet Service
  Proxy, it first checks via Stream Identification (see Clause 6. of
  IEEE 802.1CB [IEEE8021CB] and IEEE P802.1CBdb [IEEEP8021CBdb])
  whether the packet belongs to a configured TSN Stream.  If no Stream
  ID is matched, then packet is dropped.  [...]

nit: s/then packet/then the packet/

Section 5.2

  When a DetNet Service Proxy receives a packet from the TSN Entity it
  MUST check whether such an App-flow is present in its mapping table.
  If present it associates the internal DetNet flow-ID to the packet
  and MUST forward it to the DetNet Service and Forwarding sub-layers.
  If no matching statement is present it MUST drop the packet.

(nit) this seems to be the only place I could find that uses the term
"statement" to refer to an entry in the DetNet flow mapping table; I'd
suggest using a phrasing like "if no match is found".

              The management or control function that provisions flow
  mapping SHALL ensure that adequate resources are allocated and
  configured to provide proper service requirements of the mapped
  flows.

nit: I think we'd say "provider proper service that meets the
requirements" or "to fulfil the service requirements"; just "providing
service requirements" doesn't seem to match up to the intended meaning.

  Due to the (intentional) similarities of the DetNet PREOF and TSN
  FRER functions service protection function interworking is possible
  between the TSN and the DetNet domains.  Such service protection
  interworking scenarios MAY require to copy sequence number fields
  from TSN (L2) to PW (MPLS) encapsulation.  However, such interworking
  is out-of-scope in this document and left for further study.

This feels more like a descriptive "may" or "might" than a normative
"MAY" to me.

Section 5.3

  sequence number are not valid outside the DetNet network.  MPLS
  (DetNet) Edge node terminates all related information elements
  encoded in the MPLS labels.

nit: missing article for "MPLS Edge node", but I'd suggest converting to
the plural "Edge nodes terminate" to avoid the issue.

Section 6

                        For example, it may be not trivial to locate
  the egress point/interface of a TSN Streams with a multicast
  destination MAC address. 

nit: singular/plural mismatch "a TSN Streams" (it looks like using the
singular "Stream" is the minimal change to resolve).

[Ballot comment]
The following references should be Normative: I-D.ietf-detnet-security, IEEE8021CB, IEEE8021Q, IEEEP8021CBdb, RFC8655 and RFC8938.

Some of these references describe TSN, an understanding which is required to execute normative actions.  Others represent the architecture, framework, and security considerations for DetNet -- note that other data plane documents use them normatively as well.

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

Please find below some non-blocking COMMENT points (but replies would be appreciated).

I hope that this helps to improve the document,

Regards,

-éric

== COMMENTS ==

Mainly out of curiosity, why is draft-ietf-detnet-tsn-vpn-over-mpls standard track while draft-ietf-detnet-mpls-over-tsn is informational ? (and I understand that they are dual protocols TSNoMPLS vs. MPLSoTSN)

-- Abstract --
Please expand TSN as it is not a RFC Editor well-known acronym.

[Ballot comment]
[[ comments ]]

* I know that RFC 8964 doesn't have any text about MTU and fragmentation
  considerations, but RFC 3985 does.

  The layering diagram in section 4.2 made me thing it might be worth
  either adding some text or pointing to some text elsewhere that
  advises the DetNet network operator to make sure that all the DetNet
  encapsulation overhead plus the MTU of the TSN not exceed the DetNet
  network's MTU, otherwise fragmentation considerations arise.

  Even a reference to RFC 3985 section 5.3 might be enough to remind the
  reader of these additional considerations.

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

The IANA Functions Operator has reviewed draft-ietf-detnet-tsn-vpn-over-mpls-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
Senior IANA Services Specialist

The following Last Call announcement was sent out (ends 2021-02-05):

From: The IESG
To: IETF-Announce
CC: Lou Berger , db3546@att.com, detnet-chairs@ietf.org, detnet@ietf.org, draft-ietf-detnet-tsn-vpn-over-mpls@ietf.org, lberger@labn.net
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (DetNet Data Plane: IEEE 802.1 Time Sensitive Networking over MPLS) to Proposed Standard


The IESG has received a request from the Deterministic Networking WG (detnet)
to consider the following document: - 'DetNet Data Plane: IEEE 802.1 Time
Sensitive Networking over MPLS'
  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 2021-02-05. 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 specifies the Deterministic Networking data plane when
  TSN networks are interconnected over a DetNet MPLS Network.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-detnet-tsn-vpn-over-mpls/



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

> As required by RFC 4858, this is the current template for the Document
> Shepherd Write-Up. Changes are expected over time.
> This version is dated 1 November 2019.


> (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 document defines behaviors requried to interoperability of
different implementations supporting TSN networks interconnected
over a DetNet MPLS Network.

> Technical Summary:
>
> Relevant content can frequently be found in the abstract and/or
> introduction of the document. If not, this may be an indication that
> there are deficiencies in the abstract or introduction.


This document describes specifies the data-plane aspects of how IEEE
802.1 TSN networks are interconnected over a DetNet MPLS Network.

> Working Group Summary:
>
> Was there anything in WG process that is worth noting? For example, was
> there controversy about particular points or were there decisions where
> the consensus was particularly rough?

Nothing notable.

> Document Quality:
> Are there existing implementations of the protocol? Have a significant
> number of vendors indicated their plan to implement the specification?
> 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, YANG 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?

While there seems to be interest in this speficiations from multiple
vendors, there are no publicly known implementations of this
specification.  There are no specific reviews worth noting.

> Personnel:

> Who is the Document Shepherd?
Lou Berger

> Who is the Responsible Area Director?
Deborah Brungard

> (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.

The Shepherd reviewed this document as it progressed through the WG as
well as part of Last Call.  All significant comments have been resolved.

> (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.

No concerns.  The document basically says use other standards in a
specific way to ensure interoperability.  There's slightly more left for
further documents than I would have hoped, but the approach of defining
data-plane first is reasonable.

> (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, see
https://mailarchive.ietf.org/arch/msg/detnet/aORVwYHMU61mZ-xyUmWAqU4NpGM/

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

No IPR has been disclosed.

> (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?

I think the document has good support from the narrow set of WG
participants interested in this problem space (TSN over MPLS).

> (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.

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.

Idnits shows unused references that should be removed in the next revision.

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

N/A. YANG support will be done speperatley based on other work in the WG.

> (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?

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.

No, N/A.

> (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).

No requests are made in the document.

> (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, YANG modules,
> etc.

N/A

> (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?

There are no yang modules.

> As required by RFC 4858, this is the current template for the Document
> Shepherd Write-Up. Changes are expected over time.
> This version is dated 1 November 2019.


> (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 document defines behaviors requried to interoperability of
different implementations supporting TSN networks interconnected
over a DetNet MPLS Network.

> Technical Summary:
>
> Relevant content can frequently be found in the abstract and/or
> introduction of the document. If not, this may be an indication that
> there are deficiencies in the abstract or introduction.


This document describes specifies the data-plane aspects of how IEEE
802.1 TSN networks are interconnected over a DetNet MPLS Network.

> Working Group Summary:
>
> Was there anything in WG process that is worth noting? For example, was
> there controversy about particular points or were there decisions where
> the consensus was particularly rough?

Nothing notable.

> Document Quality:
> Are there existing implementations of the protocol? Have a significant
> number of vendors indicated their plan to implement the specification?
> 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, YANG 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?

While there seems to be interest in this speficiations from multiple
vendors, there are no publicly known implementations of this
specification.  There are no specific reviews worth noting.

> Personnel:

> Who is the Document Shepherd?
Lou Berger

> Who is the Responsible Area Director?
Deborah Brungard

> (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.

The Shepherd reviewed this document as it progressed through the WG as
well as part of Last Call.  All significant comments have been resolved.

> (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.

No concerns.  The document basically says use other standards in a
specific way to ensure interoperability.  There's slightly more left for
further documents than I would have hoped, but the approach of defining
data-plane first is reasonable.

> (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, see
https://mailarchive.ietf.org/arch/msg/detnet/aORVwYHMU61mZ-xyUmWAqU4NpGM/

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

No IPR has been disclosed.

> (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?

I think the document has good support from the narrow set of WG
participants interested in this problem space (TSN over MPLS).

> (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.

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.

Idnits shows unused references that should be removed in the next revision.

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

N/A. YANG support will be done speperatley based on other work in the WG.

> (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?

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.

No, N/A.

> (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).

No requests are made in the document.

> (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, YANG modules,
> etc.

N/A

> (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?

There are no yang modules.