On Thu, May 23, 2002 at 11:28:07AM -0400, Ravichander Vaidyanathan wrote:
>
> Sean,
>
> >
> > I didn't realize VRFs were part of this scenario... are you
> > putting L3 VPNs into TE LSPs? My question is, why would you
> > want to apply PBR to VPNs? Do you want to shunt certain
> > classes of traffic into LSPs that get different CoS treatment
> > by LSRs? You might be able to just mark EXP bits using
> > MQC- provided the hardware can do it- and let it go across
> > an LSP to the other PE via normal routing.
> >
>
> The guaranteed bw feature of TE LSPs could be useful for supporting
> customers who are willing pay for it. Shunting VPNs into TE LSPs with
> guaranteed bw helps ensure that this bw constraint can be met for the VPN
> customer.
True, but you need to be careful here. Just putting traffic into TE
LSPs isn't enough; if you also have non-TE traffic on the network,
there's no special queueing done to ensure that TE LSPs get any sort
of bandwidth assurance. You need to do this with IP Prec/EXP bits.
>
> The other philosophy that you brought up is to use COS with the EXP
> bits. Is there IOS support for classifying traffic into different queues
> (say WFQ) based on the MPLS EXP bits?
I don't view this as another choice vs. TE, but a complementary
approach. Use TE to spread out all your traffic, and diffserv to
handle temporary bursts/congestion at every hop.
Like Sean said, yes, generally you can do MPLS EXP queueing. Some
configurations let you specify the EXP seperately, some only allow you
to configure queueing for IP Prec, but MPLS EXP is generally treated
the same way as IP Prec.
eric
>
> thanks,
> Ravi
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