Patent ID: 7860003

Claim:
A system for managing communication sessions between first terminals adapted to send streams of audio data and/or video data and/or data during said sessions and second terminals accessible via an external data transmission network, the first terminals being connected to a stream concentrator forming a gateway to the external network, wherein the streams of data sent by at least some of the first terminals are coded by hierarchical coders, each hierarchical coder being adapted to encode a corresponding stream of data into a plurality of successive layers of coded data that give together a maximum bit rate of the corresponding stream of data, the plurality of successive layers corresponding to a plurality of hierarchy levels from a base hierarchy level defining a minimum quality of the corresponding stream of data up to a respective maximum hierarchy level defining a maximum quality of the corresponding stream of data, wherein the stream concentrator includes: means for determining, successively for each of the sent streams of data and among the corresponding plurality of hierarchy levels, a hierarchy level of coded data as a function of parameters relating to the number and nature of the sessions set up between the first terminals and the second terminals, wherein, for at least one of the sent streams of data, an intermediate hierarchy level that is lower than the respective maximum hierarchy level is determined, and means for processing the sent streams of data so that each of the sent streams of data is sent to the external network by the stream concentrator at the corresponding determined hierarchy level of data, wherein the at least one of the sent streams of data is sent at the determined intermediate hierarchy level that is lower than the respective maximum hierarchy level to change the bit rate of the at least one of the sent streams of data compared to the maximum bit rate and then, to size the sent streams of data to avoid congestion of the concentrator.