Signaling LDP Label Advertisement Completion
draft-ietf-mpls-ldp-end-of-lib-04

[Ballot discuss]
I'm probably confused, but with respect to section 5.4 (Missing Expected End-of-LIB Notification) what are the conditions that lead a speaker to _expect_ a notification? Is it clear when this speaker starts expecting the notification and when it is reasonable to time out?

[Ballot comment]
INTRODUCTION, paragraph 4:
>                              LDP End-of-LIB

  Please expand all acronyms on first use.


Section 0, paragraph 3:
>      U and F bits: Should be set 1 and 0 respectively as per section 4
>    of LDP Capabilities [LDPCap].

  s/Should/MUST/ or else explain when it is OK to not set these bits as
  described in [LDPCap]


Section 0, paragraph 5:
>      S-bit: Must be 1 (indicates that capability is being advertised).

  s/Must/MUST/


Section 5., paragraph 1:
>    determination is a judgement call the LDP speaker makes.  The

  Nit: s/judgement/judgment/


Section 9.1., paragraph 4:
>    [TypedWC] Thomas, B., Minei, I., "LDP Typed Wildcard FEC", draft-
>              ietf-mpls-ldp-typed-wildcard-03, Work in Progress, March
>              2008.

  Expired since September 2008...

[Ballot discuss]
Section 4., paragraph 1:
>    An LDP speaker MAY signal completion of its label advertisements to a
>    peer by means of a Notification message, if its peer had advertised
>    the Unrecognized Notification capability during session
>    establishment. The LDP speaker MAY send the Notification message (per
>    FEC Type) to a peer even if the LDP speaker had zero Label bindings
>    to advertise to that peer.

DISCUSS-DISCUSS:
  Why is this only a MAY and not at least a SHOULD? In order to have any
  benefit, the speaker really needs to do this, no?

[Ballot comment]
INTRODUCTION, paragraph 4:
>                              LDP End-of-LIB

  Please expand all acronyms on first use.


Section 0, paragraph 3:
>      U and F bits: Should be set 1 and 0 respectively as per section 4
>    of LDP Capabilities [LDPCap].

  s/Should/MUST/ or else explain when it is OK to not set these bits as
  described in [LDPCap]


Section 0, paragraph 5:
>      S-bit: Must be 1 (indicates that capability is being advertised).

  s/Must/MUST/


Section 5., paragraph 1:

>    The FECs known to an LDP speaker and the labels the speaker has bound
>    to those FECs may change over the course of time.  This makes
>    determining when an LDP speaker has advertised "all" of its label
>    bindings for a given FEC type an issue.  Ultimately, this
>    determination is a judgement call the LDP speaker makes.  The

  Nit: s/judgement/judgment/


Section 9.1., paragraph 4:
>    [TypedWC] Thomas, B., Minei, I., "LDP Typed Wildcard FEC", draft-
>              ietf-mpls-ldp-typed-wildcard-03, Work in Progress, March
>              2008.

  Expired since September 2008...

[Ballot discuss]
I did not see a response to the concern raised in the Gen-ART
  Review by Brian Carpenter on 2008-March-10:

  >> 3. Unrecognized Notification Capability
  >>
  >>    An LDP speaker MAY include a Capability Parameter [LDPCap] in the
  >>    Initialization message to inform a peer that it ignores Notification
  >>    Messages that carry a Status TLV with a non-fatal Status Code unknown
  >>    to it.
  >
  > You use this to avoid the problem of a speaker not understanding
  > "End-of-LIB".  But what happens if the recipient does not understand
  > "Unrecog Notif"? Doesn't that create a similar problem during
  > initialization?

  Does the  design principle of silent discard apply here?

[Ballot comment]
This is a relatively concise and well-written specification. I beieve that the following editorial improvements would add to clarity.

1. 'End-of-LIB' is mentioned in the title, but this being the name of the message and not a very self-explaining one people may have problems in understanding what the specification is about. Replacing with something more explicit, or detailing in the abstract that 'End-ofLIB' is the name of the message would help.

2. Acronyms like FEC or TLV should be expanded at first occurance.

3. Section 5 is non-normative, including implementation and behavior guidelines. The exception is 5.4 which includes a mandatory behavior requirement without which interoperability is not possible. I would suggest moving 5.4 to section 4 - as this is note than a 'guideline' item.

[Ballot comment]
In Section 5.4;

  To deal with the possibility of missing notifications, an LDP speaker
  may time out receipt of an expected End-of-LIB Notification, and if
  the timeout occurs, it may behave as if it had received the
  notification. If the End-of-LIB Notification message is received
  after the time-out occurs, then the message should be ignored.

s/should/SHOULD ?


draft-ietf-mpls-ldp-capabilities was published as an RFC.


What is the status of ietf-mpls-ldp-typed-wildcard?

Document: LDP End-of-LIB
          draft-ietf-mpls-ldp-end-of-lib-03.txt

Intended status : Standards Track

> (1.a)  Who is the Document Shepherd for this document?  Has the
>        Document Shepherd personally reviewed this version of the
>        document and, in particular, does he or she believe this
>        version is ready for forwarding to the IESG for publication?

Loa Andersson is the document shepherd.

He has personally reviewed the I-D and believes it is ready for
forwarding to the IESG for publication.

> (1.b)  Has the document had adequate review both from key WG members
>        and from key non-WG members?  Does the Document Shepherd have
>        any concerns about the depth or breadth of the reviews that
>        have been performed?

This document has been reviewed by the MPLS working group.

> (1.c)  Does the Document Shepherd have concerns that the document
>        needs more review from a particular or broader perspective,
>        e.g., security, operational complexity, someone familiar with
>        AAA, internationalization or XML?

No concerns.

> (1.d)  Does the Document Shepherd have any specific concerns or
>        issues 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.  Has an IPR disclosure related to this document
>        been filed?  If so, please include a reference to the
>        disclosure and summarize the WG discussion and conclusion on
>        this issue.

No concerns. The document is sound.
No IPR disclosures filed.

> (1.e)  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 were no problems with consensus for this document. The document
has been carefully reviewed and all comments addressed.

> (1.f)  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
>        entered into the ID Tracker.)

No threats. No discontent.

> (1.g)  Has the Document Shepherd personally verified that the
>        document satisfies all ID nits?  (See
>        http://www.ietf.org/ID-Checklist.html and
>        http://tools.ietf.org/tools/idnits/).  Boilerplate checks are
>        not enough; this check needs to be thorough.  Has the document
>        met all formal review criteria it needs to, such as the MIB
>        Doctor, media type and URI type reviews?

All checks made. Thanks to timing, the draft would have to incorporate
the new boilerplate post 2/12/2009 prior to final publishing.

Also, the draft normatively references the 'typed wildcard' draft,
which is on standards track and soon to be requested for publishing,
and which is incorrectly declared as a possible down-ref by the nits
tool. We should ignore the nits tool in this case.

> (1.h)  Has the document split its references into normative and
>        informative?  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
>        strategy for their completion?  Are there normative references
>        that are downward references, as described in [RFC3967]?  If
>        so, list these downward references to support the Area
>        Director in the Last Call procedure for them [RFC3967].

References split.

> (1.i)  Has the Document Shepherd verified that the document IANA
>        consideration section exists and is consistent with the body
>        of the document?  If the document specifies protocol
>        extensions, are reservations requested in appropriate IANA
>        registries?  Are the IANA registries clearly identified?  If
>        the document creates a new registry, does it define the
>        proposed initial contents of the registry and an allocation
>        procedure for future registrations?  Does it suggest a
>        reasonable name for the new registry?  See [RFC2434].  If the
>        document describes an Expert Review process has Shepherd
>        conferred with the Responsible Area Director so that the IESG
>        can appoint the needed Expert during the IESG Evaluation?

An IANA section is present requesting cocepoints for:

  - a new LDP Status Code
  - a new LDP Capability

> (1.k)  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.

There are situations following LDP session establishment where it would be useful for a Label Distribution Protocol (LDP) speaker to know when its peer has advertised all of its labels.  For example, when an LDP speaker is using LDP-IGP synchronization procedures, it would be useful for the speaker to know when its peer has completed advertisement of its IP label bindings.

Similarly, after an LDP session is re-established when LDP Graceful Restart is in effect, it would be helpful for each peer to signal the other after it has advertised all its label bindings.

The LDP specification (RFC 5036) provides no mechanism for an LDP speaker to notify a peer when it has completed its initial label advertisements to that peer.

This document specifies use of a Notification message with the "End-  of-LIB" Status Code for an LDP speaker to signal completion of its    label advertisements following session establishment.

RFC 5036 implicitly assumes that new Status Codes will be defined over the course of time.  However, it does not explicitly define the behavior of an LDP speaker which does not understand the Status Code in a Notification message.  To avoid backward compatibility issues this document specifies use of the LDP capability mechanism at session establishment time for informing a peer that an LDP speaker is capable of handling a Notification message that carries an unrecognized Status Code.

>        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?

Nothing of note.

>        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?

There are no implementations that we know of. We have polled the
WG list but received no responses.

IANA Last Call comments:

Action #1:

Upon approval of this document, IANA will make the following
assignments in the "Status Code Name Space" registry at
http://www.iana.org/assignments/ldp-namespaces

Range/Value E Description Reference
------------- ----- ---------------------- ---------
0x00 0 End-of-LIB [RFC-mpls-ldp-end-of-lib-03]


Action #2:

Upon approval of this document, IANA will make the following
assignments in the "TLV Type Name Space" registry at
http://www.iana.org/assignments/ldp-namespaces

Range Description Reference
----------------- ----------------------------------- ---------
0x00 Unrecognized Notification [RFC-mpls-ldp-end-of-lib-03]


We understand the above to be the only IANA Actions for this document.

Document: LDP End-of-LIB
          draft-ietf-mpls-ldp-end-of-lib-03.txt


Intended status : Standards Track

> (1.a)  Who is the Document Shepherd for this document?  Has the
>        Document Shepherd personally reviewed this version of the
>        document and, in particular, does he or she believe this
>        version is ready for forwarding to the IESG for publication?

Loa Andersson is the document shepherd.
He has personally reviewed the I-D and believes it is ready for
forwarding to the IESG for publication.

> (1.b)  Has the document had adequate review both from key WG members
>        and from key non-WG members?  Does the Document Shepherd have
>        any concerns about the depth or breadth of the reviews that
>        have been performed?

This document has been reviewed by the MPLS working group.


> (1.c)  Does the Document Shepherd have concerns that the document
>        needs more review from a particular or broader perspective,
>        e.g., security, operational complexity, someone familiar with
>        AAA, internationalization or XML?

No concerns.

> (1.d)  Does the Document Shepherd have any specific concerns or
>        issues 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.  Has an IPR disclosure related to this document
>        been filed?  If so, please include a reference to the
>        disclosure and summarize the WG discussion and conclusion on
>        this issue.

The document is sound.
No IPR disclosures filed.

> (1.e)  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 were no problems with consensus for this document. The document
has been carefully reviewed and all comments addressed.

> (1.f)  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
>        entered into the ID Tracker.)

No threats. No discontent.

> (1.g)  Has the Document Shepherd personally verified that the
>        document satisfies all ID nits?  (See
>        http://www.ietf.org/ID-Checklist.html and
>        http://tools.ietf.org/tools/idnits/).  Boilerplate checks are
>        not enough; this check needs to be thorough.  Has the document
>        met all formal review criteria it needs to, such as the MIB
>        Doctor, media type and URI type reviews?

All checks made, there are new boiler-plate
- this references the wildcard draft, a request to publish the typed
  wildcard draft document will go out shortly, the nits-tool indicates
  as a possible down-ref, but the nits tool is wrong, the typed wildcard
  draft is on standards track.

> (1.h)  Has the document split its references into normative and
>        informative?  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
>        strategy for their completion?  Are there normative references
>        that are downward references, as described in [RFC3967]?  If
>        so, list these downward references to support the Area
>        Director in the Last Call procedure for them [RFC3967].

References split.

> (1.i)  Has the Document Shepherd verified that the document IANA
>        consideration section exists and is consistent with the body
>        of the document?  If the document specifies protocol
>        extensions, are reservations requested in appropriate IANA
>        registries?  Are the IANA registries clearly identified?  If
>        the document creates a new registry, does it define the
>        proposed initial contents of the registry and an allocation
>        procedure for future registrations?  Does it suggest a
>        reasonable name for the new registry?  See [RFC2434].  If the
>        document describes an Expert Review process has Shepherd
>        conferred with the Responsible Area Director so that the IESG
>        can appoint the needed Expert during the IESG Evaluation?

A IANA section is present requesting cocepoints for:

  - a new LDP Status Code
  - a new LDP Capability



> (1.k)  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.

  The LDP specification [RFC5036] for the Wildcard FEC element has
  several deficiencies.  This document corrects those deficiencies.  In
  addition, it specifies the Typed Wildcard FEC for the Prefix FEC
  Element Type defined in RFC5036.


  LDP [RFC5036] distributes labels for Forwarding Equivalence Classes
  (FECs).  LDP uses FEC TLVs in LDP messages to specify FECs.  An LDP
  FEC TLV includes 1 or more FEC Elements.  A FEC element includes a
  FEC type and an optional type-dependent value.

  RFC5036 specifies two FEC types (Prefix and Wildcard), and other
  documents specify additional FEC types; e.g., see RFC4447 and
  draft-ietf-mpls-ldp-p2mp-05.txt.

  As specified by RFC5036 the Wildcard FEC Element refers to all FECs
  relative to an optional constraint.  The only constraint RFC5036
  specifies is one that limits the scope of the Wildcard FEC Element to
  "all FECs bound to a given label".

  The RFC5036 specification of the Wildcard FEC Element has the
  following deficiencies which limit its utility:

      1. The Wildcard FEC Element is untyped.  There are situations
        where it would be useful to be able to refer to all FECs of a
        given type.


      2. Use of the Wildcard FEC Element is limited to Label Withdraw
        and Label Release messages only.  There are situations where it
        would be useful in Label Request messages.

  This document:

      - Addresses the above deficiencies by defining a Typed Wildcard
        FEC Element and procedures for its use.

      - Specifies use of the LDP capability mechanism [LDPCap] at
        session establishment time for informing a peer that an LDP
        speaker is capable of handling the Typed Wildcast FEC.

      - Specifies the Typed Wildcard FEC Element for the Prefix FEC
        Element specified by RFC5036.

  Note that this document does not change procedures specified for the
  LDP Wildcard FEC Element by RFC5036.


>        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?

Nothing of note.

>        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?

There are not implementations that we know of, we have polled the
wg list but no responses.