IS-IS Traffic Engineering (TE) Metric Extensions
draft-ietf-lsr-isis-rfc7810bis-05

[Ballot comment]
Rich version of this review at:
https://mozphab-ietf.devsvcdev.mozaws.net/D5671


This seems like a straightforward document.

Looking at S 14, I see the following "The following people contributed
substantially to the content of this
document and should be considered co-authors". Is this just an
artifact of the 5 author limit? Perhaps we should make an exception.







COMMENTS
S 4.1.
> 
>      A bit: The A bit represents the Anomalous (A) bit.  The A bit is set
>      when the measured value of this parameter exceeds its configured
>      maximum threshold.  The A bit is cleared when the measured value
>      falls below its configured reuse threshold.  If the A bit is clear,
>      the sub-TLV represents steady-state link performance.

Just to be clear, I have no way of knowing remotely what the threshold
is, right?


S 4.2.
>      value (in microseconds) over a configurable interval, encoded as an
>      integer value.
> 
>      Implementations MAY also permit the configuration of an offset value
>      (in microseconds) to be added to the measured delay value, to
>      facilitate the communication of operator-specific delay constraints.

I'm probably missing something, but I don't think I understand the
purpose of this. Would you mind adding a sentence or two about how you
would use this offset?


S 4.3.
> 
>      RESERVED: This field is reserved for future use.  It MUST be set to 0
>      when sent and MUST be ignored when received.
> 
>      Delay Variation: This 24-bit field carries the average link delay
>      variation over a configurable interval in microseconds, encoded as an

So the peer has no idea of what that interval is, right?

[Ballot comment]
The nice tidy diff against RFC 7810 and description in Appendix A made this
document very easy to review; thank you!

That said, I think that there are some lingering factual errors that will
require some text changes; in particular, relating to the IANA
registrations.  E.g,. Section 2 shouldn't say "this document registers new
IS-IS TE sub-TLVs" and "this document registers several sub-TLVs", since
the sub-TLVs are not new.  Similarly, one could make a case that the IANA
considerations should request for IANA to update the registrations for the
indicated sub-TLVs to point to this document instead of RFC 7810.

(I'm still balloting No Objection and not Discuss, because I trust the
responsible AD to make the right thing happen.)

[Ballot comment]
* Backward compatibility

There is text in Appendix A that provides guidance to implementers on how to handle TLVs with length 5 from RFC7810. I think this would be much more helpful inside the main body of the document. I was wondering how the backward compatibility was handled until I read through the Appendix that lists the *diffs*.

[Ballot comment]
Why does this need to least more than the usual 5 authors, especially since there is already a contributors section that says the entries should be treated as co-authors?

[Ballot comment]
I do have a question and a suggestion:

1: From the shepherd writeup:
(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.

    Pending Response at WG adoption:
    Authors: S Giacolone, D Ward
    Contributors: A Atlas, C Filsfils

    There was no IPR poll done during/after WGLC.
---
I'm not sure I really understand what happened, and if they ever replied - I'll trust that the AD did the right thing.

2: The abstract says: This document obsoletes RFC 7810.
Once this is published it won't be clear that this is a -bis. It might be useful to include something like: This document obsoletes RFC 7810 (see the Appendix for details).
(if the RFC editor will allow it that is :-))

I also agree with Mirja's comments.

[Ballot comment]
This is well written document, thank you. One small thing:

4.5.  Unidirectional Residual Bandwidth Sub-TLV


  Residual Bandwidth: This field carries the residual bandwidth on a
  link, forwarding adjacency [RFC4206], or bundled link in IEEE
  floating-point format with units of bytes per second.

Please add a Normative reference to the IEEE document.

[Ballot comment]
In section 13 it seems a little awkward to reference the "first version" and "second version" of the document since they will be published with different RFC numbers. Might be clearer to say RFC 7810 in the first instance and "this document" in the second instance.

[Ballot comment]
Based on the TSV-ART review (Thanks Yoshi!) and the information provided in the shepherd write-up, I understand that this document intends to "fix" a specific errata. However, there are  IPPM RFCs for each of these metrics that provide further insights on how the calculate them correctly, e.g. rfc3393 IP Packet Delay Variation. I will not block publication on this doc but I would still welcome and recommend if the respective references could be added to provide at least some guidance instead of just declaring calculation out of scope.

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

The IANA Functions Operator has completed its review of draft-ietf-lsr-isis-rfc7810bis-03. If any part of this review is inaccurate, please let us know.

The IANA Functions Operator has a question about one of the actions requested in the IANA Considerations section of this document.

In the Sub-TLVs for TLVs 22, 23, 25, 141, 222, and 223 (Extended IS reachability, IS Neighbor Attribute, L2 Bundle Member Attributes, inter-AS reachability information, MT-ISN, and MT IS Neighbor Attribute TLVs) registry on the IS-IS TLV Codepoints registry page located at:

https://www.iana.org/assignments/isis-tlv-codepoints/

There are existing registrations as follows:

Type Description
----------------------------------------------------
33 Unidirectional Link Delay
34 Min/Max Unidirectional Link Delay
35 Unidirectional Delay Variation
36 Unidirectional Link Loss
37 Unidirectional Residual Bandwidth
38 Unidirectional Available Bandwidth
39 Unidirectional Utilized Bandwidth

IANA Question --> Should the reference for each of these existing registrations be changed to [ RFC-to-be ]?

IANA Question --> Should any of the parameters associated with the existing registrations be changed in any way?

The IANA Functions 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 meant 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 2018-12-12):

From: The IESG
To: IETF-Announce
CC: ketant@cisco.com, Ketan Talaulikar , lsr-chairs@ietf.org, lsr@ietf.org, aretana.ietf@gmail.com, draft-ietf-lsr-isis-rfc7810bis@ietf.org
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (IS-IS Traffic Engineering (TE) Metric Extensions) to Proposed Standard


The IESG has received a request from the Link State Routing WG (lsr) to
consider the following document: - 'IS-IS Traffic Engineering (TE) Metric
Extensions'
  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 2018-12-12. 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, such as, but not limited to, financial
  information networks (e.g., stock market data providers), network-
  performance criteria (e.g., latency) are becoming as critical to
  data-path selection as other metrics.

  This document describes extensions to IS-IS Traffic Engineering
  Extensions (RFC 5305) such that network-performance information can
  be distributed and collected in a scalable fashion.  The information
  distributed using IS-IS TE Metric Extensions can then be used to make
  path-selection decisions based on network performance.

  Note that this document only covers the mechanisms with which
  network-performance information is distributed.  The mechanisms for
  measuring network performance or acting on that information, once
  distributed, are outside the scope of this document.

  This document obsoletes RFC 7810.





The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-lsr-isis-rfc7810bis/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-lsr-isis-rfc7810bis/ballot/

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

  https://datatracker.ietf.org/ipr/3257/
  https://datatracker.ietf.org/ipr/3259/

=== AD Review of draft-ietf-lsr-isis-rfc7810bis-02 ===
https://mailarchive.ietf.org/arch/msg/lsr/92-08uCr6-ctnRU9i3FHA-ucFEw

Dear authors:

Thanks for taking on this work!!

I have just a couple of comments.

(1) There are too many authors in the front page.  I know that the list was cut prior to rfc7810 being processed, and that Les was added to hold the pen on this revision, so I'll let this one proceed.  Just one thing: please group the authors by affiliation (which will reduce the size of the header).

(2) Both rfc7471 and rfc7810 can be Informative references.

(3) There's an active thread related to the definition of Available Bandwidth [1].  Please keep an eye on it and participate as needed.

I don't think the ongoing discussion is a showstopper at this point.  I am starting the IETF Last Call.

Thanks!

Alvaro.

[1] https://mailarchive.ietf.org/arch/msg/lsr/zOdpuIbCViJToCsC9mNnRmoEiQw

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?

    This RFC is Standards Track and it would obsolete an existing RFC 7810
    which is Standards Track once published.

(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 describes extensions to IS-IS Traffic Engineering
    Extensions (RFC5305) such that network performance information can be
    distributed and collected in a scalable fashion.  The information
    distributed using ISIS TE Metric Extensions can then be used to make
    path selection decisions based on network performance.

    Note that this document only covers the mechanisms with which network
    performance information is distributed.  The mechanisms for measuring
    network performance or acting on that information, once distributed,
    are outside the scope of this document.

Working Group Summary

    This bis draft update to RFC7810 was created out of an errata
    submitted that pointed out errors in the definition of certain
    bandwidth related sub-TLVs. There was a quick and unanimous
    decision to address this error by publishing this bis update.

    There have been much discusson as to how these metrics would be
    collected and how they will be used when reviewing RFC7810. A
    similar discussion also took place during the review of this
    bis draft that replaces RFC7810. On both occassions, these
    topics were deemed to be out of scope.

    During RFC7810 review, there was also concern for potential
    overhead of collecting and flooding these metrics. In response,
    the RFC7810 contains guidance as to how often the measurements
    should be collected and flooded. Additionally, the RFC7810
    recommends configuration to control measurement usage and the
    thresholds for advertisement. All of these aspects are
    unchanged in the bis draft update.

Document Quality

    The RFC7810 published over two years ago has at least two known
    implementations. There is no change to the technical solution
    in this update. The updated bis draft has identical content
    to RFC7810 except for the changes for fixing of the error
    in encoding and highlighting the changes in the appendix.

Personnel

    Ketan Talaulikar is the Document Shepherd.
    Alvaro Retana 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 each revision of the document
    and followed the discussion on the LSR mailing list.

(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.

    None

(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.

    Pending Response at WG adoption:
    Authors: S Giacolone, D Ward
    Contributors: A Atlas, C Filsfils

    There was no IPR poll done during/after WGLC.

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

    Two IPRs were disclosed against RFC 7810 as seen below
    https://datatracker.ietf.org/ipr/search/?submit=draft&id=draft-ietf-isis-te-metric-extensions

    These are also inherited by this bis update to that document.
    However, they are not currently reflecting on this document
    and this needs to be fixed/updated.

    This IPR has been shared during adoption call and discussion
    and there were no objections.

(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 consensus within the WG to progress this document.

(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.

    No nits pending

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

    Not applicable

(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?

    None that are not ready or unclear

(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.

    None

(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 will obsolete RFC 7810. This is clarified in
    the title page and also changes described in the Appendix section.

(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 allocations made via RFC 7810 are unchanged and this
    document does not bring in any new 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.

    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.

    Not Applicable