Remote-LFA Node Protection and Manageability
draft-ietf-rtgwg-rlfa-node-protection-13

[Ballot discuss]
This document mentions manageability in his title. Hence my special focus.
I'm with Eric Vyncke here. His OPS DIR review is:

Not being an expert in LFA, the review focus was only on operation.
And, due to the density and specialization of the I-D, I would like to ask the authors whether they read RFC 5706 about 'ops and mgmt guidelines', i.e., to check whether this I-D considered migration from an existing LFA to the new one, interoperations with previous LFA and how correct operations can be verified.
As the core topic is about loop-free alternates, we can assume that fault management and operations are at the core of this I-D. But, I encourage the authors to quickly review their document with RFC 5706 in mind.

After reading the document (and with basic knowledge of RLFA), I'm unable to tell at this point if RFC 7916 is still valid for this new functionality, if it needs to be updated, or even if https://tools.ietf.org/html/draft-ietf-rtgwg-rlfa-node-protection-10#section-3 is complete in light of RFC 5706. I'll be watching the discussion with interest.

[Ballot comment]
-  The resulting Remote-LFA
  alternate nexthops (also referred to as the PQ-nodes) may not provide
  node-protection for all destinations covered by the same, in case of
  failure of the primary nexthop node.

Covered by the same?

- There are also some nits and typos such as " uitilized" in the abstract.

[Ballot comment]
Overall comment: This reads rather like an informational rfc; however given that rfc7490 is standards track, I guess that's fine.

More specific comments:
- More abbreviations could be spelled out to make it easier to read.
- Not sure what section 3 tells me; but I'm also not an expert.
- Also section 3: "As already specified in Section 2.3.4 to limit the computational
  overhead of the proposed approach, forward SPF computations MUST be
  run on a selected subset from the entire set of PQ-nodes computed in
  the network, with a finite limit on the number of PQ-nodes in the
  subset."
  I guess you don't need the upper case MUST here.
- Also then in section 2.3.4: "To limit the computational overhead of the approach proposed, this
  document proposes that implementations MUST choose a subset from the
  entire set of PQ-nodes computed in the network, with a finite limit
  on the number of PQ-nodes in the subset."
  Saying "this doc recommends" and "MUST" in the same sentence seem inaccurate.
- And also section 2.3.4: Could you maybe suggest or discuss an appropriate default value?

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

The IANA Services Operator has reviewed draft-ietf-rtgwg-rlfa-node-protection-08.txt, 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
IANA Services Specialist
PTI

The following Last Call announcement was sent out:

From: The IESG
To: "IETF-Announce"
CC: rtgwg-chairs@ietf.org, akatlas@gmail.com, draft-ietf-rtgwg-rlfa-node-protection@ietf.org, "Jon Mitchell" , jrmitche@puck.nether.net, rtgwg@ietf.org
Reply-To: ietf@ietf.org
Sender:
Subject: EXTENSION OF Last Call:  (Remote-LFA Node Protection and Manageability) to Proposed Standard


The IESG has received a request from the Routing Area Working Group WG
(rtgwg) to consider the following document:
- 'Remote-LFA Node Protection and Manageability'
  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 2017-01-11. 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


  The loop-free alternates computed following the current Remote-LFA
  specification guarantees only link-protection.  The resulting Remote-
  LFA nexthops (also called PQ-nodes), may not guarantee node-
  protection for all destinations being protected by it.

  This document describes an extension to the Remote Loop-Free based IP
  fast reroute mechanisms described in [RFC7490], that describes
  procedures for determining if a given PQ-node provides node-
  protection for a specific destination or not.  The document also
  shows how the same procedure can be utilised for collection of
  complete characteristics for alternate paths.  Knowledge about the
  characteristics of all alternate path is precursory to apply operator
  defined policy for eliminating paths not fitting constraints.





The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-rtgwg-rlfa-node-protection/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-rtgwg-rlfa-node-protection/ballot/

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

  https://datatracker.ietf.org/ipr/2346/
  https://datatracker.ietf.org/ipr/2334/

The following Last Call announcement was sent out:

From: The IESG
To: "IETF-Announce"
CC: rtgwg-chairs@ietf.org, akatlas@gmail.com, draft-ietf-rtgwg-rlfa-node-protection@ietf.org, "Jon Mitchell" , jrmitche@puck.nether.net, rtgwg@ietf.org
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Remote-LFA Node Protection and Manageability) to Proposed Standard


The IESG has received a request from the Routing Area Working Group WG
(rtgwg) to consider the following document:
- 'Remote-LFA Node Protection and Manageability'
  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 2017-01-04. 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


  The loop-free alternates computed following the current Remote-LFA
  specification guarantees only link-protection.  The resulting Remote-
  LFA nexthops (also called PQ-nodes), may not guarantee node-
  protection for all destinations being protected by it.

  This document describes an extension to the Remote Loop-Free based IP
  fast reroute mechanisms described in [RFC7490], that describes
  procedures for determining if a given PQ-node provides node-
  protection for a specific destination or not.  The document also
  shows how the same procedure can be utilised for collection of
  complete characteristics for alternate paths.  Knowledge about the
  characteristics of all alternate path is precursory to apply operator
  defined policy for eliminating paths not fitting constraints.





The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-rtgwg-rlfa-node-protection/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-rtgwg-rlfa-node-protection/ballot/

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

  https://datatracker.ietf.org/ipr/2346/
  https://datatracker.ietf.org/ipr/2334/

(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.

(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

  The loop-free alternates computed following the current Remote-LFA
  specification guarantees only link-protection.  The resulting Remote-
  LFA nexthops (also called PQ-nodes), may not guarantee node-
  protection for all destinations being protected by it.

  This document describes an extension to the Remote Loop-Free based IP
  fast reroute mechanisms described in RFC7490, that describes
  procedures for determining if a given PQ-node provides node-
  protection for a specific destination or not.  The document also
  shows how the same procedure can be utilised for collection of
  complete characteristics for alternate paths.  Knowledge about the
  characteristics of all alternate path is precursory to apply operator
  defined policy for eliminating paths not fitting constraints.

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 was strong concensus for this document by the working group, the routing directorate review by Mike Shand and comments by Levente Csikor helped resolve some earlier issues with the drafts readability.

Document Quality

The document is of high quality and there is an existing implementation that has been deployed.

Personnel

Jon Mitchell, Document Shepherd
Alia Atlas, 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 was thoroughly reviewed by the document shephard and routing directorate and was found ready for publication.

(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.

Not beyond routing directorate, which was performed already.

(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.

(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 have confirmed they are only aware of the following disclosures:
https://datatracker.ietf.org/ipr/2334/
https://datatracker.ietf.org/ipr/2346/

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

Two IPR disclosures reference this document and it has been disclosed to the working group by the authors,  beyond that there has not been any active discussion on this issue.

(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? 

There is good consensus in the working group and a fair amount of feedback has been integrated into the document based on working group comments.

(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 https://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
thorough.

There is a reference [RFC7490] in the abstract that needs to be removed and replaced with straight text.

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

No additional formal reviews required based on the document content.

(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.

This document does not change the status of existing RFC's, several references are provided to the similarities and differences between it and other FRR related work.

(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 protocol changes or extensions associated with the document content, so the IANA considerations section contains no actions.

(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.

Performed normal review as well as validated with idnits.