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

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

>Thank you for your reply. I understand what you
>are saying and agree that this could be useful.
>
>However, if 2 tunnels have the same <ingress, egress>
>but different instance ids, 2 questions come to
>mind -
>a) MUST they have the same TunnelIndex?

         No, definitely not. You can have as many
tunnels from point A to point B as your network
will support.

>b) Besides Ifindexes, does this save anything else
>    at the egress or the ingress over 2 regular
>    tunnels between the same <ingress, egress>
>    assuming one regular LSP is backing up another
>    and is pre-signalled. Seems to me that this is
>    equivalent to having tunnels with multiple
>    instances.

         Honestly, you can do it either way and
the MIB will support it; it is really up to your
implementation to decide. We did this on purpose
when we designed the MIB so that we could support
all of the cases I described earlier.

         --Tom




>Did I get it wrong?
>
>TIA,
>-aos
>
>--- "Thomas D. Nadeau" <tnadeau@cisco.com> wrote:
> >
> > >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
> >
> >
> >
>
>
>
>__________________________________________________
>Do You Yahoo!?
>Spot the hottest trends in music, movies, and more.
>http://buzz.yahoo.com/