Multiple LAN Internet Protocol Converter (MLIC) for Multimedia Conferencing

Multimedia conferencing over multiple Local Area Networks (LAN), or across a Wide Area Network requires the use of efficient multicast servers in order to function correctly. This paper presents a proposed Multiple LAN Internet Protocol Converter (MLIC) algorithm currently being implemented by the Network Research Group and Multimedia Research Labs Sdn. Bhd. for use with multimedia conferencing, to interconnect multiple wide area LANs using IP protocols. This proposed multimedia multicast router will allow multicast based multimedia traffic over ATM Networks like TEMAN (Testbed Environment for Malaysia Multimedia Applications and Networking) and APAN (Asia Pacific Advanced Networks). Existing wide-area multimedia conferencing architectures are designed using proprietary systems and routers for wide area multicasting. With MLIC, a distributed approach using off the shelf hardware is proposed. MLICs maintains the full duplex interaction between active multimedia conferencing clients via multicasting via IP tunneling to provide a seamless ‘virtual multicast network.’ In addition, multimedia streams may be compressed in order to accommodate the lower bandwidths available on wide area links. An algorithm for configuring the MLICs during conference initiation and termination is presented in this paper. In addition, the network bandwidth requirement of full duplex multimedia conferencing is analyzed. *This research project is funded by IRPA and MLabs Sdn. Bhd. and is supported by TEMAN and APAN. 1. MULTIMEDIA CONFERENCING USING MULTICAST Traditional multimedia conferencing architectures required dedicated equipment for both multimedia capture and display, as well as dedicated high bandwidth links between participating sites in order to deliver the necessary bandwidth and performance requirements for the users. Such multimedia conferencing systems are beyond the reach of many users. However, with the widespread adoption of Internet Protocol (IP)-based networks around the world, an open network for multimedia conferencing is now feasible. If the user is willing to put up with the lack of service guarantee inherent in IP-based networks, the use of IP-based protocols for wide-area communications is a much more cost-effective solution. Nonetheless, the network bandwidth requirements of multimedia conferencing would be overwhelming if each participant in the multimedia conference is expected to establish a link with every other participant. This leads to the N*(N-1) combinatorial explosion of network links needed to keep each participant in a conference in synchronization with the other participants. In addition, the timing jitter between different participants would have a high degree of variation since each participant node has to transmit the same data to all other participating nodes. The architecture would break down over a large number of distributed participants, such as in the case of widearea multimedia conferencing. Fortunately, the shared-medium nature of current Local Area Networks (LAN) can be exploited to minimize the impact of multimedia conferencing. If the multimedia conference were confined to a single LAN, then each participant node would only need to transmit one copy of the information via multicasting, which is