Dedug SIP trunk from CM to CUBE

From TAC

The link below outlines how to enable detailed traces on CUCM cluster and collect them:
Set Up Cisco CallManager Traces for Cisco Technical Support:http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_tech_note09186a0080094e89.shtml

Now this is the best bit of code i have seen in a long time! Enable SIP debugs, stores them in a txt file on the flash and when the error condition “503 Service Unavailable” happens do some show cmd and turn debugs off.

conf t
service timestamps debug datetime msec localtime
service timestamps log datetime msec localtime
service sequence-numbers
no logging queue-limit
logging buffered 12000000
no logging rate-limit
no logging console

event manager applet Capture_503
event syslog pattern "503 Service Unavailable"
action 0.1 syslog msg "503_Error_has been_Encountered"
action 1.0 cli command "ena"
action 1.4 cli command "show clock | append flash:503.txt"
action 2.0 cli command "show proc cpu sort | append flash:503.txt"
action 3.0 cli command "show log | append flash:503.txt"
action 4.0 cli command "show voice call sum | append flash:503.txt"
action 5.0 cli command "show voice call active voice br | append flash:503.txt"
action 6.0 cli command "un all"
end

clear log
y
debug ccsip mess
debug voip ccapi inout

once you encounter an error condition copy the file from flash to PC

copy flash tftp
503.txt
"ip address of your tftp server"