Making Networked Virtual Environments Work

Abstract

Collaborative virtual environments (CVEs) are a promising technology enabling remote participants to share a common place through three-dimensional graphical scenes. Within the COVEN project (Normand, 1999), we have run prolonged series of Internet trials that have allowed us to gather valuable data to formulate usability guidelines and networking requirements. However, running such trials in a real setting and making sure that the application and networking infrastructures will be stable enough is still a challenge. In this paper, we describe some of our experiences, together with the technical choices that have permitted many hours of successful Internet trials. We also make a thorough analysis of different correlated logging data. This analysis allows us to propose and con rm a model of a CVE application's network behavior, together with a number of interesting results that disprove some common assumptions. Furthermore, we use the model and the logging data to highlight the bene ts of IP multicasting and for predicting traf c behaviors and bandwidth use on top of different logical network topologies.

A Study of Event Traffic During the Shared Manipulation of Objects Within a Collaborative Virtual Environment

“…This was chosen because it is an established testbed for experimentation of collaboration in virtual environments and, after three major revisions, remains an effective benchmark Greenhalgh et al, 2001;Schroeder et al, 2001;Steed, Mortensen, & Frécon, 2001;Mortensen et al, 2002). DIVE version 3.3.5 was used for all display devices.…”

“…Relevant examples are NPSNET (Macedonia, Zyda, Pratt, Barham, & Zeswitz, 1994), PaRADE (Roberts, Sharkey, & Sandoz, 1995), DIVE (Frécon & Stenius, 1998), MASSIVE (Greenhalgh, Purbrick, & Snowdon, 2000), CAVERNsoft (Leigh, Johnson, & DeFanti, 1997) and QUICK (Capps, 2000). Some studies have investigated the performance of communication infrastructures used to link training simulators (Wuerfel, 1998;d'Ausbourg, Bussenot, & Siron 2002), while other studies have investigated the network traffic generated by both social gatherings and teamwork activities (Roberts, Richardson, Sharkey, & Lake, 1998;Roberts, Strassner, Worthington, & Sharkey, 1999;Frécon, Smith, Steed, Stenius, & Stahl, 2001;Greenhalgh, Bullock, Frécon, Lloyd, & Steed, 2001;Leigh et al, 2001).…”

A new system architecture for crowd simulation

“…This scheme provides the highest level of load distribution. Although the first DVEs were based on centralized architectures, during the last few years architectures based on networked servers have been the major de-facto standard for DVE systems [17,11]. However, each new 5 avatar in a DVE system represents an increase not only in the computational requirements of the application but also in the amount of network traffic [23,22].…”

A Genetic Approach for Distributing Semantic Databases of Crowd Simulations

“…Distributed schemes like networked-server architectures [12,8,20] or peer-to-peer architectures [18,16,19] have been proved to improve the scalability of virtual environments through the use of different interconnected computers. In order to exploit the potential of such computer architectures, the software architecture must also be distributed.…”