Centralized versus distributed schemes for videoconferencing

Videoconferencing has become one of the major applications which is driving new computing and communication technologies. Solutions for the circuit switched and packet-based networks differ considerably. The H.320 ITU Standard has defined a solution for videoconferencing over N-ISDN. This standard advocates a centralized approach to multiparty conferencing based on a multipoint control unit (MCU). Various aspects of the H.320 standard are clearly reusable in packet-switched environments while others are not. In this paper we examine the differences between a centralized MCU multiparty conference approach and a distributed multiconference approach which leverages some of the capabilities of the packet-based networks. Each approach has distinct advantages and disadvantages. We discuss these and present a distributed Multimedia Multiparty Teleconferencing system we have implemented.