Adaptation Layer Translator (ALX) Design and Application

High quality video-conferencing is an efficient tool for interactive scientific collaboration in the research community, especially for researchers separated by substantial distance. With the wide deployment of broadband wide area IP networks such as the Internet2, there is an increasing demand for improved remote collaboration with these networks. In order to make the high quality video-conferencing toolkits that work well on local high-speed networks available over wide area IP networks, issues that are usually insignificant on local area networks must be considered. To this end, we have developed a device called an Adaptation Layer Translator (ALX) in order to address these issues and solve the problems associated with real-time video and audio transmission over wide area IP networks. The ALX adopts the adaptation layer translation technique to transmit multimedia traffic on local ATM networks through the broadband wide area IP networks. Large buffers and careful handling of lip-synch are employed to counter the long round-trip time and big fluctuations. The conference control protocol based on a channel rotation scheme is developed to coordinate the participants in an ALX-based conference. The ALX is also designed with the capabilities to adapt to heterogenous network environments at different deployment sites.