Gap Analysis for Operating IPv6-Only MPLS Networks
draft-ietf-mpls-ipv6-only-gap-04

[Ballot comment]
section 1 2 3 are basically all introduction. it seems like that could be streamlined considerably and therefore ready more easily but it doesn't really impact the rest of the document.

[Ballot comment]
Sections 1 and 2 duplicate a great deal of text.  Please take the time to edit this down so that you aren't saying the same thing three paragraphs apart.

3.2.1:

  While LDP was
  designed to use an IPv4 or dual-stack IP network, it has a number of
  deficiencies that prohibit it from working in an IPv6-only network.

I think the word you're looking for here is "prevent," not "prohibit."

Aside from the above carping, this is a good document.  Thanks for doing it!

[Ballot comment]
This draft was pleasantly easy for a nonspecialist to read, most of the time. I struggled with these sections:

I lack understanding on this one:

3.3.3.  MPLS Transport Profile (MPLS-TP)

  MPLS-TP does not require IP (see section 2 of RFC 5921 [RFC5921]) and
  should not be affected by operation on an IPv6-only network.
  Therefore this is considered out of scope for this document, but is
  included for completeness.

  Although not required, MPLS-TP can use IP.  One such example is
  included in Section 3.2.6, where MPLS-TP identifiers can be derived
  from valid IPv4 addresses.

  Gap: None.

So, I would read this as saying that MPLS-TP identifiers can be derived from valid IP addresses, whether v4 or v6, if there's no gap, but I'm extrapolating beyond what the text says. You might want to clarify whether "None" is based on the first paragraph (doesn't require IP at all), or also on the second one (can use either version of IP).

I couldn't parse this one:

3.4.2.  Label Switched Path Ping (LSP Ping)

  Gap: Major.  LSP ping uses IPv4-mapped IPv6 addresses, IP version
  mismatches may cause dropped messages, unclear mapping from LSR
  Router ID to Downstream IP Address.

Is this saying IP version mismatches may cause unclear mapping? This might be as simple as s/messages, unclear/messages and unclear/, but I'm guessing.

This one's worse than section 3.3.3.  MPLS Transport Profile (MPLS-TP):

3.4.5.  MPLS Transport Profile (MPLS-TP) OAM

  As with MPLS-TP, MPLS-TP OAM RFC 6371 [RFC6371] does not require IP
  or existing MPLS OAM functions, and should not be affected by
  operation on an IPv6-only network.  Therefore, this is out of scope
  for this document, but is included for completeness.  Although not
  required, MPLS-TP can use IP.

  Gap: None.

Is this saying that MPLS-TP can use IPv6 and there's no gap, or is it saying that there's no gap because IP isn't required, and just helpfully pointing out that there may or may not be a gap for IPv6, but the reader will have to figure that out?

Nit: s/Identifed/Identified/, I think.

I agree with Richard's suggestion for a summary early in the document.

[Ballot comment]
It would be helpful if you could summarize the findings of this analysis in the Abstract.  For example:

"While the MPLS data plane fully supports carriage of IPv6 packets, support for IPv6 among MPLS management protocols is mixed, with some protocols having major gaps.  For most major gaps, however, work is in progress to upgrade the relevant protocols."

[Ballot comment]
I submit that a good number of the references really are normative, in that understanding them is necessary in order to understand this document.  I'd like to see the authors sort that out, and make an appropriate split in the references, so readers can know which ones truly do just add extra detail (informative), and which provide necessary background (normative).  That said, I don't consider that important enough to this document to block on it, so this is a non-blocking comment.  I understand that the working group prefers not to do this for this document.  Thanks for considering the comment.

[Ballot discuss]
This is a DISCUSS in the truest sense: I'd like to discuss a question with the shepherd and/or AD, and I fully expect to resolve the question satisfactorily from that.

The first thing I wondered was why this shouldn't be something maintained in a place other than an RFC, and I found that covered well in the shepherd writeup. Thanks for that!

What I continue to wonder is whether, in having that discussion, the working group considered what the likelihood is of discovering more gaps as they (and other working groups) work on dealing with these.  If so, I wonder what the working group's plan is for documenting those.

[Ballot comment]
I submit that a good number of the references really are normative, in that understanding them is necessary in order to understand this document.  I'd like to see the authors sort that out, and make an appropriate split in the references, so readers can know which ones truly do just add extra detail (informative), and which provide necessary background (normative).  That said, I don't consider that important enough to this document to block on it, so this is a non-blocking comment.  Please consider doing this, but there is no need to respond to me about it.  Thanks.

Minor edits from reviews by me and Tobias Gondrom need a new revision.

The document is on the telechat agenda for 11/25 so a new revision well before that date would be welcomed.

If you produce the revision before the pre-Hawaii lockdown is lifted, please mail it to me and I will get it posted.

IESG/Authors/WG Chairs:

IANA has reviewed draft-ietf-mpls-ipv6-only-gap-02, which is currently in Last Call, and has the following comments:

We understand that this document doesn't require any IANA actions.

While it is helpful for the IANA Considerations section of the document to remain in place upon publication, if the authors prefer to remove it, IANA doesn't object.

If this assessment is not accurate, please respond as soon as possible.

The following Last Call announcement was sent out:

From: The IESG
To: IETF-Announce
CC:
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Gap Analysis for Operating IPv6-only MPLS Networks) to Informational RFC


The IESG has received a request from the Multiprotocol Label Switching WG
(mpls) to consider the following document:
- 'Gap Analysis for Operating IPv6-only MPLS Networks'
  as Informational RFC

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 2014-10-27. 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 reviews the Multiprotocol Label Switching (MPLS)
  protocol suite in the context of IPv6 and identifies gaps that must
  be addressed in order to allow MPLS-related protocols and
  applications to be used with IPv6-only networks.  This document is
  not intended to highlight a particular vendor's implementation (or
  lack thereof) in the context of IPv6-only MPLS functionality, but
  rather to focus on gaps in the standards defining the MPLS suite.

The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-mpls-ipv6-only-gap/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-mpls-ipv6-only-gap/ballot/


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

AD review
==========

Thank you for writing this document. I think it is an important
piece of work and I will send it to IETF last call.

Set out below you will find comments from my AD review. I don't think
any is blocking or requires specific updates before IETF last call,
but I would be glad if you would address them along the way or send me
email to discuss them.

Thanks for the work,
Adrian

===

The choice of documents to reference for the different control plane
sections related to RSVP-TE seemed idiosyncratic to me. For example,
the GMPLS section (3.2.6) references RFC 4558, RFC 4990, and RFC 6370
all of which certainly are GMPLS documents, but there is no reference
to the base GMPLS protocol documents (RFC 3471 and 3473) nor a back
pointer to section 3.2.3. Similarly, the PCE section (3.2.4)
  [Incidentally, this has a really weird section title! Where
  did "controller" come from, and why is the section named
  after a component and not a protocol (PCEP)?]
includes references to a number of protocol extensions, but neither
3.2.3 nor 3.2.6 seem to care about the detailed protocol extensions to
RSVP-TE.

This issue isn't in any way a show-stopper. It just makes me wonder
about the precision of the survey wrt RSVP-TE given the amount of
detail in some of the other sections.

---

Section 3.3.3 has

  MPLS-TP does not require IP (see section 2 of RFC 5921 [RFC5921]) and
  should not be affected by operation on an IPv6-only network.
  Therefore this is considered out of scope for this document, but is
  included for completeness.

This is odd! Just because MPLS-TP does not require the presence of IP,
does not mean it might not be there and used. Indeed, in Section 3.2.6
you reference RFC6370 and use it to state a minor GMPLS deficiency.
Yet 6370 is an MPLS-TP document! It is all about how identifiers are
generated and used in MPLS-TP networks, and (as the RFC says) in
documents where IP is present, the identifiers can be generated using the
local IP addresses.

Similarly, section 3.4.5 is a little ambitious in its claims of zero
dependence on IP since identifiers play an important part in MPLS-TP
OAM.

This issue doesn't change the end result (although I would probably move
the paragraph on 6370 from section 3.2.6 to this section.

---

Throughout, you should probably refer to "MIB modules" not "MIBs"

---

I am sceptical about section 3.5. Earlier in the document you have
mentioned the fact that RFC 4990 explains how to use existing MIB
modules with IPv6 addresses, but you don't mention that RFC here.
Conversely, you do mention an individual I-D that does not (yet?)
have working group support to fix a problem that it is not clear is
the problem that needs to be fixed in a way that seems to me to be
wrong.

---

I never object to my name being spelled correctly :-)

  The MPLS Working Group request that

          Gap Analysis for Operating IPv6-only MPLS Networks
                    draft-ietf-mpls-ipv6-only-gap-02

Is published as as an Informational RFC.

(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?

  We request that the document is published as an Informational RFC.
  This document is a "gap-analysis" it looks at what is missing if you want
  run MPLS in IPv6 only networks. The document does not not specify any
  protocol or define codepoints. This is pretty much a typical informational
  RFC.

(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 reviews the MPLS protocol suite in the context of IPv6
  and identifies gaps that must be addressed in order to allow MPLS-related
  protocols and applications to be used with IPv6-only networks.  This
  document is not intended to highlight a particular vendor's implementation
  (or lack thereof) in the context of IPv6-only MPLS functionality, but
  rather to focus on gaps in the standards defining the MPLS suite.

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?

  There is a good support in the working group for this draft, and it is needed
  to figure out the gaps that needs to be filled to run MPLS in a IPv6 only
  network; the draft point to several issues that needs to be addressed.

  There were comments during wglc that has been addressed.

  This document were one of the first documents that did go through the new
  Quality Assurance(QA)  that is started for Rtg Area documents. This review
  was done in parallel with the wglc. The QA review concluded that this is a
  very useful document of good quality.  There were a set  of technical and
  editorial comments that were addressed in the process to resolve the wglc
  comments.
  The QA also resulted in a comment that said that this document is a gap
  analysis and as such gives a description at one point in time, and ask if
  this should be published as a living document instead.

  This was discussed bu the working group and the working group chairs
  called consensus in a mail to the working group.

  http://www.ietf.org/mail-archive/web/mpls/current/msg12752.html

  Saying:
  "The working group chairs find that the working group have consensus to
    move ahead with the document (version -02) as it has been updated after
    the wglc and reviews.

    The value in having  the document publish by far outweigh not having it
    published. The benefits in moving the reference to an appendix (or
    removing them) is not comparable to have easily at hand when reading
    the document."

  That  said the wg chairs are agreeable to, as soon as the RFC is published
  start following the process of filling the MPLS/IPv6 gaps, we believe that this
  eventually cover more than the MPLS specification and that it is a job that
  will be relevant for the entire rtg area.


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, 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?

  This is an informational and a gap analysis document, no implementations
  are expected. On the other hand there are already activities and drafts
  looks to filling the gaps identified in the document.

Personnel

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

  Loa Andersson is the Document Shepherd.
  Adrian Farrel is the Responsible Area Director.

(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 reviewed the entire document two times
  once preparing the MPLS-RT review/adoption poll and once preparing the
  wglc.

  The document think this version of the document is ready to be published
  as an Informational RFC.

  However, we have a small set of smaller comments that we are holding waiting
  for the AD evaluation, this does not change the opinion that the document is
  ready for publication.
 

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

  No such 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 such reviews needed.

(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 such concerns.

(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 of the authors has stated on the MPLS wg mailing list that they
  are unaware of any IPRs.

(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 disclosures.

(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? 

(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.)

  This document is well discussed on the mailing list and at wg meetings,
  both as an individual document, after it has been accepted as a wg
  document and in the consensus process following the rtg area directorate
  review.

(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.

  Two of the referenced document has expired, no other nits reported.

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

  No such reviews necessary.

(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?

(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.

  This document only have informative references.

(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.

  There are no status changes of other documents when this document
  is published.


(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).

  There are no IANA considerations.

(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 new registries that will need Expert Review.

(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 such formal reviews.