On Thu, Jun 21, 2001 at 07:46:47AM -0700, Krishna Doddapaneni wrote:
> Hi Eric,
> Thanks for your reply.
> If i configure path protection the way suggested by you.How would the
> ingress router or the head node be notified when a failure occurs in the
> path? Does it use PathERR message or uses special notifiaction message
> as specified by draft-chang-mpls-path-protection(A path/Restoration
> Mechanism for MPLS Networks)?
There's no special mechanisms just because you changed the autoroute
metric. The headend finds out via a PathERR (or IGP flood change, the
two race) that its path is no longer valid. What pre-establishing the
backup tunnel does for you is to save the time it would take to
re-calculate a new path if necessary (milliseconds, trivial) and
re-signal that path (RSVP, milliseconds to seconds, can be longer than
you'd like).
eric
> Thanks a lot,
> Krishna
>
> Eric Osborne wrote:
> >
> > On Tue, Jun 19, 2001 at 03:43:36PM -0400, Krishna Doddapaneni wrote:
> > > Hi Guys,
> > > Does cisco supports path protection in MPLS ?In the cisco website i saw
> > > the support for only link protection.Is Cisco thinking of supporting
> > > node protection in the near future?
> >
> > Are you asking about node protection, or path protection?
> >
> > Both are at varying stages of work - have your favorite cisco sales
> > folks get in touch with me if you want more info.
> >
> > You can do a limited path-protection-like thing now by
> >
> > - configuring 2 tunnels to the same destination
> > - making sure they don't take the same physical path (this can be
> > tricky to do large-scale or with any dynamicity (is that a word?))
> > - configure the "primary path" with
> > tunnel mpls traffic-eng autoroute metric relative -2
> > - and the backup path with
> > tunnel mpls traffic-eng autoroute metric relative -1
> >
> > <obCisco>
> > path protection is nifty, but IMHO doesn't scale that well. Link and
> > node protection are far more scalable. There are a few cases where
> > path protection is useful, but not as many as people seem to think...:)
> > </obCisco>
> >
> > eric
> >
> > > Thanks in advance,
> > > Krishna
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