How to implement a peer-to-peer connection in a non-local network?

Question

Android

How to implement a peer-to-peer connection? For voice transmission. I tried freeswith, but it needs some kind of sip provider for it to work. I need a connection on a non-local network. And without intermediaries such as some providers, is it possible at all? The problem seems to be that peers can't find each other even if there is a central server and they get their real address through public stun servers. This real address changes all the time. How is it decided in general?

Answer 1

Peer-to-peer Internet connection is often difficult to implement due to the fact that each participant can be behind a certain number of firewalls and NAT, will require opening ports and forwarding them, or even the connection participant will have a "gray" address. In any case, you will need some intermediary server with a white address on the Internet, which can be Asterisk or FreeSwitch. Actually, they will act as a "sip provider", establishing a connection between 2 or more peers. Also, these PBXs have a setting according to which the server, after the initial contact between 2 participants, will try to connect their voice traffic directly, however, due to the already voiced problem with ptp to the Internet, this configuration may not work in "non- local networks".