Re: Last Call on RSVP Label Allocation for Backup Tunnels

[Giles Heron <giles@goneto.net>]

Robert Raszuk wrote:
> 
> Giles,
> 
> > > For the user-plane, the failure modes which must be considered/defined are:
> > > -       simple below MPLS fabric server layer connectivity breaks;
> > > -       simple within MPLS fabric connectivity breaks (at or below the LSP
> > > level considered);
> >
> > Both of these will be detected by the RSVP signalling, won't they?
> 
> Sure but the question is when ?
> 
> Do you think that RSVP Error/Tear msgs will travel immediately - case of
> link failure or are you proposing to run RSVP refresh in the interval
> less then 1 sec - to detect the case of node failure ? The point is that
> this draft is not about detection, but about backup LSP setup and label
> allocation under the __local__ protection scheme. So let's talk on the
> subject here.

Sorry if I drifted off (or was led off) topic there.

In any case yes I would expect link failures to be detected
immediately.  Node failures presumably require some form of polling to
detect - so the questions are:

at what level should this occur (link layer, RSVP, "MPLS OAM"?)
how low is it reasonable to set the timers?
 
> If one questions the use of local protection all together please specify
> how else you will achive the same results of even less then 1 sec end to
> end traffic disruption with end to end protection under both link & node
> failures for the TE- LSP ?

I'm all for local protection - precisely because it would be so hard to
get end to end protection to meet the <1 sec goal.

Giles

> 
> Bora,
> 
> Which CCAMP IDs address the setup & label allocation of backup tunnels
> for local protection ?
> 
> R.

-- 
============================================================
Giles Heron      Principal Network Architect      Gone2 Inc.
ph: +44 7880 506185         "if you build it they will yawn"
============================================================