The Application of the Path Computation Element Architecture to the Determination of a Sequence of Domains in MPLS and GMPLS
draft-ietf-pce-hierarchy-fwk-05

[Ballot comment]
I have no problems with the publication of this document and only have the following comment.

- The discussion of objective functions seems incomplete.  Section 4.1 talks about deriving an optimal end-to-end path based on an OF or set of OFs.  However, in talking with one of the authors, it became clear that the same OF (or set of OFs) may not be applied across all domains given local policy within a domain and/or contractual arrangements between domains.  I think it would be useful to add some discussion of these types of issues and the impact they will have on the optimality of the computed path.

IANA has reviewed draft-ietf-pce-hierarchy-fwk-04, which is currently
in Last Call, and has the following comments:

IANA understands that, upon approval of this document, there are no
IANA Actions that need completion.

The following Last Call announcement was sent out:

From: The IESG
To: IETF-Announce
CC:
Reply-To: ietf@ietf.org
Subject: Last Call:  (The Application of the Path Computation Element Architecture to the Determination of a Sequence of Domains in MPLS and GMPLS) to Informational RFC


The IESG has received a request from the Path Computation Element WG
(pce) to consider the following document:
- 'The Application of the Path Computation Element Architecture to the
  Determination of a Sequence of Domains in MPLS and GMPLS'
  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 2012-08-24. 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


  Computing optimum routes for Label Switched Paths (LSPs) across
  multiple domains in MPLS Traffic Engineering (MPLS-TE) and GMPLS
  networks presents a problem because no single point of path
  computation is aware of all of the links and resources in each
  domain. A solution may be achieved using the Path Computation
  Element (PCE) architecture.

  Where the sequence of domains is known a priori, various techniques
  can be employed to derive an optimum path. If the domains are
  simply-connected, or if the preferred points of interconnection are
  also known, the Per-Domain Path Computation technique can be used.
  Where there are multiple connections between domains and there is
  no preference for the choice of points of interconnection, the
  Backward Recursive Path Computation Procedure (BRPC) can be used to
  derive an optimal path.

  This document examines techniques to establish the optimum path when
  the sequence of domains is not known in advance. The document
  shows how the PCE architecture can be extended to allow the optimum
  sequence of domains to be selected, and the optimum end-to-end path
  to be derived through the use of a hierarchical relationship between
  domains.




The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-pce-hierarchy-fwk/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-pce-hierarchy-fwk/ballot/


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

(1) What type of RFC is being requested?
-> Informational.

Why is this the proper type of RFC?
-> Because it extends the architecture and does not specify any protocol.

Is this type of RFC indicated in the title page header?
-> Yes.


(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

Computing optimum routes for Label Switched Paths (LSPs) across
multiple domains in MPLS Traffic Engineering (MPLS-TE) and GMPLS
networks presents a problem because no single point of path
computation is aware of all of the links and resources in each
domain. A solution may be achieved using the Path Computation
Element (PCE) architecture.

Where the sequence of domains is known a priori, various techniques
can be employed to derive an optimum path. If the domains are
simply-connected, or if the preferred points of interconnection are
also known, the Per-Domain Path Computation technique can be used.
Where there are multiple connections between domains and there is
no preference for the choice of points of interconnection, the
Backward Recursive Path Computation Procedure (BRPC) can be used to
derive an optimal path.

This document examines techniques to establish the optimum path when
the sequence of domains is not known in advance. The document
shows how the PCE architecture can be extended to allow the optimum
sequence of domains to be selected, and the optimum end-to-end path
to be derived through the use of a hierarchical relationship between
domains.


Working Group Summary
Was there anything in WG process that is worth noting?
-> No.

For example, was there controversy about particular points or were there
decisions where the consensus was particularly rough?
-> No.

Document Quality
Are there existing implementations of the protocol? Have a
significant number of vendors indicated their plan to implement the
specification?
-> N/A.

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?
-> No.

If there was a MIB Doctor, Media Type or other expert review, what was
its course (briefly)?
-> N/A.

In the case of a Media Type review, on what date was the request posted?
-> N/A.

Personnel
Who is the Document Shepherd?
-> Julien Meuric.

Who is the Responsible Area Director?
-> Stewart Bryant.


(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 has good support, is clearly written and thus 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.


(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 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.
-> The 4 identified authors have confirmed.


(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 disclosure.


(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?
-> Good support; an I-D proposing corresponding protocol extensions exists.


(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.
-> OK.


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


(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.


(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).
-> No IANA action requested, consistently with the body of 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.
-> N/A.


(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.
-> N/A.