Performance-Based Path Selection for Explicitly Routed Label Switched Paths (LSPs) Using TE Metric Extensions
draft-ietf-teas-te-express-path-05

> 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)?

Informational

> Why is this the proper type of RFC? 

Document describes how an implementation my use TE information and does
not define any protocol related formats and behaviors.

> 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
>
>  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 how to use network performance data, such as
is advertised via the OSPF and ISIS TE metric extensions (defined in
other RFCs) to perform path selection based on network performance
criteria.

> 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?

This document moved from to the TEAS WGs as part of the routing WG
changes.  This document has been fairly noncontroversial.

>
> 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?

The extensions defined in this document are compatible with earlier
implementations.  While there have been no public statements on
implementation, the authors are from multiple vendors, and
implementation is expected - or may even already exist.

> 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 Document Shepherd has reviewed the document as part of an extended
WG last calls.  The Shepherd believes this 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.

> (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?

No.

> If so, describe the review that took place.

N/A.

>
> (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 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.

Yes, see thread at
http://www.ietf.org/mail-archive/web/teas/current/msg00424.html

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

OLD: No IPR disclosed.
NEW:  IPR disclosed, see https://datatracker.ietf.org/ipr/2200/

Note that per the authors:
http://www.ietf.org/mail-archive/web/teas/current/msg00448.html
> I'm not aware of any IPR that applies on this draft.
>
> IPR related to TLVs introduced in draft-ietf-isis-te-metric-extensions and RFC7471 have been disclosed already in compliance with IPR rules.
>


> (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? 

Solid among those who are interested. "strong concurrence of a few
individuals, with others being silent" is a reasonable
characterization.

> (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 discontent seen.

>
> (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.

The document passes ID nits.

>
> (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).

The IANA section was fully reviewed by the document shepherd and is
appropriate for an Informational draft.


> (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, etc.

N/A

[Ballot comment]
Robert Spark's Gen-ART review comment should be taken into account:

This document is all about considerations. Specifically, it discusses what to consider if you were to build a path computation function that uses the kind of information you get from the TE metric extensions in RFC7471 and draft-ietf-isis-te-metric-extensions. It does not appear to be requirements for standardization work - rather, it is information for operators to use when building functions that don't necessarily need standardization.

However, it looks as if the document may have once contemplated actually specifying a path computation function, and has legacy text from that thought?

The abstract says "This specification uses network performance data ... to perform such path selections." But this document doesn't perform such path selections (or specify how to do them).

Section 1.1 says "The following are the requirements that motivate this solution." But this draft doesn't actually specify a "solution". It discusses what to consider if you were to build a path computation function. Could this be framed as a set of goals to keep in mind while building your own such function?

The third paragraph of section 1.2 could use clarification. I suspect the word "even" in the 4th sentence should be removed, and the judgement in "There may be legitimate use" is out of place. Consider rewriting the paragraph using simpler sentences.

Section 2.3 appears to be considerations specifically for interpreting the anomalous bit in one specific extension? If so, the introduction to the section should call that out. If not, the section's structure needs improvement. The section also calls out two questions, but only discusses one of them explicitly.

[Ballot comment]
As mentioned by Sue in her OPS-DIR review:
Status: Review with nits (very minor nits) 

General comments:  Document is precise, well-written, and understandable to those who have read the documents this draft depends on.  There is not a specific operations section, but this mechanisms would be included in a PCE or other calculation engine.  This reviewer does not see any reason why additional text needs to be utilized.  Individuals who write such algorithms and programs are utilizing these mechanisms to provide better paths.

Nit #1:  section 1.2

EF and AF abbreviations are not spelled out.  Unless these are part of the RFC editor’s abbreviations, it should be spelled out.

Nit #2: section 2.3.1

/Link Los sub-TLV/Link Loss sub-TLV/

/Sub-TLV[I-D-ietf.isis-te-metric-extensions]/sub-TLV [I-D-ietf.isis-te-metric-extensions]


I would add: spell out the ERO abbreviation.

[Ballot comment]

- The shepherd write up says no IPR declarations, but the tracker
disagrees. Did the WG consider the (in this case fairly innocuous)
IPR declaration? [1]

  [1] https://datatracker.ietf.org/ipr/2200/

- Are there unexpanded acronyms here? Be worth a pass to check.

- section 1: "plagued prior attempts" screams out that it needs a
reference or two.

- section 4: I'm surprised there is no mention of the possible
impact of (D)DoS on this. Couldn't that affect path selection based
on metrics? If so, shouldn't you say how?

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

IANA has reviewed draft-ietf-teas-te-express-path-03, which is currently in Last Call, and has the following comments:

We understand that this document doesn't require any IANA 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, IANA does not 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:  (Performance-based Path Selection for Explicitly Routed LSPs using TE Metric Extensions) to Informational RFC


The IESG has received a request from the Traffic Engineering Architecture
and Signaling WG (teas) to consider the following document:
- 'Performance-based Path Selection for Explicitly Routed LSPs using TE
  Metric Extensions'
  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 2015-09-30. 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


  In certain networks, it is critical to consider network performance
  criteria when selecting the path for an explicitly routed RSVP-TE
  LSP.  Such performance criteria can include latency, jitter, and loss
  or other indications such as the conformance to link performance
  objectives and non-RSVP TE traffic load.  This specification uses
  network performance data, such as is advertised via the OSPF and ISIS
  TE metric extensions (defined outside the scope of this document) to
  perform such path selections.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-teas-te-express-path/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-teas-te-express-path/ballot/


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

  https://datatracker.ietf.org/ipr/2200/

> 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)?

Informational

> Why is this the proper type of RFC? 

Document describes how an implementation my use TE information and does
not define any protocol related formats and behaviors.

> 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
>
>  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 how to use network performance data, such as
is advertised via the OSPF and ISIS TE metric extensions (defined in
other RFCs) to perform path selection based on network performance
criteria.

> 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?

This document moved from to the TEAS WGs as part of the routing WG
changes.  This document has been fairly noncontroversial.

>
> 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?

The extensions defined in this document are compatible with earlier
implementations.  While there have been no public statements on
implementation, the authors are from multiple vendors, and
implementation is expected - or may even already exist.

> 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 Document Shepherd has reviewed the document as part of an extended
WG last calls.  The Shepherd believes this 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.

> (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?

No.

> If so, describe the review that took place.

N/A.

>
> (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 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.

Yes, see thread at
http://www.ietf.org/mail-archive/web/teas/current/msg00424.html

>
> (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 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? 

Solid among those who are interested. "strong concurrence of a few
individuals, with others being silent" is a reasonable
characterization.

> (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 discontent seen.

>
> (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.

The document passes ID nits.

>
> (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).

The IANA section was fully reviewed by the document shepherd and is
appropriate for an Informational draft.


> (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, etc.

N/A

Response 1 of 6: Alia Atlas: http://www.ietf.org/mail-archive/web/teas/current/msg00430.html
Response 2 of 6: Stefano Previdi: http://www.ietf.org/mail-archive/web/teas/current/msg00434.html
Response 3 of 6: Clarence Filsfils : http://www.ietf.org/mail-archive/web/teas/current/msg00435.html
Response 4 of 6: John Drake : http://www.ietf.org/mail-archive/web/teas/current/msg00436.html