Is there a place I can readup on the remote-anything architecture? I see there's a master and slave -- do all the slaves dial out to the master and all slave-to

Is there a place I can readup on the remote-anything architecture? I see there's a master and slave -- do all the slaves dial out to the master and all slave-to-slave communication go through the master (like a turn server), or is it doing something more clever? In that case the master must be configured to accept connections