Measuring and optimizing delays in video conferences

In multi-party video conferencing applications, each terminal needs to transmit its video/audio data to all other participating terminals. In production systems, centralized servers are frequently employed to relay the traffic and process data streams. We aim to devise effective algorithms to choose the server location to minimize the sum of pairwise delays, given the locations of participating terminals. We will use PlanetLab nodes to measure the delays of Internet hosts at different geographic locations to several fixed probe points, representing each host as a vector in a delay space. Then we will use the measured delay vectors of the participating hosts as the input to our optimization algorithm, which will produce the optimal location of servers in the delay space. The real servers that are nearest to the computed optimal solution in the delay space will be chosen as the final server location. The use of PlanetLab nodes is to verify the feasibility of the above idea for choosing server locations in multi-party video conferencing.