Would be nice if it would be possible to - make timer of "default_timeout" reset to 0 when keep-alive reply is received from remote part of call leg, so that the timeout expires (triggering call termination) only if some call party gets offline (we don't want just to limit the duration of normal call, even if call parties don't send any new SIP requests); OR - make unresponsiveness of call parties to keep-alive messages (controlled with ka_timer, ka_interval parameters) lead to some action, like call termination.
Please advise if I miss something, and how to implement this better. Thanks in advance.