Hugh Waite writes:
I can't remember if branches using TCP that fail to establish a connection generate a 408 Timeout response or not (eventually).
no, i get this immediately when t_relay() fails to dead tcp destination:
SIP/2.0 477 Unfortunately error on sending to next hop occurred (477/TM).
If an immediate error is detected, like a TCP connection failure, perhaps a different 'fake' reply, similar to timeout could be generated and sent through the reply handling code for that UAC. This would trigger the branch_failure route and also the failure route when all replies are received, allowing faster response handling instead of timeouts.
yes, if tm:branch-failure cannot be activated directly from tm [t_fwd.c:1520] then perhaps a fake reply can be generated from there. that, however, goes beyond my knowledge of tm module.
-- juha