Re: [mpls] WGLC for draft-ietf-mpls-bfd-directed

Greg Mirsky <gregimirsky@gmail.com> Thu, 25 May 2017 14:26 UTC

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From: Greg Mirsky <gregimirsky@gmail.com>
Date: Thu, 25 May 2017 22:26:38 +0800
Message-ID: <CA+RyBmXS8VeEU08mZcese1eM_xqRUQHF88EWrTddTiQhdSpROQ@mail.gmail.com>
To: "Carlos Pignataro (cpignata)" <cpignata@cisco.com>
Cc: "n.leymann@telekom.de" <N.Leymann@telekom.de>, mpls <mpls@ietf.org>, "mpls-chairs@ietf.org" <mpls-chairs@ietf.org>
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Subject: Re: [mpls] WGLC for draft-ietf-mpls-bfd-directed
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Dear Carlos,
thank you for taking two minutes to write the message. From it all I've
found only one concern that, in my view, may be considered technical. Thus
I'll bring it to the forefront and will try to explain how the situation
may be handled.
You wrote:
1. This approach assumes that FECs do not ever change. A reverse path is
instructed at setup/bootstrap with MPLS LSP Ping — what happens if paths
change?!? If a return tunnel is suddenly deleted from underneath?
I consider it to be the case that should be handled by properly operating
the network rather then auto-discovering it and auto-recovering. I hardly
believe that a tunnel may be "suddenly deleted" without the operator being
aware of that. And if that is the case, then the operator may proactively
re-signal return path for those BFD sessions that may be affected by the
planned change in the network. Even more, BFD sessions to decrease chance
of receiving false negative during period the remote BFD peer switches to
new recommended path.

Thank you for the editorial suggestion to consider renaming the section.
We'll discuss and share our proposal to improve the wording.

Others may decide to respond to the rest of your message. There's nothing
of technical substance, as I see it.

Regards,
Greg

On Wed, May 24, 2017 at 11:36 PM, Carlos Pignataro (cpignata) <
cpignata@cisco.com>; wrote:

> Nic,
>
> I do not support advancing this document in its current form. It has many
> technical deficiencies, some of which are listed and described below.
>
> I also believe your WGLC note should have been much more detailed and
> comprehensive.
>
> I believe this is the 3rd WGLC on this document, correct? (That gives a
> new meaning to “Last” :-) If so, that should have also been clarified in
> the WGLC email, with a much more clear explanation and comprehensive set of
> details of how concerns were discussed and addressed.
>
> > The authors have updated draft-ietf-mpls-bfd-directed and think that the
> draft is ready for WGLC.
>
> I am very concerned that there was no discussion on the list of any of
> those changes.  The authors believe the draft is ready — do you believe so
> as well, Nic? Was a shepherd review performed and is that available?
>
> > Please note that draft-ietf-mpls-bfd-directed did not pass the
> > previous working group last call, because of an IPR disclosure:
>
> Is that the 1st or 2nd WGLC? I think this statement is an
> oversimplification. There were many technical concerns.
>
> Anyway, scanning through this document, some technical issues:
>
> 1. This approach assumes that FECs do not ever change. A reverse path is
> instructed at setup/bootstrap with MPLS LSP Ping — what happens if paths
> change?!? If a return tunnel is suddenly deleted from underneath?
> 2. “Case of MPLS Data Plane” — is there any other non-MPLS case? This
> points to the fact of lack of review and editorial sloppiness.
> 3. “Exactly one sub-TLV MUST be included in the Reverse Path TLV.” — so
> basically, no Tunnels can be return path?!?
> 4. The “Use Case Scenario” uses 2119 language in a way that does not make
> sense.
>
> Please note, this is not an exhaustive list, but a 2 minute scan through
> the doc.
>
> Thanks!
>
> Carlos.
>
>
> > On May 24, 2017, at 2:33 AM, n.leymann@telekom.de <N.Leymann@telekom.de>;
> wrote:
> >
> > Dear Working Group,
> >
> > The authors have updated draft-ietf-mpls-bfd-directed and think that the
> draft is ready for WGLC.
> > Therefore this e-mail starts a WG LC which will end on the 7th of June.
> >
> > Please note that draft-ietf-mpls-bfd-directed did not pass the
> > previous working group last call, because of an IPR disclosure:
> >
> >   https://datatracker.ietf.org/ipr/2892/
> >
> > The authors have updated the draft and they believe that the IPR is no
> longer in scope.
> > Please notify the list if you still think the IPR is an issue and please
> state if you think it
> > is OK to continue with the publication of this document.
> >
> >   Best regards
> >
> >     Nic
> >
> >
> > _______________________________________________
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> > mpls@ietf.org
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>
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