I have an Asterisk host connected to a T1 facility, and another Asterisk host connected via an IAX trunk in another location. I have Ring groups defined to ring a number of extensions at once. Intermittently when one of these ring groups is triggered, everyone that is on a phone call in the remote location is disconnected from their calls. I think I have narrowed this down a bit to the following log entries on the Asterisk host that has the trunks, and is connected to the other server VIA IAX trunks Jul 24 11:33:57 VERBOSE[1205]: -- Accepting call from '9529350635' to '7632353001' on channel 0/1, span 1 Jul 24 11:33:57 DEBUG[1205]: Enabled echo cancellation on channel 1 Jul 24 11:33:57 VERBOSE[13405]: -- Executing Dial("Zap/1-1", "IAX2/ucfrid/3001") in new stack Jul 24 11:33:57 VERBOSE[13405]: -- Called ucfrid/3001 Jul 24 11:33:57 VERBOSE[1171]: -- Call accepted by 67.88.180.210 (format ulaw) Jul 24 11:33:57 VERBOSE[1171]: -- Format for call is ulaw Jul 24 11:33:58 VERBOSE[13405]: -- IAX2/ucfrid/1 is ringing Jul 24 11:33:58 VERBOSE[13405]: -- IAX2/ucfrid/1 is ringing Jul 24 11:34:05 DEBUG[1171]: Raw Hangup 67.88.180.210:4569, src=2, dst=2 Jul 24 11:34:05 DEBUG[1171]: Raw Hangup 67.88.180.210:4569, src=2, dst=2 Jul 24 11:34:05 DEBUG[1171]: Raw Hangup 67.88.180.210:4569, src=2, dst=2 Jul 24 11:34:05 DEBUG[1171]: Raw Hangup 67.88.180.210:4569, src=2, dst=2 Jul 24 11:34:18 VERBOSE[13405]: -- IAX2/ucfrid/1 stopped sounds Jul 24 11:34:18 VERBOSE[13405]: -- IAX2/ucfrid/1 answered Zap/1-1 Jul 24 11:34:18 DEBUG[1171]: Ooh, voice format changed to 4 Jul 24 11:34:26 WARNING[1171]: Max retries exceeded to host 67.88.180.210 on IAX2/ucfrid@67.88.180.210:65065/2 (type = 6, subclass = 2, ts=958873, seqno=46) Jul 24 11:34:26 WARNING[1171]: Max retries exceeded to host 67.88.180.210 on IAX2/ucfrid@67.88.180.210:65065/2 (type = 6, subclass = 11, ts=958876, seqno=47) Jul 24 11:34:26 DEBUG[13402]: Didn't get a frame from channel: IAX2/ucfrid@67.88.180.210:65065/2 Jul 24 11:34:26 DEBUG[13402]: Bridge stops bridging channels IAX2/ucfrid@67.88.180.210:65065/2 and Zap/4-1 Jul 24 11:34:26 DEBUG[13402]: Set option AUDIO MODE, value: ON(1) on Zap/4-1 Jul 24 11:34:26 DEBUG[13402]: Hangup: channel: 4 index = 0, normal = 25, callwait = -1, thirdcall = -1 Jul 24 11:34:26 DEBUG[13402]: Not yet hungup... Calling hangup once with icause, and clearing call Jul 24 11:34:26 DEBUG[13402]: disabled echo cancellation on channel 4 Jul 24 11:34:26 DEBUG[13402]: Set option TDD MODE, value: OFF(0) on Zap/4-1 Jul 24 11:34:26 DEBUG[13402]: Updated conferencing on 4, with 0 conference users Jul 24 11:34:26 DEBUG[13402]: Set option AUDIO MODE, value: OFF(0) on Zap/4-1 Jul 24 11:34:26 DEBUG[13402]: disabled echo cancellation on channel 4 Jul 24 11:34:26 VERBOSE[13402]: -- Hungup 'Zap/4-1' Jul 24 11:34:26 DEBUG[13402]: Exiting with DIALSTATUS=ANSWER. Jul 24 11:34:26 VERBOSE[13402]: == Spawn extension (longdistance, 918774263777, 1) exited non-zero on 'IAX2/ucfrid@67.88 .180.210:65065/2' Jul 24 11:34:26 DEBUG[13402]: We're hanging up IAX2/ucfrid@67.88.180.210:65065/2 now... Jul 24 11:34:26 VERBOSE[13402]: -- Hungup 'IAX2/ucfrid@67.88.180.210:65065/2' Jul 24 11:34:30 VERBOSE[1205]: -- Channel 0/1, span 1 got hangup Jul 24 11:34:30 DEBUG[13405]: Bridge stops because we're zombie or need a soft hangup: c0=Zap/1-1, c1=IAX2/ucfrid/1, flags : No,Yes,No,No This is extremely intermittent, and otherwise the system works just fine. The above shows a call coming into an a number. The extension was in use, and then the system just seemed to tear down the whole IAX trunk. HFC :