PRASAD CALYAM, CHANG-GUN LEE
Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH 43210 E-mail: pcalyam@oar.net, cglee@ece.osu.edu

In this paper, we present our research on characterizing voice and video traffic behavior in large-scale Internet Videoconferencing systems. We built a voice and video traffic quality measurement testbed to collect Videoconferencing traffic traces from several sites all over the world that were connected to our testbed via disparate network paths on the Internet. Our testbed also featured the H.323 Beacon, an H.323 session performance assessment tool we have developed, and various other open-source and commercial tools. Our findings obtained by analyzing the collected traffic traces demonstrate the impact of: 1) end-point technologies that use popular audio and video codecs and 2) network health status that is characterized by the variations of delay, jitter, lost and re-ordered packets in the network, on the end-user perception of audiovisual quality. The perceptual data used in our analysis includes both objective and subjective quality measures. These measures were collected from our testbed experiments for a few sample tasks involving various levels of human interaction in Internet Videoconferences.