From: "Les Ginsberg (ginsberg)" <ginsberg@cisco.com>
To: "Alvaro Retana (aretana)" <aretana@cisco.com>, "Benoit Claise (bclaise)"
 <bclaise@cisco.com>, The IESG <iesg@ietf.org>
Thread-Topic: [Isis-wg] Benoit Claise's No Objection on
 draft-ietf-isis-sbfd-discriminator-02: (with COMMENT)
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Date: Wed, 18 Nov 2015 19:27:15 +0000
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Cc: "draft-ietf-isis-sbfd-discriminator@ietf.org"
 <draft-ietf-isis-sbfd-discriminator@ietf.org>,
 "isis-wg@ietf.org" <isis-wg@ietf.org>, "chopps@chopps.org" <chopps@chopps.org>,
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Subject: Re: [Isis-wg] Benoit Claise's No Objection on
 draft-ietf-isis-sbfd-discriminator-02: (with COMMENT)
Precedence: list

Alvaro -

I think you are referring to this text from https://www.ietf.org/id/draft-i=
etf-bfd-seamless-base-05.txt

Section 3

"...Allocated S-BFD discriminators may be advertised by
   applications (e.g., OSPF/IS-IS)."

This is (in my view) poorly worded bordering on inaccurate.

In the context of the IS-IS/OSPF drafts we are defining a way to advertise =
the S-BFD Discriminator(s) assigned to a given node. This does not imply an=
y usage of these values by the IGPs.=20

It is conceivable that the IGPs could find a use for an S-BFD session and i=
n that context the IGPs would be an S-BFD client and considered an "S-BFD a=
pplication". But that is NOT what is covered in the current IGP drafts - no=
r is it within scope.
So I reiterate, the current discussion regarding how applications decide wh=
ich S-BFD discriminator should be used is out of scope for the existing IGP=
 drafts.

The entire discussion belongs in the BFD WG.=20

   Les


> -----Original Message-----
> From: Alvaro Retana (aretana)
> Sent: Wednesday, November 18, 2015 10:12 AM
> To: Les Ginsberg (ginsberg); Benoit Claise (bclaise); The IESG
> Cc: draft-ietf-isis-sbfd-discriminator@ietf.org; chopps@chopps.org;
> menachemdodge1@gmail.com; isis-chairs@ietf.org; isis-wg@ietf.org
> Subject: Re: [Isis-wg] Benoit Claise's No Objection on draft-ietf-isis-sb=
fd-
> discriminator-02: (with COMMENT)
>=20
> On 11/18/15, 12:47 PM, "Les Ginsberg (ginsberg)" <ginsberg@cisco.com>
> wrote:
>=20
> Les:
>=20
> >Neither IS-IS nor OSPF are the "application" here. We are simply the
> >transport for an opaque piece of information. It makes no sense to me
> >to ask the IGPs to clarify what is an issue between S-BFD and an applica=
tion.
>=20
> What you say makes sense.
>=20
> It also makes sense to me that one could argue that since we're transport=
ing
> opaque information we could also include an extra piece of opaque
> information to let someone else know what the first piece was for.
> Note that I'm offering that scenario just as an example of the fact that =
there
> are at least a couple of potential interpretations.
>=20
> Because of the language used in the Base S-BFD draft (where it does call
> OSPF/IS-IS an "application", [1]), I just want to play it safe and make s=
ure
> we're not pointing at each other and that result won't be that no one doe=
s
> the mapping.
>=20
> Thanks!
>=20
> Alvaro.
>=20
>=20
> [1]
>=20
>    session.  Allocated S-BFD discriminators may be advertised by
>    applications (e.g., OSPF/IS-IS).  Required result is that
>    applications, on other network nodes, possess the knowledge of the
>    mapping from remote entities to S-BFD discriminators.  The reflector
>=20