Control mechanism for large-scale virtual environments

In this paper we propose a control mechanism called a three-level consistency approach to maintain information consistency and to control the dynamic shared state in a web-based large-scale virtual environment. The approach consists of three major techniques for dynamic shared state maintenance-the shared repository technique, the blind broadcasting method, and the dead reckoning model. Depending upon the number of participants and system load, the approach can automatically switch from one level to another level based upon some predefined criteria to maintain maximum performance. We further classify the shared objects into three types of general behaviors to ht the proposed consistency approach in order to minimize the required network traffic and reduce update frequency. The Poisson process is used to establish the performance evaluation model. Comparisons of the performance of the proposed approach and the shared repository technique were conducted. Experimental results show that the proposed approach is very effective for maintaining low network latency over a wide range of participants and performs much better than the shared repository technique. (C) 1999 Academic Press.