The MPLS WG Archive

[Lou Berger <lberger@labn.net>]

Yakov,
         See below.

At 05:59 PM 6/27/2006, Yakov Rekhter wrote:

>Lou,
>
>[clipped...]
>
> > > > > > >    The P2MP ID provides an identifier for the set of
> > > > > > >    destinations of the P2MP TE Tunnel.
> > > > > > >
> > > > > > >The last sentence above has to be deleted.
> > > > > >
> > > > > > why, what's incorrect about it?
> > > > >
> > > > >To begin with, the last sentence states that the P2MP ID, *by itself*
> > > > >"provides an identifier for the set of destinations of a given P2MP
> > > > >TE Tunnel". However, since a given P2MP ID, *by itself*, may not
> > > > >be unique, how could it unambiguously identify the set of destinations
> > > > >of such tunnel ?
> > > >
> > > > You are 100% correct, how about fixing it by saying:
> > > > "The P2MP ID together with Tunnel ID, Extended Tunnel ID provide an
> > > > identifier for the set of destinations of the P2MP TE Tunnel."
> > >
> > >Given that P2MP ID is unique within the scope of the root, why a
> > >tuple <Extended Tunnel ID, P2MP ID> is not sufficient to identify
> > >the set of destinations of a P2MP tunnel ? After all, you agreed
> > >further down that such a tuple identifies a P2MP tunnel.
> >
> > Because this would preclude the use of tunnel ID to further partition
> > the session space (as is done today for P2P-TE.)  The tuple I
> > mentioned included all three.
>
>You, yourself agreed that "A combination of this address and P2MP
>ID provides a globally unique identifier for the P2MP tunnel."

Well actually my point was: "... the uniqueness of the tuple <P2MP 
ID, Tunnel ID, Extended Tunnel ID>. "

>Since the set of destinations of a P2MP tunnel is just a part of
>the tunnel, identifying the tunnel should be sufficient in order
>to identify the set of destinations.

right, and all three fields are needed.

>Since a tuple <Extended Tunnel ID, P2MP ID> is sufficient to identify
>the tunnel, the same tuple is sufficient to identify the set of
>destinations of the tunnel. Therefore, the Tunnel ID is not
>needed to identify the set of destinations of the tunnel.

we disagree.

>Yakov.
>
>P.S. I would also caution against trying to draw too much analogy
>with the P2P tunnels. As I explained to you in one of my previous
>e-mails, the semantics of some of the fields carried in the Session
>object in P2MP tunnels is quite different from the semantics of
>their counterparts in P2P tunnels.

Sure, but you've not stated any reason or need to change the 
semantics wrt tunnel ID...

Lou 


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