The MPLS WG Archive

[Robert Raszuk <rraszuk@cisco.com>]

Yet another reason for using extensions to IGPs for TE flooding (at
least in some implementations) is verification against the up to date TE
database build based on those updates and kept on the router even in the
case when you load the explicit lists from the off-line tool. 

It would be quite wastefull to attempt to signall multiple LSPs and fail
only because the off line tool did not have the most recent TE topology.

Robert.

> 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.
> > > >

-- 

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     |          |         Robert Raszuk, CCIE #3690  ICQ #12710752
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