Isidor Kouvelas

Successful multiparty audio communication over the Internet

The Internet was once perceived as a computer network used by researchers to transfer files and send text messages. Today, more users are becoming aware of its potential as a general communication network. Multicast conferencing over the Internet has the potential to offer low-cost real-time multimedia solutions to a wide range of user groups, provided that sufficient audio quality can be sustained. C ommercial interest in Internet audio has focused primarily on point-to-point applications such as Internet telephony, which provides roughly the same functionality as Public Switched Telephone Networks (PSTNs) over a computer network. The second focus of Internet audio developers has been download-ing audio files—typically from a WorldWide Web server—for playout on a remote users workstation [9]. Multicast conferencing [1], on the other hand, allows real-time multiway audio and video communication over the Internet and is now moving from the pilot stage [7] to a usable service in countries like the U.K. and the U.S. Multicast audio allows groups of users to participate in real-time, simultaneous audio conferences, supporting communication that goes beyond the possibilities of telephony or broadcast technology. Since the multicast backbone (Mbone—an overlay over the Internet [7]) can also support video and shared workspace, collaboration environments can be tailored to support the requirements of many distributed user groups. Another important benefit, particularly for applications such as distance education, is that multicast conferencing costs a fraction of the cost of other solutions. While video and shared data are essential to many distributed tasks, audio of sufficient quality is a necessary condition for almost any successful real-time interaction. Therefore, ensuring sufficient audio quality is a major stepping stone for realizing the potential of multicast conferencing.