Re: [mpls] Martin Vigoureux's No Objection on draft-ietf-mpls-sfc-encapsulation-03: (with COMMENT)

"Andrew G. Malis" <> Fri, 15 March 2019 15:21 UTC

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From: "Andrew G. Malis" <>
Date: Fri, 15 Mar 2019 11:21:09 -0400
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To: Martin Vigoureux <>
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Subject: Re: [mpls] Martin Vigoureux's No Objection on draft-ietf-mpls-sfc-encapsulation-03: (with COMMENT)
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Thanks for your comments.

On Thu, Mar 14, 2019 at 6:24 AM Martin Vigoureux via Datatracker <> wrote:

> ----------------------------------------------------------------------
> ----------------------------------------------------------------------
> Without having looked before I was thinking this was Standard Track, I'm
> surprised it is not.

Mirja had a similar comment. When we started work on the draft, it didn't
have any normative language. However, that was added as a result of
reviews, so we'll discuss this with Deborah and the WG chairs.

> You say:
>    1.  Push zero or more labels that are interpreted by the destination
>        MPLS node on to the packet,
> and then say:
>    The receiving MPLS node then pops the SFF Label (and any labels
>    beneath it)
> So it looks like that any label which might have been pushed before the SFF
> label is/are simply ignored at the other end. I'm not asking for the
> behaviour
> to be specified and I understand that strictly speaking the text is not
> forbidding something to happen based on these labels but still it might be
> useful to explicitly say that these labels may be processed.
That's already covered in the text:

   3.  Push zero or more additional labels such that (a) the resulting
       label stack will cause the packet to be transported to the
       destination MPLS node, and (b) when the packet arrives at the
       destination node, either:

       *  the SFF Label will be at the top of the label stack (this is
          typically the case when penultimate hop popping is used at the
          penultimate node, or the source and destination nodes are
          direct neighbors), or

       *  as a part of normal MPLS processing, the SFF Label becomes the
          top label in the stack before the packet is forwarded to
          another node and before the packet is dispatched to a higher

Unless I misunderstood your point. Please let me know if I did.

Thanks again,