I'm using an Avaya 9620L phone with an IP500 V2 through a hardware VPN tunnel. The phone will connect and operate properly, but during calls the audio will intermittently cut out (like a bad cell connection). Some calls are worse than others. I’ve checked the call information during a call and there are no dropped packets. I’ve currently got that extension set to the system default for codecs. I’m looking for how to reduce or eliminate the audio cut-out.