Once user pick up the phone, a sip- 200 OK will be redirected to the caller, then SDP goes with
RTP related info, and then RTP session established, communication begins. I guess that's roughly
how it goes. Based on keywords mentioned above, you can check on this diagram
cheers,
--
“This life always seems to me to be a continuing process of education
and development. What we are preparing for, none of us can be sure.
But, that we must do our best while we are here and develop all our
capacities is absolutely certain. We face whatever we have to face in
this life. And if we do it bravely and sincerely, we’re probably
accomplishing that growth which we were put here to accomplish.”
~Eleanor Roosevelt