Server placement for enhancing the interactivity of large-scale distributed virtual environments

Distributed Virtual Environments (DVEs) allow many simultaneous human users to interact with each other in shared, 3D virtual worlds. The interactivity of a DVE is of crucial importance, as its success greatly depends on users' perceptions when interacting within the virtual world. In this paper different from traditional application-centric approaches like dead reckoning, we propose a network-centric approach to enhance the interactivity of DVEs by directly reducing the network latencies in client-server communications. We consider a key problem with this approach, termed the server placement problem. Generally, this problem concerns how to place servers in the network to reduce client-server communication latencies. We then suggest several degree-based server placement approaches. Extensive simulation studies using realistic models have shown that appropriate server placement is very effective in enhancing the interactivity, of large-scale DVEs.