Re: [Pce] WG Last Call for draft-ietf-pce-binding-label-sid-07 (and Code Point Allocation)

"Chengli (Cheng Li)" <> Fri, 26 March 2021 02:49 UTC

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From: "Chengli (Cheng Li)" <>
To: "Stone, Andrew (Nokia - CA/Ottawa)" <>, "" <>, "" <>
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Thread-Topic: [Pce] WG Last Call for draft-ietf-pce-binding-label-sid-07 (and Code Point Allocation)
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Subject: Re: [Pce] WG Last Call for draft-ietf-pce-binding-label-sid-07 (and Code Point Allocation)
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Hi Andrew, 

Thanks for your comments, please see my reply inline.

Also, the diff is attached.


-----Original Message-----
From: Stone, Andrew (Nokia - CA/Ottawa) [] 
Sent: Saturday, March 20, 2021 4:21 AM
Subject: Re: [Pce] WG Last Call for draft-ietf-pce-binding-label-sid-07 (and Code Point Allocation)

Hi all,

Overall Support WGLC. It's an important document in the world of SRTE, and the document goes to good lengths to describe the various scenarios and combinations. 

Only one question I have for the authors and WG, for any further clarification on the following text (section 4):

  The absence of TE-PATH-BINDING TLV in PCUpd message
   means that the PCE does not specify a binding value in which case the
   binding value allocation is governed by the PCC's local policy.

I find the "governed by PCC local policy" a bit too vague and could lead to implementation interop differences. Assuming a PCInitiated LSP that been established with a BSID: If the PCE wants to withdraw the binding SID , I interpret the document as the PCE would send a PCUpdate without the TLV, but the behaviour is now up to PCC as per that text. if the PCC local policy/implementation is to do nothing, how can the PCE explicitly force-remove the BSID with a PCUpdate? In a similar manner, If the PCE does not want to change the value but PCC local policy is to treat missing TLV as remove, then PCE should always send the TLV in every PCUpdate (which I'm okay with) which is not stated, otherwise the local policy/implementation may interpret it as a removal compared to an implementation which may interpret it as being okay to not send the TLV on every PCUpdate since there was "no change". 

In summary: might need a bit of a wording to further detail "PCE wishes to withdraw" case. 

[Cheng] You are correct, there was some issues with multiple TE-PATH-BINDING TLV. This has been updated. See the diff.

The above text has been updated to - 

   The absence of TE-PATH-BINDING TLV in PCUpd message means that the
   PCE does not specify a binding value in which case any previous
   allocated binding values are withdraw.

Further, the PCC's local policy aspect has been seperated out as - 

   In the absence of any instruction from the PCE, the PCC's local
   policy dictates how the binding allocations are made for a given LSP.



On 2021-03-18, 7:09 AM, "Pce on behalf of" < on behalf of> wrote:

    Hi all,

    This message initiates a 2-week PCE WG Last Call for
    draft-ietf-pce-binding-label-sid-07. Please review and share your
    feedback, whatever it is, using the PCE mailing list. This WGLC will end
    on Thursday April 1st (no kidding).

    Moreover, we have received a request from the authors for a code point
    allocation to support interoperability testing.

    RFC 7120 requires to meet the following criteria to proceed:

    b. The format, semantics, processing, and other rules related to
    handling the protocol entities defined by the code points
    (henceforth called "specifications") must be adequately described
    in an Internet-Draft.
    c. The specifications of these code points must be stable; i.e., if
    there is a change, implementations based on the earlier and later
    specifications must be seamlessly interoperable.

    If anyone believes that the draft does not meet these criteria, or
    believes that early allocation is not appropriate for any other
    reason, please send an email to the PCE mailing list explaining why. If
    the chairs hear no objections by Thursday, March 25th, we will kick off
    the "early" allocation request.


    Dhruv & Julien


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