The MPLS WG Archive

[David Charlap <david.charlap@marconi.com>]

"Lipovetsky, Sergey" wrote:
> 
> I will try to restate the things. Please correct me if something is
> wrong.
> 
> Suppose we have two ingress routers (IP addresses: ingr1, ingr2) and
> two egress routers (IP addresses: egr1, egr2) and several TE tunnels
> defined by the following session objects:
> 
>    extended tunnel ID     tunnel ID   IPv4 tunnel end point address
> 1) ingr1                       1                       egr1
> 2) ingr1                       1                       egr2
> 
> 3) ingr2                       1                       egr1
> 4) ingr2                       1                       egr2
> 
> 5) 0                           1                       egr1
> 6) 0                           1                       egr2
> 
> All these TE tunnels can co-exist without any collisions.

Correct.

> In cases 1-4 tunnel ID is allocated for a given pair of
> ingress-egress nodes.
> In cases 5-6 tunnel ID is allocated for a given egress node.

This subdivision is splitting hairs unnecessarily.  In all cases, tunnel
ID is chosen by the ingress node, using whatever means it is configured
for (auto-generated, manually configured, off-line database, etc.)

In all cases, the session is identified by the 3-tuple of address,
tunnel ID and extended tunnel ID.  To try and define the properties of
one based on the values of the other may be an interesting intellectual
exercise, but it has no practical effect on the protocol.

-- David