The MPLS WG Archive

["HANSEN CHAN" <hchan@newbridge.com>]

Dan,

I agree that most MPLS implementations perform LSP path computations online. But I
always thought the working LSPs deployed in the networks are still computed
offline. You only use online computations when you're re-routing/repairing the LSPs
around some failure. Is my understanding correct?

Cheers,
Hansen

Daniel Awduche wrote:

> Hansen,
>
> Yes, many (perhaps most) contemporary implementations perform
> LSP path computations online. This is a mandatory requirement
> in some operational contexts. It's also possible to augment
> the online system with offline software tools.
>
> Cheers,
> /Dan
>
> On Thu, Apr 20, 2000 at 06:04:13PM -0400, HANSEN CHAN wrote:
> > Dan,
> >
> > To make sure I understand. Do you mean the path of LSPs is computed on the
> > node, not by software tools?
> >
> > Thanks,
> > Hansen
> >
> > Daniel Awduche wrote:
> >
> > > Actually, the original assertion/generalization is false
> > > (i.e. that "LSPs in today's MPLS network are usually computed
> > > off-node").
> > >
> > > Cheers,
> > > /Dan
> > >
> > > On Thu, Apr 20, 2000 at 02:08:22PM -0400, Anoop Ghanwani wrote:
> > > >
> > > >
> > > > > I am trying to understanding the use of TE extension of IGP in a MPLS
> > > > > network. From my understanding, you need TE extension when you're doing
> > > > > on-node path computation. However, since LSPs in today's MPLS network
> > > >                                                    ^^^^^^^^^^^^^^^^^^^^
> > > >
> > > > We're hoping it won't stay that way forever because it's limiting
> > > > to have to rely on offline tools for all traffic engineering :-)
> > > >
> > > > That means that traffic engineering would need to be more dynamic,
> > > > and the routers would play a more active role in determining paths
> > > > and possibly doing network optimization.  Hence the IGP extensions.
> > > >
> > > > > are usually computed off-node (in software tool), why would the use of
> > > > > TE extension be critical?
> > > > >
> > > > > Appreciate if someone can shed some light on this question.
> > > >