One of my users (the one who uses the phone the most) has reported several times since switching to VoIP that sometimes calls are getting disconnected unexpectedly. Since this is intermittent, the only way I can debug it is looking through the log. Here are the entries when today's call got disconnected (I changed his number to 4085551212 in this log):

2013-03-21 09:53:47.420473 [DEBUG] switch_core_session.c:975 Send signal sofia/phone/sip:4085551212@192.168.4.244 [BREAK]

2013-03-21 09:53:47.440473 [DEBUG] switch_channel.c:3011 (sofia/phone/sip:4085551212@192.168.4.244) Callstate Change ACTIVE -> HANGUP

2013-03-21 09:53:47.440473 [NOTICE] sofia.c:711 Hangup sofia/phone/sip:4085551212@192.168.4.244 [CS_EXCHANGE_MEDIA] [NORMAL_CLEARING]

2013-03-21 09:53:47.440473 [DEBUG] switch_channel.c:3034 Send signal sofia/phone/sip:4085551212@192.168.4.244 [KILL]

2013-03-21 09:53:47.440473 [DEBUG] switch_core_session.c:1310 Send signal sofia/phone/sip:4085551212@192.168.4.244 [BREAK]

2013-03-21 09:53:47.440473 [DEBUG] switch_ivr_bridge.c:597 BRIDGE THREAD DONE [sofia/phone/sip:4085551212@192.168.4.244]

2013-03-21 09:53:47.440473 [DEBUG] switch_ivr_bridge.c:622 Send signal sofia/external/+19259639530@flowroute.com [BREAK]

2013-03-21 09:53:47.440473 [DEBUG] switch_core_state_machine.c:480 (sofia/phone/sip:4085551212@192.168.4.244) State EXCHANGE_MEDIA going to sleep

2013-03-21 09:53:47.440473 [DEBUG] switch_core_state_machine.c:415 (sofia/phone/sip:4085551212@192.168.4.244) Running State Change CS_HANGUP

2013-03-21 09:53:47.440473 [DEBUG] switch_core_state_machine.c:676 (sofia/phone/sip:4085551212@192.168.4.244) State HANGUP

2013-03-21 09:53:47.440473 [DEBUG] mod_sofia.c:503 Channel sofia/phone/sip:4085551212@192.168.4.244 hanging up, cause: NORMAL_CLEARING

I'm assuming this mean that the internal user (who's phone is 192.168.4.244) hung up, but he tells me he didn't. He was just talking and then there was no answer. I'm not sure where to look next. Any idea?

Steve