A cheat sheet for anyone trying to control FreeSWITCH bridge behaviour if you’re trying to move calls around if not answered / responded to:

originate_timeout

How long to wait for any response to from the remote peer (100 TRYING, 180 RINGING, etc).

This is useful for knowing when to give up and try a different peer as this peer is dead.

originate_retries

How many times to retransmit the INVITE if no 100 TRYING / 180 RINGING is received.

Like originate_timeout, this is handy for giving up sooner when a peer is dead and moving onto others.

progress_timeout

How long we wait between sending the SIP INVITE before we get a 180/183 before we give up.

This is handy to find out if the remote end isn’t able to reach the endpoint you’re after (page the UE in a cellular context).

bridge_answer_timeout

How long do we wait between the INVITE and a 200 OK (Including RINGING) – This is useful for “no answer” timeouts.

If you want to know why a bridge failed, ie no answer timeout reached, error on the remote end, etc, we can see why with the following variable:

variable_last_bridge_hangup_cause: [PROGRESS_TIMEOUT]

Which will allow you to tell if it’s no answer or progress timeout to blame.