I am running into a strange issues from last week. Calls from carriers other than Verizon has no issues. It is only when someone using Verizon cell phones calls in, called party which is a Cisco phone can hear the caller but not the other way around and it happens almost 75% of the time. When calls are placed from the Verizon cell phone, I dont' hear the ring back tone nor the audio. I hear a very disturbing static noise. When it works for the 25% of the time, I hear the ring back tone as well as audio.
Opened a TAC case yesterday and the engineer did packet capture in the gateway. I was told that there are clear audio in the gateway (for the failed calls) but somehow they are failing to reach back to the caller (Verizon cell phone).
We use PRIs and connection between the gateway and CUCM is sip trunk.
Has anyone experienced similar issue? What was the solution if you did experience this issue?
Thanks
