This is an abstract question on how the SIP protocol works. Let us say I have a SIP server (Asterisk/Yate). And I have two Android devices that wish to connect to each other to have an audio call. ( I am looking for a purely VoIP call, no need for telephone numbers or carrier information).
How would this work? Do the packets have to pass through the server? or does the connection happen between the end-points. If the packets has to pass through the server, does the SIP server also provides profiles, or do profiles have to be created by a third party?
I need to understand how the scheme works in order to start planning building the system.
I have read lots of technical documentations, but none show an abstraction of the system. If you can provide me with resources, that would be great too.
Thanks