Subject: Peer model

From: "Giovanni Fiaschi" <[email-masked]>
Date: Tue, 19 Sep 2000 17:30:49 +0200

I don't follow the definition of the Peer Model in
draft-many-ip-optical-framework.
Even in the most integrated MPLS scheme, two layers still exist, a
connectionless IP layer and a connection oriented transport (otherwise the MPLS
definition is to fade away). This said, two tasks have to be accomplished:
1. compile the IP routing tables in the IP layer,
2. find routes for LSPs in the transport layer.
Two different network representations are needed by the two tasks, the transport
network will probably remain unchanged in time, while the IP will be modified by
the set-up and tear down of the LSPs.
I think that it would be more accurate to define the Peer Model as a network in
which LSP can be terminated at any node.
In the overlay model instead there is a clear distinction between:
1 - transport users, that is routers or other clients that can terminate LSPs
(sometimes called Termination Capable) and that can issue UNI requests,
2 - transport nodes, that is transport switches that do not perform traffic
routing at the IP layer (sometimes called Termination Incapable).
The transport nodes are in turn classified into:
1 - border nodes, that can accept UNI requests, and
2 - core nodes, that are only connected to transport nodes, never to users.
In both models, anyway, two routing instances are needed to operate two distinct
layer networks. Possibly (e.g., in the peer model) the two routing instances run
on the same nodes.

Can anybody comment on this?

Giovanni Fiaschi