A multi-server architecture for distributed virtual walkthrough

ABSTRACT

CyberWalk is a distributed virtual walkthrough system that we have developed. It allows users at different geographical locations to share information and interact within a common virtual environment (VE) via a local network or through the Internet. In this paper, we illustrate that when the number of users exploring the VE increases, the server will quickly become the bottleneck. To enable good performance, CyberWalk utilizes multiple servers and employs an adaptive data partitioning techniques to dynamically partition the whole VE into regions. All objects within each region will be managed by one server. Under normal circumstances, when a viewer is exploring a region, the server of that region will be responsible for serving all requests from the viewer. When a viewer is crossing the boundary of two or more regions, the servers of all the regions involved will be serving requests from the viewer since the viewer might be able to view objects within all those regions. We evaluate the performance of this multi-server architecture of CyberWalk via a detail simulation model.

REFERENCES

• 1: Asheron's Call. Available at http://www.microsoft.com/games/zone/asheronscall/.
• 2: Todd Barron , Patricia Pizer, Multi-Player Game Programming with CDROM, Premier Press, Incorporated, 2001
• 3: C. Carlsson and O. Hagsand. DIVE - a Multi-User Virtual Reality System. In Proc. of IEEE VRAIS, pages 394--400, 1993.
• 4: Addison Chan , Rynson W. H. Lau , Beatrice Ng, A hybrid motion prediction method for caching and prefetching in distributed virtual environments, Proceedings of the ACM symposium on Virtual reality software and technology, November 15-17, 2001, Baniff, Alberta, Canada [doi>10.1145/505008.505035]
• 5: Boris Y. Chan , Antonio Si , Hong V. Leong, A Framework for Cache Management for Mobile Databases: Design and Evaluation, Distributed and Parallel Databases, v.10 n.1, p.23-57, July 2001 [doi>10.1023/A:1019297705159]
• 6: J. Chim, R.W.H. Lau, H.V. Leong, and A. Si. CyberWalk: A Web-based Distributed Virtual Walkthrough Environment. IEEE Trans. on Multimedia (to appear).
• 7: Jimmy H. P. Chim , Rynson W. H. Lau , Antonio Si , Hong Va Leong , Danny To , Mark Green , Miu Ling Lam, Multi-resolution model transmission in distributed virtual environments, Proceedings of the ACM symposium on Virtual reality software and technology, p.25-34, November 02-05, 1998, Taipei, Taiwan [doi>10.1145/293701.293705]
• 8: Tapas K. Das , Gurminder Singh , Alex Mitchell , P. Senthil Kumar , Kevin McGee, NetEffect: a network architecture for large-scale multi-user virtual worlds, Proceedings of the ACM symposium on Virtual reality software and technology, p.157-163, September 1997, Lausanne, Switzerland [doi>10.1145/261135.261164]
• 9: D. J. DeWitt , S. Ghanderaizadeh , D. Schneider, A performance analysis of the gamma database machine, Proceedings of the 1988 ACM SIGMOD international conference on Management of data, p.350-360, June 01-03, 1988, Chicago, Illinois, United States
• 10: Diablo II, Starcraft. Available at http://www.blizzard.com/.
• 11: EverQuest. Available at http://everquest.station.sony.com/.
• 12: J. Falby, M. Zyda, D. Pratt, and R. Mackey. NPSNET: Hierarchical Data Structures for Real-Time Three-Dimensional Visual Simulation. Computers & Graphics, 17(1):65--69, 1993.
• 13: Thomas A. Funkhouser, RING: a client-server system for multi-user virtual environments, Proceedings of the 1995 symposium on Interactive 3D graphics, p.85-ff., April 09-12, 1995, Monterey, California, United States [doi>10.1145/199404.199418]
• 14: Chris Greenhalgh , Jim Purbrick , Dave Snowdon, Inside MASSIVE-3: flexible support for data consistency and world structuring, Proceedings of the third international conference on Collaborative virtual environments, p.119-127, September 2000, San Francisco, California, United States [doi>10.1145/351006.351027]
• 15: Hugues Hoppe, Progressive meshes, Proceedings of the 23rd annual conference on Computer graphics and interactive techniques, p.99-108, August 1996 [doi>10.1145/237170.237216]
• 16: M. Hori, T. Iseri, K. Fujikawa, S. Shimojo, and H. Miyahara. Scalability Issues of Dynamic Space Management for Multiple-Server Networked Virtual Environments. In Proc. of IEEE Pacific Rim Conf. on Communications, Computers and signal Processing, pages 200--203, 2001.
• 17: Rodger Lea , Yasuaki Honda , Kouichi Matsuda , Satoru Matsuda, Community Place: architecture and performance, Proceedings of the second symposium on Virtual reality modeling language, p.41-50, February 24-26, 1997, Monterey, California, United States [doi>10.1145/253437.253451]
• 18: Quake. Available at http://www.idsoftware.com/.
• 19: G. Singh, L. Serra, W. Png, and H. Ng. BrickNet: A Software Toolkit for Network-Based Virtual Worlds. Presence: Teleoperators and Virtual Environments, 3(1):19--34, 1994.
• 20: G. Singh , L. Serra , W. Png , A. Wong , H. Ng, BrickNet: sharing object behaviors on the Net, Proceedings of the Virtual Reality Annual International Symposium (VRAIS'95), p.19, March 11-15, 1995
• 21: Ultima Online. Available at http://www.uo.com/.

INDEX TERMS

Primary Classification:
  H. Information Systems
  H.5 INFORMATION INTERFACES AND PRESENTATION (I.7)
      H.5.1 Multimedia Information Systems
          Subjects: Artificial, augmented, and virtual realities

General Terms:
Experimentation, Performance

Keywords:
data partition and replication, distributed virtual environments, multi-server architecture