I have one-way-voice issues on some calls, originating on two different gtw`s (both MGCP, E1)!
Let say, one of ten calls experience this problem - call is one-way-voice - from ip phone to gtw ok, but from gtw to ip phone there is only silence! when call is retryed everything is ok!
Interesting is that rtp payload in packets from gtw to phone consist of all FFFFF`s, and there is no lost of packets!
Here is wireshark capture, 10.250.230.6 is IP of a gateway. Can somebody help please?