Video Conferencing

ANSPAG has a major Network Testbed facility which provides a valuable pratical environment for network research. However, it is often the case that other networking experts are located elsewhere and find it difficult to get to the lab. ANSPAG engineers were getting frustrated by this and kept wishing they could just lean over and have a chat with their colleague. That is where the concept of a "Virtual Window" comes in.

Video-Conferencing has been around for some time now and could even be said to be "maturing" as a technology. Typically video-conferencing requires a fairly powerful PC, into which is installed some "hardware". A camera typically sits on top of the computer screen, with a microphone mounted nearby. It is necessary that the person you are video-conferencing with has the same equipment and it is generally necessary that it is manufactured by the same people. The video and audio are processed into a stream of digital information, which is sent across a communication line to the other PC, which then decodes and assembles the information back into video and audio streams. The difficulty is of course to synchronise the audio and video and also to maintain a high quality of picture and sound.

Video conferencing at Interact '96

Because of the high volume of data transmitted during a video-conference, relatively high bandwidth is required, typically a 64kbps ISDN line is sufficient as a minimum. This bandwidth requirement may well fall over time as the compression and transmission technologies improve.

ANSPAG's interest in Video-conferencing is largely based around the application of Asynchronous Transfer Mode technology to improve quality-of-service (QOS). Video-conferencing is used extensively as a test application on the ANSPAG Network Testbed and Demonstration Facility. It is particularly useful as a test application, since deterioration in QOS is easily measured and detected by the human senses. It is also particularly well suited for measuring the traffic flow of ATM cells, and thus for measuring the dynamics of ATM technology itself.

ANSPAG operates a number of video-conferencing units and regularly uses them for interstate and intrastate conferences and meetings. The Video Communications group at Monash University, which is colocated with ANSPAG in the Centre for Telecommunications and Information Engineering (CTIE), has developed a software based Video-Conferencing system, which removes the need for expensive "hardware" purchase and installation. Partners are currently being sought for commercialisation.

For more information on our video-conferencing activities, contact us.