A recursive overlay multicast algorithm for distribution of audio streams in networked games

This paper aims to provide a fast multicast algorithm among a set of distributed proxies to enable the creation of realistic audio for networked games. We assume that each proxy is responsible for a group of clients. The proxy receives the audio packets from its clients and multicasts this audio to every other proxy that requires this audio for any of its attached clients. In crowded virtual environments, the number of multicast trees could be quite large and these undergoes continuous change as the avatars move in and out of each others hearing range. To reduce the effect of overhead traffic caused by a large number of unicast flows, we propose the use of (i) coordinate-based clustering of the servers to reduce the number of packet replications required at each server; and (ii) a recursive multicast tree construction with minimal control overhead and reconfiguration complexity. We present simulation results for a crowded networked environment and evaluate the effectiveness of our algorithm in terms of path delay in comparison with the shortest unicast delay paths.