Contents of /var/log/asterisk/full
Two Calls:

[2013-07-18 11:35:22]sip:*43@10.1.1.13 fails
[2013-07-18 11:36:45]sip:*43@Asterisk.TCLC.org succeeds
asterisk.tclc.org == 10.1.1.13




[2013-07-18 11:35:22] VERBOSE[17699][C-00000014] netsock2.c:   == Using SIP VIDEO TOS bits 136
[2013-07-18 11:35:22] VERBOSE[17699][C-00000014] netsock2.c:   == Using SIP VIDEO CoS mark 6
[2013-07-18 11:35:22] VERBOSE[17699][C-00000014] netsock2.c:   == Using SIP RTP TOS bits 184
[2013-07-18 11:35:22] VERBOSE[17699][C-00000014] netsock2.c:   == Using SIP RTP CoS mark 5
[2013-07-18 11:35:22] WARNING[17699][C-00000014] chan_sip.c: Got Siren7 offer at 24000 bps, but only 32000 bps supported; ignoring.
[2013-07-18 11:35:22] VERBOSE[24144][C-00000014] pbx.c:     -- Executing [*43@from-internal:1] Answer("SIP/200-00000013", "") in new stack
[2013-07-18 11:35:22] VERBOSE[24144][C-00000014] pbx.c:   == Spawn extension (from-internal, *43, 1) exited non-zero on 'SIP/200-00000013'
[2013-07-18 11:35:22] VERBOSE[24144][C-00000014] pbx.c:     -- Executing [h@from-internal:1] Hangup("SIP/200-00000013", "") in new stack
[2013-07-18 11:35:22] VERBOSE[24144][C-00000014] pbx.c:   == Spawn extension (from-internal, h, 1) exited non-zero on 'SIP/200-00000013'
[2013-07-18 11:35:28] WARNING[17699] chan_sip.c: Retransmission timeout reached on transmission 84601079-46ee-e211-9674-0026b99f8cdc@code.tryx.org for seqno 2 (Critical Response) -- See https://wiki.asterisk.org/wiki/display/AST/SIP+Retransmissions
Packet timed out after 6399ms with no response

[2013-07-18 11:36:45] VERBOSE[17699][C-00000015] netsock2.c:   == Using SIP VIDEO TOS bits 136
[2013-07-18 11:36:45] VERBOSE[17699][C-00000015] netsock2.c:   == Using SIP VIDEO CoS mark 6
[2013-07-18 11:36:45] VERBOSE[17699][C-00000015] netsock2.c:   == Using SIP RTP TOS bits 184
[2013-07-18 11:36:45] VERBOSE[17699][C-00000015] netsock2.c:   == Using SIP RTP CoS mark 5
[2013-07-18 11:36:45] WARNING[17699][C-00000015] chan_sip.c: Got Siren7 offer at 24000 bps, but only 32000 bps supported; ignoring.
[2013-07-18 11:36:45] VERBOSE[24246][C-00000015] pbx.c:     -- Executing [*43@from-internal:1] Answer("SIP/200-00000014", "") in new stack
[2013-07-18 11:36:45] VERBOSE[24246][C-00000015] pbx.c:     -- Executing [*43@from-internal:2] Wait("SIP/200-00000014", "1") in new stack
[2013-07-18 11:36:45] NOTICE[24246][C-00000015] channel.c: Dropping incompatible voice frame on SIP/200-00000014 of format ulaw since our native format has changed to (g722)
[2013-07-18 11:36:46] VERBOSE[24246][C-00000015] pbx.c:     -- Executing [*43@from-internal:3] Playback("SIP/200-00000014", "demo-echotest") in new stack
[2013-07-18 11:36:46] VERBOSE[24246][C-00000015] file.c:     -- <SIP/200-00000014> Playing 'demo-echotest.gsm' (language 'en')
[2013-07-18 11:36:59] VERBOSE[24246][C-00000015] pbx.c:   == Spawn extension (from-internal, *43, 3) exited non-zero on 'SIP/200-00000014'
[2013-07-18 11:36:59] VERBOSE[24246][C-00000015] pbx.c:     -- Executing [h@from-internal:1] Hangup("SIP/200-00000014", "") in new stack
[2013-07-18 11:36:59] VERBOSE[24246][C-00000015] pbx.c:   == Spawn extension (from-internal, h, 1) exited non-zero on 'SIP/200-00000014'