RE: SG view of the ASP

Chris,

> -----Original Message-----
> From: [email protected] [mailto:[email protected]]On
> Behalf Of Chris Benson
> Sent: Friday, February 10, 2006 1:22 PM
> To: [email protected]
> Subject: RE: [Sigtran] SG view of the ASP
>
>
> On Fri, 10 Feb 2006, Tolga Asveren wrote:
>
> > Ilie,
> >
> > > -----Original Message-----
> > > From: Ilie Glib [mailto:[email protected]]
> > > Sent: Friday, February 10, 2006 12:39 PM
> > > To: Tolga Asveren
> > > Cc: [email protected]
> > > Subject: Re: [Sigtran] SG view of the ASP
> > >
> > >
> > > Hello Tolga,
> > >
> > > First sentence
> > >
> > > >       The optional ASP Identifier parameter contains a
> unique value that
> > > >       is locally significant among the ASPs that support an AS.
> > >
> > > looks confusing because of "AS" at the end. ASP_UP can be sent before
> > > any knowledge about ASes is available in SG. Therefore ASP ID shall
> > > have SG or SGP uniqueness scope. I would prefer SGP scope, to fit the
> > > IPSP-IPSP traffic case best.
> > [TOLGA]I think the idea was to coordinate the ASP-Id among ASPs
> serving a
> > specific AS in a way -which is impelementation dependent-,
> where each ASP is
> > assigned a unique ASP-Id. Once this is done on ASP side, I don't see why
> > knowledge about SG side is necessary but I may be missing something.
>
> But ... if an ASP-UP is sent before any knowledge about ASes
> is available in the SG, then how can the SG (in the discuused
> secnario represented by two SGPs) differentiate between:
> (a)  only one remote ASP (sending ASP-UP to both SGPs), and
> (b) another AS-side configuration of two independent ASPs
> which happen to have the same numeric ASP ID but [are going to]
> belong to different ASes?
[TOLGA]Let's consider the following case: single SGP, two ASPs, each of them
are serving different AS and happen to be assigned the saem ASP-Id.

      AS1            AS2
      Id=1           Id=1
   +------+      +-------+
   | ASP1 |      |  ASP2 |
   +---+--+      +---+---+
       |             |
 ***************************
 * +---+-------------+---+ *
 * |        SGP1         | * SG1
 * +---------------------+ *
 ***************************

Both ASPs send ASPUP with AspId=1. SGP1 is unable to identify the ASPs yet.
If identifying ASPs in that stage is necessary, I agree that ASP-Id should
be unique among all ASPs interacting with the SG, not only among the ones
serving the same AS -unless I am missing something again-.