IS-IS Path Control and Reservation
draft-ietf-isis-pcr-05

[Ballot comment]
This comment from Suresh Krishnan's Gen-ART review seems relevant:

There is no reference for the format of the Bandwidth fields in Sections 6.3
and 6.4. I am assuming this refers to the Single Precision format (binary32)
from IEEE 754. If so, please add an explicit reference to this.

[Ballot comment]
As mentioned by the Linda Dunbar in her OPS-DIR review:
Minor issues:

Why the Bandwidth Constraint sub-TLV is not same as the Bandwidth Sub-TLV defined by
https://tools.ietf.org/html/draft-ietf-isis-te-metric-extensions-07#page-10?

Need to make sure that the Bandwidth Sub-TLV (unidirectional available bandwidth, unidirectional utilized bandwidth sub-TLV, etc), of draft-ietf-isis-te-metric-extensions is consistent.

Regards, Benoit

[Ballot comment]
I was going to ask to discuss this:

  The lowercase forms with an initial capital "Must", "Must Not",
  "Shall", "Shall Not", "Should", "Should Not", "May", and "Optional"
  in this document are to be interpreted in the sense defined in
  [RFC2119], but are used where the normative behavior is defined in
  documents published by SDOs other than the IETF.

...because I think this is a too-subtle distinction that would be confusing to many readers.  But you don't appear to actually have any such terms in the document.  Please remove that paragraph.

[Ballot comment]
This is a well written document.  I have a couple of major comments that should be addressed before publication (and some minor ones/nits below).

1. In Section 6.1. (Topology sub-TLV) I think there's a small RFC2119 conflict. "The variable length Topology sub-TLV MUST be used to describe an explicit tree.  The Topology sub-TLV MAY be also used for describing a…GADAG".  That text says that the sub-TLV has to always (MUST) be used to describe an ET, and that it can also describe a GADAG.  I think that clearly it is one or the other.  Suggestion:
    NEW>
    The variable length Topology sub-TLV is used to describe an
    explicit tree.  The Topology sub-TLV may be also used for
    describing a Generalized Almost Directed Acyclic Graph (
    GADAG).

2. Section 7. (MRT-FRR Application) talks about the specific use of I-D.ietf-rtgwg-mrt-frr-algorithm.  However, the description doesn't match the Default MRT Profile as specified in draft-ietf-rtgwg-mrt-frr-architecture — please include in this document a description of the MRT Profile used.


Minor/Nits:

1. It is nice that you put references in Section 3. (Terminology and Definitions) for each entry.  However, the definitions are not exactly the same as the source — for example, the definitions in this document and in I-D.ietf-rtgwg-mrt-frr-architecture are similar, but not the same. I'm sure some of the differences are just word choices, but I find that it may be confusing.

2. In Section 2. (Conventions Used in This Document) I found the second paragraph ("The lowercase forms with an initial capital…") interesting, but then couldn't find any cases where the words were used.  Did I miss them?  If they're not used I would delete the paragraph to avoid confusion.

3. Section 4. (Explicit Trees)
* "An ET MUST NOT contain Cycles."  I'm guessing that "Cycles" refers to loops, right?  I just wanted to clarify because you used a capital C — nothing wrong with that, just that it might be a special term.  BTW, the fact that an ET is defined as loop-free should cover this anyway.
* s/Unidirectional Utilized Bandwidth/Unidirectional Bandwidth Utilization

4. Section 8. (Summary) is superfluous.

[Ballot comment]
This is a well written document.  I have a couple of major comments that should be addressed before publication (and some minor ones/nits below).

1. In Section 6.1. (Topology sub-TLV) I think there's a small RFC2119 conflict. "The variable length Topology sub-TLV MUST be used to describe an explicit tree.  The Topology sub-TLV MAY be also used for describing a…GADAG".  That text says that the sub-TLV has to always (MUST) be used to describe an ET, and that it can also describe a GADAG.  I think that clearly it is one or the other.  Suggestion:
    NEW>
    The variable length Topology sub-TLV is used to describe an
    explicit tree.  The Topology sub-TLV may be also used for describing
    a Generalized Almost Directed Acyclic Graph (GADAG)

2. Section 7. (MRT-FRR Application) talks about the specific use of I-D.ietf-rtgwg-mrt-frr-algorithm.  However, the description doesn't match the Default MRT Profile as specified in draft-ietf-rtgwg-mrt-frr-architecture — please include in this document a description of the MRT Profile used.


Minor/Nits:

1. It is nice that you put references in Section 3. (Terminology and Definitions) for each entry.  However, the definitions are not exactly the same as the source — for example, the definitions in this document and in I-D.ietf-rtgwg-mrt-frr-architecture are similar, but not the same.  I'm sure some of the differences are just word choices, but I find that it may be confusing.

2. In Section 2. (Conventions Used in This Document) I found the second paragraph ("The lowercase forms with an initial capital…") interesting, but then couldn't find any cases where the words were used.  Did I miss them?  If they're not used I would delete the paragraph to avoid confusion.

3. Section 4. (Explicit Trees)
* "An ET MUST NOT contain Cycles."  I'm guessing that "Cycles" refers to loops, right?  I just wanted to clarify because you used a capital C — nothing wrong with that, just that it might be a special term.  BTW, the fact that an ET is defined as loop-free should cover this anyway.
* s/Unidirectional Utilized Bandwidth/Unidirectional Bandwidth Utilization

4. Section 8. (Summary) is superfluous.

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

IANA has completed its review of draft-ietf-isis-pcr-03.txt. If any part of this review is inaccurate, please let us know.

IANA understands that, upon approval of this document, there is a single action which IANA must complete.

In the Sub-TLVs for TLV 144 subregistry of the IS-IS TLV Codepoints registry located at:

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

the following, existing, temporary registrations will be made permanent and their reference will be changed to [ RFC-to-be ]:

Type Description Reference
---- ---------------------------- -------------
21 Topology sub-TLV [ RFC-to-be ]
22 Hop sub-TLV [ RFC-to-be ]
23 Bandwidth Constraint sub-TLV [ RFC-to-be ]
24 Bandwidth Assignment sub-TLV [ RFC-to-be ]
25 Timestamp sub-TLV [ RFC-to-be ]

IANA 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 only to confirm what actions will be performed. 

Thank you,

Sabrina Tanamal
IANA Specialist
ICANN

The following Last Call announcement was sent out:

From: The IESG
To: "IETF-Announce"
CC: isis-chairs@ietf.org, "Hannes Gredler" , draft-ietf-isis-pcr@ietf.org, hannes@gredler.at, akatlas@gmail.com, isis-wg@ietf.org
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (IS-IS Path Computation and Reservation) to Proposed Standard


The IESG has received a request from the IS-IS for IP Internets WG (isis)
to consider the following document:
- 'IS-IS Path Computation and Reservation'
  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 2015-12-21. 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


  IEEE 802.1Qca Path Control and Reservation (PCR) specifies explicit
  path control via IS-IS in Layer 2 networks in order to move beyond
  the shortest path capabilities provided by IEEE 802.1aq Shortest Path
  Bridging (SPB).  IS-IS PCR provides capabilities for the
  establishment and control of explicit forwarding trees in a Layer 2
  network domain.  This document specifies the sub-TLVs for IS-IS PCR.




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

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


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

  https://datatracker.ietf.org/ipr/2533/

AD Review comments to be addressed:

Minor:

1)  In Section 6.2 h:  How to tell if a Delay Constraint is present isn't clearly described.  I assume that one can tell by calculating the expected length of the Hop sub-TLV without the Delay Constraint and then comparing that value to the actual length (as reported in the TLV).  If the actual length is 6 bytes more, then there is a Delay Constraint.  If that's the mechanism, could you please clearly write it down.  As described, it sounds like the way to tell is simply by trying to parse the last 6 bytes as a TLV.  I am assuming that there's a reason you didn't simply use an additional flag to indicate whether the Delay Constraint is present - because the trick above only works once per TLV.

2) In Sec 6.4 f and 6.2 c7:  For reserved bits, generally it is good to describe them as "MUST be set to 0 on sending and the value MUST be ignored on reception".  This allows extensions to work in the future.

Nits:

a) In Figure 1, the size of the Res & Base VID is described as (0 or 2 bytes).  If present, based on the description for (d) and (e), I think it is always 2 bytes.  The figure should reflect this.  The field is missing - not 0 bytes - if the "Num Base VIDs" is 0.

b) I see the same issue in Figure 3.  If you want to show the variability, perhaps indicate (n bytes if present) or such.

(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?

      A Standards Track RFC is being requested and is indicated in the
      title page header.

(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 is a liason document coming from the IEEE 802.1Qca Path Control
      and Reservation (PCR) STO group. PCR specifies explicit path control
      via IS-IS in Layer 2 networks in order to move beyond the shortest path
      capabilities provided by IEEE 802.1aq Shortest Path Bridging (SPB).
      IS-IS PCR provides capabilities for the establishment and control
      of explicit forwarding trees in a Layer 2 network domain.

Working Group Summary:

      All that IEEE PCR need is codepoints for their protocol extension.
      Since ISIS-wg is now the sole gatekepeer for IS-IS codepoints,
      we have asked the PCR group to come up with a short draft how
      these code points are used.

      There has not been much controversy around extending IS-IS
      in support of Layer-2 explicit trees.

Document Quality:

      This document has been a WG document for more than 6 months.
      It is stable, without changes to the technical solution for more
      than 6 months.

Personnel:

      Hannes Gredler is the Document Shepherd.
      Alia Atlas 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 IS-IS 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?

    Yes.

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

      Yes.

      https://datatracker.ietf.org/ipr/search/?submit=draft&id=draft-ietf-isis-pcr

      There wasn't any discussion. IPR on drafts is quite common.

(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 from the WG and others outside the WG that
      this document can progress.

(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.

      There are two minor nits on outdated references - those are expected
      to get resolved during the IESG submission.

(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?
 
      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).
 
    This document defines seven new subTLVs for the SPB TLV 144.
    which have been early allocated.
    http://www.iana.org/assignments/isis-tlv-codepoints/isis-tlv-codepoints.xhtml#tlv-144

(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.