Client assignment algorithms for enhancing interactivity in distributed virtual environments

Abstract

In recent years, advances in networking technolo- gies, graphic cards and CPU power have enabled the rapid devel- opment of Distributed Virtual Environments (DVEs). Prominent applications of DVEs include online games, military simulations, collaborative designs, virtual shopping mall, etc. To support large-scale DVEs with real-time interactions among thousands or more distributed clients (users), a geographically distributed server architecture (GDSA) is generally needed, and the virtual world can be partitioned into several distinct zones to distribute the load among the servers. Due to the geographic distributions of clients and servers in such architecture, it is essential to efficiently assign participating clients to servers to enhance users' experience in interacting within the DVE. In this paper, we formulate this client assignment problem, and show that it is NP-hard. Several heuristic assignment algorithms are then devised and evaluated via extensive simulations with realistic settings. We find that, even under heterogeneous environments like the Internet where accurate input data for the assignment algorithms are usually impractical to obtain, our greedy algorithms are still beneficial to DVE performance.