Am Using Pjsip libraries for SIP implementation . Using Pjsip lib i can able to make IP calls perfectly . My problem is While I Make call if other End User Decline/not Reachable or No answer ,My call will connect with Voice mail and get 200k(call connected state) from sip server as same like other end user Answering call.
Not Reachable Case i can differentiate 200 ok By missing 183 Session Progress Message. But noanswer and decline case I couldn't get the actual State of call .
is any way to find call connected state and Voice mail connected state ?
2
votes
1 Answers
2
votes
There isn't any one way of a user agent knowing it has reached a voicemail server versus a person answering.
Usually what will happen is that your user agent will send an INVITE to a From URI, and some proxy responsible for that URI will fork the INVITE to the various user agents the remote party uses: her phone, her voicemail service, and so on. The first user agent to return a 2xx response sets up the call.
You will however always know to which user agent you have connected, in the Contact header of the 200 OK.
Presumably a voicemail server will indicate in its SDP offer/answer that while it accepts certain incoming media streams, it will not send anything, by marking the stream with an a=recvonly attribute (See RFC 3264).
