This briefly describes the call flow with SIP Headers and Tropo's webapi JSON communication.
1. SIP/2.0 100 Trying/INVITE ,
2. SIP/2.0 180 Ringing
3. JSON POST to the specified application's server (logged as "Sending TropoML")
4. JSON returned by application server to Tropo (unless your app server fails to process the request), logged as "Response from" and "Received new TropoML"
5. Then a SIP/2.0 200 OK is logged to show the call is connected.
If, for some reason, the call hangs up between the POST to server and the returned JSON (between steps 3 and 4), SIP/2.0 487 Request Terminated will be logged after "Sending TropoML", followed by the JSON being received by Tropo, and "Call disconnected while processing action"