Method and multimedia transmission stream system

This data flow transmission method of a multimedia session between a first and a second terminal (1, 2) through a network (3) comprising a telecommunication heart (4) network comprises the determination by the modules (20 , 20 ', 20 ") edge, access points to said heart (4) network, the routing topology and link state (7, 16) of the network, the determination of session parameters, the selection modules (20 ', 20 ") edge of input and output of the heart (4) for said network flow, the predetermination of a path between the modules (20', 20") of the edge of input and output for all streams of the session, the establishment of resources along the way, the definition of routing rules from modules (18) routing located along said path, and transmission flows only by said path.