Call Delays Slowly until there is a large gap then audio degrades


I am very new to the systems and have been working day and night on NAT problems getting sips to register over the WAN… I was able to do that but now when calling from a local sip softphone client to another over the wan the call rings picks up and the party is right there… As we talk… the delay from when we speak to the time they get the audio gets larger and larger with time… after about 10 to 15 mins the call is really delayed… then after that the audio gets packet loss and you cant even understand them… Then you call again and your back to normaly audio and no delay. It didnt look like it was using much bandwidth and maybe it was… I am on Comcast and i dont know if that has something to do with it and vonage / slingboxes work great… Any ideas on what to look for to fix this problem?



ping the far end from both your PBX and the PC with softphone
make the call watch the ping times do they increase??

Do you have any QOS on the local network??
Do the users run any Bittorrent apps or do any online gaming??
Do you have any other server on the network doing anything

And yes Comcast does choke bandwidth on higher ports to cause Peer 2 Peer file sharing to slow down.