[Freeswitch-users] How to tell if 100 Trying received

[John Dalgliesh]

Hi,

I am trying to use FS to make outgoing SIP calls. I have a number of 
gateways that can make the call. However, if one of them is down or has 
some other problem then I would like to detect that quickly.

I intended to use the provisional '100 Trying' message for this... if it 
hasn't been received in a couple of seconds then go on and try the next 
gateway.

But I can't find a flag/event/state which corresponds to receipt of this 
message. Can anyone tell me where I should be looking? I put a debug print 
in sofia_event_callback for every event but there doesn't seem to be one 
fired for this condition.

Thanks in advance.

{P^/
John