Subject: [L1vpn] question on optimality

From: dimitri papadimitriou <[email-masked]>
Date: Fri, 11 Nov 2005 19:50:35 +0100

all -

during the meeting i raised the question concerning the issue about 
optimality in the context of the enhanced mode discussion - see slide 3 
of the discussion material ("More advanced Traffic Engineering: 
Optimality") - would be interesting to have further details captured 
around this requirement

thanks,
- dimitri.

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From: Tomonori TAKEDA <[email-masked]>
Date: Mon, 14 Nov 2005 00:23:21 +0900

Hi Dimitri,

Thanks for raising this issue again, which we missed to discuss in the
meeting.

In my understanding, in UNI applications, a customer chooses ingress
and egress ports, and the provider decides path within the provider
network. This applied to the L1VPN basic mode as well.

If a customer is allowed some visibility of the provider network, the
customer may be able to choose "better" ingress and egress ports. For
example, suppose ingress and egress CEs are connected to multiple PEs.
In UNI applications, a customer may choose ingress and egress ports
randomly, and CE-CE LSP may not be established due to lack of resources.
On the other hand, by having some visibility, a cusomter may choose
correct ingress and egress ports, and CE-CE LSP may be established.

Furthermore, if a part of provider network resource is dedicated to a
specific customer, and the customer is allowed to use this resource "as
you like", the customer may be able to optmize resource usage within its
limit. (This is more like "per-VPN Peer model", I think.)

Of course, we need to be careful about customer-provider trust model,
and not to over-engineer things. We may need a good balance, and that is
why it would be nice to hear WG opinions.

Comments?

Thanks,
Tomonori

On Fri, 11 Nov 2005 19:50:35 +0100