Re: TE MIB (-06.txt) : tunnel instance

["Thomas D. Nadeau" <tnadeau@cisco.com>]

>I am a bit confused by the mplsTunnelInstance
>parameter in the MIB. Should each tunnel not have
>its own name, index etc, even if it has the same
>parameters as another tunnel. If this is so,
>mplsTunnelInstance is not needed right?
>
>Or does current equipment support such "multiple"
>instances of the tunnel? If so what advantages
>does it have over 2 tunnels which differ in the
>index and name fields.

         This is useful for several reasons. First,
it allows pre-signalled back-up tunnels to be
displayed. They will appear as different instances
of the same tunnel. You can also use alternate
instances of the tunnel to have different
constraints (paths, etc...) which can be chosen
in the event that the primary path fails and
is rerouted. Finally, you can also have parallel
tunnels. Some implementations allow multiple instances of
the same tunnel to be signaled and used in parallel,
but appear as the same tunnel interface.

         --Tom