Queued callbacks causing dead air at the start of inbound calls.

[kakashi]

We have an ads queue for sales where we receive high volumes of calls in a very short period of time. Between 30 to 200 in a minute sometimes. We started noticing a number of calls around this time have dead air when an agent accepts the call. The caller can't hear the agent, and vice versa, for anywhere between 5 to 30 seconds. After multiple rounds of testing, we have narrowed it down to only occurring when QCB calls are being connected. The audio is fine for the rush of calls until that happens. Does anyone have any ideas as to what might be causing that?

Things to note. The hardware on the server doesn't break a sweat. We sit around 15 percent cpu during the rush of calls and about 5 percent ram usage. This affects inbound calls for all queues. Not just the one with QCB. We have run wireshark on the server and we were able to capture the audio from the caller when the delay occurs. Not the agent.

 

[JohnS_3CX]

Hi,

Firstly I would test callbacks to ensure they work under regular conditions, before investigating them during peak calls.

Please read this first:
https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/

 

[cobaltit]

We have an ads queue for sales where we receive high volumes of calls in a very short period of time. Between 30 to 200 in a minute sometimes. We started noticing a number of calls around this time have dead air when an agent accepts the call.

Curious on the details. So this was running for 1 day, 1 month, 1 year and then started having problems? Assuming all of the normal 3CX stuff checks out, I'm leaning towards the firewall being the issue. Also, you mentioned you ran wireshark and were able to capture the audio from the caller but not the agent (weird). but you don't mention if the audio was missing in the capture as well or if it was there.