In a communication network structure, a communication network system using the communication network structure and a communication method for the communication network system, a plurality of user stations which are connected to one another through bidirectional communication means, and at least...http://www.google.de/patents/US5822529?utm_source=gb-gplus-sharePatent US5822529 - Distributed bidirectional communication network structure in which a host station connected to a plurality of user stations initially assists only in setting up communication directly between user stations without going through the host station 
