Customer provide a trace on the router side which include whole E2E trace, so it is very easy to analyze the call process.
The trace is attached.
According to the customer trace, we can find the ATS sent 500 mesaage at 36s. Before ATS send out the 500s, ATS didn’t get any response (such as 180/183) for the opposite. Acdoring to the clarificaiton of ATS timer design , ATS will release the invite with 500 message when it doesn’t get any response in 36s (which is configured by the following command).
+++ ATS/*MEID:51*/ 2011-05-05 15:22:40-04:00 DST
%%LST ITIMER: PID=198, YWLX=0, SEQ=3;%%
RETCODE = 0 Operation succeeded
The result is as follows:
PID = 198
Timer group = 0
Timer sequence = 3
Timer value/second = 36
(Number of results = 1)
Ask customer to help checking the PSTN side, and see that PSTN is outage, and can not make any response for any call.