RE: [nsp] VOIP Over ATM 7200VXR's ?

From: Kevin Gannon (kgannon@lancomms.ie)
Date: Tue Oct 16 2001 - 04:12:35 EDT


> We are looking at running VOIP over some ATM PVCs the problem I think
> we are going to run into is queueing. The 7200VXRs do not seem to
> support WFQ at the PVC rates we run (90Mps).

WFQ is not supported for any link speed over 2Mbps due to CPU/memory
constraints.

Except DWFQ ;-) but only on the RSPs Grrrrr.

> Questions:
> 1. With FIFO do you get a seperate set of queues for each
sub-interfaces,
> so if we ran up a seperate PVC/Interface then we could live with FIFO
on
> just this interface.

That's the default anyways. You'd be better off with WRED than FIFO,
though.

Hmmm why didnt I think about that, maybe I have a RED alergy due to
the nasty things we have seen on our GSRs. Due you know of any sample
configs for WRED and VOIP ?

> 2. Do the newer queueing features LLQ/CBWFQ support higher data
> rates ?

LLQ over ATM subinterfaces is supported in 12.1T and later. Be sure to
use WRED in the class-default otherwise the default WFQ will kill your
CPU.

> 3. Is anyone brave enough to run VOIP with FIFO ?

Not anyone who likes clear audio.

At least our logic isnt gone nuts.

> 4. We are even willing to run with a TDM/CES solution and buy nailed
up
> bandwidth but there is only a full length CES card which means
getting
> rid of the existing ATM PA's :o(.

Yuck. CES is evil.

I agree but we were getting desperate.

Regards,
Kevin



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