Hi,
I saw your discussion below and I came to think of
a couple of questions I have regarding MPLS-TE. Maybe you
can help me with an answer.
1) Can you set up RSVP-TE tunnels based on delay-requirements?
I only see discussions and configurations regarding
reserving a particular bandwidth.
Then of course how would you treat voip if the tunnel can not
guarantee maximum delay.
I have seen talks about using strict-priority for voip (LLQ, priority-queueing)
Would the solution then be mapping voip to a RSVP-TE (guaranteeing bandwidth)
and setting EXP to high value and use LLQ/priority-q-ing.
Will this really give me what the customer wants in a
heavily loaded network?
2) EF-Expedited Forwarding what does it give us?
As I understand it EF means setting the DSCP to a
specific value instructing equipment to
deal with the traffic as fast they can.
But can you compare Expedited Forwarding in one
vendors equipment with another vendors equipment?
Is EF really saying anything?
Will DSCP=EF be prioritized a head of DSCP=AF (Assured Forwarding of any sort)?
Regards,
Erik Johansson
Email: erik.e.johansson@skanova.com
-----Ursprungligt meddelande-----
Från: eosborne@cisco.com [mailto:eosborne@cisco.com]
Skickat: den 23 maj 2002 19:04
Till: vravi@research.telcordia.com
Kopia: crockers@mail.trinicom.com; cisco-nsp@puck.nether.net
Ämne: Re: [nsp] Mapping traffic into MPLS tunnels
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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