Model and implementation of distributed multipoint control unit

Aiming at the issues existing in centralized multipoint control unit (MCU), such as concentrated traffic load, limited scale, poor extensibility and faults tolerance and so on, a distributed MCU model is proposed. It utilizes an unicast and multicast data transmission strategy, so that not only can it transmit the media stream across sub networks, but also can decrease the data traffic dramatically. Some performances of distributed MCU, including the scale of group communication and fault tolerance and recovery, are analyzed in detail. The proposed model is already tested and applied to the real-time tele-teaching system named Smart-Real Class. It is shown that the model can support larger scale group communication, balance the communicative traffic among MCUs, and has the ability to tolerate and recover the fault of any MCU.