A conferencing system for real-time, multiparty, multimedia services

In this paper, we describe a conferencing system designed to provide real-time, multiparty, fully interactive multimedia services. The requirements of multimedia conferencing service can be summarized as follows. First, there are a number of participants, and the number of participants varies dynamically for service duration. So there must be a provision which allows members to join and leave a conference. Second, each multimedia data has its own characteristics, and they have very close relationship to one another. So, the Quality of Service(QoS) requirements of each media must be satisfied separately, and at the same time their relationship must be maintained at the playback time. For example, the audio and video data must be synchronized at the playback time. Considering above requirements, we designed a multiparty, multimedia conferencing system. It is mainly composed of two control entities: group manager and media manager. A group manager controls and maintains the participants group according to group attributes, and a media manager performs call admission control according to its anticipation of network status at the call request time, and controls media data sending rate based on the receivers' periodic media reception quality reports. For more efficient control, we take into consideration the group characteristics in the media control algorithm. Feasibility has been confirmed by laboratory trials.