EF class bandwidth for VoIP not fully utilised

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Aug 10th, 2009
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We have a customer who has subscribed to 1M of EF ( Expedite forwarding) class bandwidth ( in a 2M link)for transporting voice, AF1 class 392K for Voice signalling. The codec used is G.729b.The problem faced by the customer is they are not able to fully utilise the 1M bandwidth allocated for voice. The number of voice calls doesn't exceed 30 although there is enough bandwidth for about 35+ calls.There are also no drops seen in EF class.

Any idea whats causing this? Any specific debug which can be captured on the router when call volume peaks?

Many Thanks


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Nicholas Matthews Mon, 08/10/2009 - 04:19
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'show isdn call-rate' on some platforms will show you if the call flow is going through a PRI.

Otherwise there isn't much in the CLI that will tell you this, and you would need VOIP monitoring software.

'show voice call stat', 'show voice call summary', and 'show call active voice brief' will allow you to see many active calls are up at any given time, but no historical data.

You may want to try switching from G.729b to G.729. G.729b is going to have a varying bandwidth since it only sends packets when there is speech. If you use G.729 you will have a constant-rate codec rather than variable and you will receive better voice quality and more reliable QoS/bandwidth requirements.



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