Extensions to BGP-Signaled Pseudowires to Support Flow-Aware Transport Labels
draft-ietf-bess-fat-pw-bgp-04

[Ballot comment]
Is there a race condition here when an endpoint changes its R bit? Like it will temporarily get packets in the wrong state, right? Problem?

I agree with Ben about the security considerations section. One or two more sentence should suffice.

[Ballot comment]
There are a couple of instances of lower-case "should" that do not seem to be intented as 2119 keywords. Please consider using the boilerplate from RFC 8174 rather than 2119.

The security considerations could use more explanation. Please describe why the new elements and procedures in this draft do not add new security considerations.

[Ballot comment]
Thanks for the work on this document. I have two very small editorial nits:

> Abstract
>
>  This draft defines protocol extensions required to synchronize flow
>  label states among PEs when using the BGP-based signaling procedures.

Please expand "PE".

§3:

>  A PE MAY support the configuration of the flow label (T and R bits)
>  on a per-service (e.g.  VPLS VFI) basis.

Please add a comma after "e.g."

[Ballot comment]
I would be really happy if the document could say lightly more about how flow labels are supposed to be assigned. Is the assumption that all packets of an TCP flow get the same flow label assigned?

Just a comment, no action required: Given there are only 4 unsigned bits left and the registry policy is "IETF review", I actually don't think a registry is necessarily needed. The remaining bits could just be assigned by additional RFCs that update RFC4761. 

Some nits, minor comments:

1) sec 1: Please spell out "ASBR"

2) sec 3: "a PE sending a Control Flags field with T = 1 and
  receiving a Control Flags field with R = 1 MUST include a flow label
  in the Pseudowire packet."
  Must this be a MUST or could this be a SHOULD?

3) In sec 2 there is this text:
"the remaining bits, designated Z, MUST
  be set to zero when sending and MUST be ignored when receiving this
  Extended Community."
In the IANA Consideration section there is this text:
"As per [RFC4761] and this document, the remaining bits are
  unassigned, and MUST be set to zero when sending and MUST be ignored
  when receiving the Layer2 Info Extended Community."

I think the text in section 2 is actually incorrect because it should not talked about the bits that are marked Z but rather about bits that are not assigned in the newly created registry because otherwise you'd need to update this RFC (and RFC4761) every time you assign a new bit.

Further I don't think this need to be mentioned in the IANA section and should only be correctly specified in section 2. Except you would like IANA to note this on the registration page but then you should say that...

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

The IANA Services Operator has completed its review of draft-ietf-bess-fat-pw-bgp-03. If any part of this review is inaccurate, please let us know.

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

A new registry is to be created called the Layer2 Info Extended Community Control Flags Bit Vector" registry. The new registry will be located on the
Border Gateway Protocol (BGP) Extended Communities registry page located at:

https://www.iana.org/assignments/bgp-extended-communities/

The new registry will have a registration policy of IETF Review as defined in RFC 8126.

There are initial registrations in the new registry as follows:

Value Name Reference
----- -------------------------------- --------------
S Sequenced delivery of frames RFC4761
C Presence of a Control Word RFC4761
T Request to send a flow label [ RFC-to-be ]
R Ability to receive a flow label [ RFC-to-be ]

The IANA Services 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 only to confirm the list of actions that will be performed.



Thank you,

Sabrina Tanamal
Senior IANA Services Specialist

The following Last Call announcement was sent out (ends 2018-02-09):

From: The IESG
To: IETF-Announce
CC: martin.vigoureux@nokia.com, bess-chairs@ietf.org, draft-ietf-bess-fat-pw-bgp@ietf.org, bess@ietf.org, aretana.ietf@gmail.com
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Extensions to BGP Signaled Pseudowires to support Flow-Aware Transport Labels) to Proposed Standard


The IESG has received a request from the BGP Enabled ServiceS WG (bess) to
consider the following document: - 'Extensions to BGP Signaled Pseudowires to
support Flow-Aware Transport
  Labels'
  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 2018-02-09. 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 draft defines protocol extensions required to synchronize flow
  label states among PEs when using the BGP-based signaling procedures.
  These protocol extensions are equally applicable to point-to-point
  Layer2 Virtual Private Networks (L2VPNs). This draft updates RFC 4761
  by defining new flags in the Control Flags field of the Layer2 Info
  Extended Community.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-bess-fat-pw-bgp/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-bess-fat-pw-bgp/ballot/


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

=== AD Review of draft-ietf-bess-fat-pw-bgp-03 ===
https://mailarchive.ietf.org/arch/msg/bess/l-AHEbwdpeEetcAQEmHqdiBtIFA/?qid=562d42501b62f57d80bafc9dde2a742f

Dear authors:

I just finished reading this document.  Thank you for a well written and
straight forward document!!

I have some comments (see below) that I think are easy to address.  I am
then starting the IETF Last Call.

Thanks!

Alvaro.


Major:

M1. All the rfc2119 keywords in this text should not be capitalized because
they are part of an example:

  For example, a PE part of a VPLS and with a local T = 1,
  MUST only transmit traffic with a flow label to those peers that
  signaled R = 1.  And if the same PE has local R = 1, it MUST only
  expect to receive traffic with a flow label from peers with T = 1.
  Any other traffic MUST NOT have a flow label.


M2. Security Considerations: I agree that there are no new issues.
However, please also point to rfc4761 and any other document that defines
the base functionality being modified here.


Minor:

P1. "This draft introduces an OPTIONAL mode of operation..."  There's no
need for "OPTIONAL" to be Normative in this sentence since it is just
describing what it is, not specifying behavior.  s/OPTIONAL/optional


P2. The new registry has a policy of "IETF Review", which basically means
that any RFC (not just Standards Track RFCs) can use the bits in the
registry.  I ask because there are only 4 bits left.  Note that I'm not
asking you to necessarily change the policy...just pointing it out.


P3. "T  When the bit value is 1, the PE is requesting the ability..."  Did
you mean "announce the ability" instead?


P4. s/NUST NOT/MUST NOT


P5. References:  I think these can be Informative: rfc4385, rfc8077, rfc4928

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 24 February 2012.

(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 is being requested. This is indicated in the header.
This is consistent with the body of the Document which specifies protocol extensions.

(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 draft defines protocol extensions required to synchronize flow
  label states among PEs when using the BGP-based signaling procedures.
  These protocol extensions are equally applicable to point-to-point
  Layer2 Virtual Private Networks (L2VPNs). This draft updates RFC 4761
  by defining new flags in the Control Flags field of the Layer2 Info
  Extended Community.

Working Group Summary
  The WG supports the publication of this Document as a Proposed Standard RFC.
 
Document Quality
  At least one implementation exists. The Document is fairly simple and quite well written.

Personnel
  Martin Vigoureux is the Document Shepherd
  Alvaro Retana 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.

  The Document Shepherd has done an in-depth review which lead to reasonably important clarifications, including concerning the IANA section.

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

  No concern.

(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 portion of the Document needs any particular review.

(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 concern.

(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.

  All authors and Contributors have stated that they are not aware of any undisclosed IPR which would relate to this Document.

(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 against this Document.

(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?

  The consensus is solid.

(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 such situation.

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

  ID-nits result is clean.

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

  No formal review is required.

(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.

  No Downward Reference.

(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.

  Yes, this Document updates RFC 4761. This is clearly indicated in the Header and in the abstract.
  This is driven by the fact that this Document uses bits of a bit vector defined in RFC 4761 but that
  RFC did not ask IANA to create a registry for this bit vector. The Document Shepherd has considered
  that the use of additional bits was a valid reason for creating a registry and more generally to update
  RFC 4761.

(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).

  The Document has reviewed the IANA section following the RFC8126 guidelines.
  These are met:
      The codepoints requests are consistent with the body of the Document.
      The initial allocations of the new registry are clearly identified.
      The allocation policy is specified.
      A name is proposed for the registry.
      The location of the registry is indicated.

(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.

  No Expert Review based registry is requested.

(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.

  no automatic checks required.