IP phone alarm entries

[jsaad]

I have a BCM 400 4.0 with 9 remote telephones. I'm consistently seeing logs or alarms that show, interarrival jitter buffer exceeded acceptable limits and some users complain of poor quality phone calls.

We're using cisco pix 506e routers with a VPN. All locations are cable modem and the BCM is on a T1. Of course the cisco units don't do QoS and there is no QoS capable switch present anywhere. We're using G.729 for the call codec.

I suppose I've answered my own questions, but I'm just looking for any advice on fine tuning the BCM side to make some improvements.

 

[cook1082]

Try Jitter small.

 

[gwebster]

You are at least partially in a no-win situation. G729 codecs use less bandwidth than G711 but will always result in a perception of lower voice quality under the same network (latency, packet loss, jitter) conditions. Jitter beyond the acceptable range essentially translates to the same result as packet loss.

If your configuration is a single IP Phone (or even a couple) on each cable modem then there should be enough bandwidth for G711. If your T1 can support it, then may be counterintutive but try switching to G711 rather than G729.

 

[jsaad]

ok, thanks. I will try jitter small and see, then maybe switch to g711