A distributed latency-aware architecture for massively multi-user virtual environments

Massively multi-user virtual environments (MMVE) incorporate computer graphics, sound and haptics to simulate the experience of real-time interaction among multiple users in a shared three-dimensional virtual world. Such applications therefore deal with the distribution of updates among their users to provide them with a common sense of time and place while interacting in the virtual environment. This paper introduces a new distributed architecture for message exchange in MMVE applications. We propose the use of Hilbert space filling curve, due to its good locality preserving characteristics, as a mechanism for indexing users´ three dimensional locations to a one dimension. We also propose our novel routing strategy based on this architecture, which is executed among the points that are mapped over the Hilbert curve. Such hierarchical routing requires only few entries in the routing tables while it is guaranteed to converge in few steps. The routing procedure is based on guiding the packets to their destinations through traversing the Hilbert curve in tree format. A three dimensional Hilbert curve of order K can be described with a tree of K levels. In making a forwarding decision, a node finds the best neighbour that moves the message closer to its destination over this tree. This avoids the complexity of locating the points over the Hilbert curve as the mapping is actually performed throughout the routing process. The performance evaluation results show that the propose architecture can efficiently handle update exchange among MMVE users.