Development of a VoIP application
- Establish connection when both users call eachother instead of both having to confirm it;
- Implement initial REGISTER rejection and provide challenge for credentials;
- One user may call other (which is registered) without itself registering;
- Place calls on hold by accepting other calls while one is ongoing;
- Cancel registration by sending another REGISTER request;
- Lacking ACK from Alice after receiving ACCEPT from Bob, as described in RFC 3665;
- Tidy terminal mess (maybe log the packets instead of printing them);
- Tidy application interface (it's still kinda counter-intuitive), by running an input loop.