IP voice calls are dropping the first few seconds

[cgregg]

Does anyone have an Idea of where to start troubleshooting why the first few seconds of a voice call from an IP phone is dropping the first few seconds. The set up consists of CCM 3.x a gateway and multiple IP Phones.

I will have more information tomorrow if required.

Thanks in advance,

[paul.alvarez]

what do you mean by dropping? Choppy? Call is completely disconnected? Can't hear first few seconds of conversation?...

[rwawrig]

start the troubleshooting looking if VAD (voice activity detection) is enabled.

[jbouwkamp]

Is this a connection to analog phone lines through a gateway? If so we had this exact problem and it ended up being a problem with the phone lines, the DB level was to low for the FXO card to keep a call connected, telco had to turn up the gain on the circuits.

[cgregg]

What I found out is that VAD was turned off on the Dial peer ports, so the users thought that they were dropping their connection.

I also upgraded the IOS as I was noticing parts of a voice call to the outside world and NOT internal, would like drop. I noticed alot of issues with their current IOS so after the IOS upgrade and extensive testing the problems were gone.

Thanks alot for all your help.

CURT

[kvaradar]

Hi,

If the calls are dropping after getting connected, I first suspect Codec mismatch. What codec is configured on the gateway?

[dacole]

Try CSCeb19725.

We had IP Phone to IP Phone or IP Phone to IOS Gateway (MGCP) issue.

Called IP Phone could hear caller but caller could not hear called phone for about 10 seconds. This was intermittent

Not sure if this is just a phone load or phone load and CM upgrade. We've tried the phone load only but I don't know if the problem has re-occurred as yet.

Dave