Network architecture for data transmission

[Subject] The contents distribution network accompanied by a multicasting attribute is offered by the client side which operates with reduction bandwidth. [Solution means] Demanded contents like multimedia contents are given in the suitable format for the transmission on the existing unicast communication link, and are changed into the multicasting format for local distribution. By this an application provider, The single unicast stream of contents can be transmitted to the client side media server in a Local Area Network (LAN), and two or more users who use a multicasting transmitting format and show interest in LAN can be supplied widely. Sharp reduction of a bandwidth demand is rather brought about by giving single unicast transmission to LAN rather than supplying each user within LAN using a contents stream for exclusive use. [Selection figure] Fig. 1