Update schedules for improving consistency in multi-server distributed virtual environments

Abstract

Distributed Virtual Environments (DVEs) have been widely used in online games, military training and collaborative engineering applications, etc. In DVEs, the primary task is to maintain a consistent view of the virtual world among all users. Multi-server architecture has been shown to have good scalability to support a large population of users in DVEs. However, servers can still get saturated with network bandwidth due to several reasons. In this case, state updates cannot be disseminated timely and the consistency of the virtual world cannot be guaranteed. This paper investigates update schedules to prioritize state updates from a global perspective for improving consistency in multi-server DVEs where each server has a limit on upload bandwidth. Using time–space inconsistency (TSI) metric, we analyze the problem using Lagrange Multipliers for a DVE in an ideal situation with unchanged configurations and the results are then used to develop an updating algorithm in practical systems. Experimental results show that the proposed algorithm significantly improves the consistency compared to other existing update algorithms.