[c-nsp] VOIP Quality with Multilink PPP

Mark Kent mark at noc.mainstreet.net
Wed Sep 6 11:37:34 EDT 2006


>> I am about to deploy a large MPLS network and have a number of CE
>> locations receiving nxT1 with MLPP.  I am running the standard priority
>> queuing for voice and CBWFQ underneath that.

I recently turned off the fancy stuff at a site with 2xT1 on 
a 2621.   Things worked OK for two or three simultaneous calls,
but when there were five or six (g711) calls the users started to
notice serious voice quality problems.

The cpu on the router was up at 50%, while it was doing nothing
but handling the voice traffic.

So, I dropped the MLPPP, use one T1 for data, one T1 for voice,
no priority queuing, just an "ip policy route-map" to send the
voice out the right T1 and that's it.

They don't get faster than 1.5Mbs downloads anymore, but the CPU load
doesn't get over 8% and the EndUsers are happy, no voice quality
complaints since the change.

BTW, this was for a case with two very local T1, over the same carrier.

Just FYI,
-mark


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