Adaptive Handling of the Bandwidth Heterogeneity in Collaborative Virtual Environments

This article proposes a mechanism for improving the collaboration in a distributed virtual environment with heterogeneous networking, adapting the operation of the virtual environment, to the varying conditions of the network. Normally, a user who participates in a virtual environment with other users, does not have to his disposition the ideal network conditions for the transmission and reception of the application data. The fundamental idea is that once a station detects the diminution in the available network bandwidth, it starts predicting, by means of Dead Reckoning, the following movements of the other users with the purpose of maintaining the consistency between its virtual world and worlds of the other users. In a client-server environment, the server will send messages to the stations of the users who participate in the virtual world, depending on the conditions of each one of them, grouping the stations in multicast groups according to the speed of the incoming messages to each node, as implemented first in the Switchboard Architecture, developed by one of the authors in his doctoral dissertation. In the work describe in this paper, experiments were conducted both in local area and wide area networks, simulating adverse networking conditions that lead to a reduction in available bandwidth. Our experiments show that the combination of the Switchboard Architecture and the Dead Reckoning algorithm, allow for a significant reduction in network bandwidth, while maintaining the usability of the networked environment under adverse network conditions.