Iñaki Baz Castillo writes:
Yes, but there are problems too if a registered user has killed him softphone or PC without letting it sending the un-REGISTER. In that cases other user calling to him receive an infinite "Trying", while with my suggestion of un-register, callers would see "not found".
then you need to improve your script. set invite timer for no (provisional) response to a short value. then in failure route do whatever the user wants, for example, return "480 temporarily unavailable" or redirect the caller somewhere else.
-- juha