I have a Cisco 9971 Phone registering via SIP to a CUCM 7.1.3 Server. I am running the latest software code, available from Cisco 9.0.3. I am having random issues as far as one way audio, after an outbound call is made at exaclty 15 minutes, I cannot hear my calling party, but they can hear me. This problem is only intermittant. I do see the call active on my g/w, and when I look at call statistics on the phone I am rx and tx rtp packets. Has anyone experienced this problem ?