One-way audio every other random call

This is a Cisco or a Velo Cloud issue for the end client. The symptom was the calls would be answered on a analog multi line phone system for a auto parts store.

The company is huge and has hundreds of these automotive parts stores around the country. The symptoms were crosstalk and calls having one way audio. The crosstalk was taken care of. The one-way audio what occur when the call would come in and the manager or a employee would answer the call on all lines. A two-way conversation would start between the counter Clerk and the customer it would last for maybe 5 or 10 seconds. The audio coming in from the customer would go silent. The customer would hear the clerk talking to them. If the customer stayed on for probably 20 seconds or longer the streaming RTP data duplex data would resume. Sometimes the audio would just a one-way and the clerk at the counter would have to hang up.

It’s happening quite frequently. The demarcation point terminates into a Velo cloud and then develop Cloud hooks up to the Cisco router. The outputs of the Cisco router uses in FX s signaling card. The signaling with the terminate onto a 66 touchdown and of course all the line one would be looped to all the phones. I fixed the crosstalk but the dropped audio continues. Would that be a function of the Cisco router causing this? Or The Velo cloud?

I’m not at the site anymore I left two days ago but I don’t want to be in a position where I’m trying to troubleshoot something that’s nearly impossible. I thought if a Wireshark laptop could be inserted between the Villa cloud and the Cisco router to see if there’s any dropped RTP packets. I’m trying to figure out the theory other than one way Nat issues would cause this.