1. Director: Sheng-Wei Chen Presenter: Shun-Yun Hu

2. MMNet Intro Multimedia Networking and Systems Laboratory Established since 2006. Dr. Sheng-Wei Chen (Associate Fellow) Postdoc (1), Ph.D (5), RA (10) Main Research Areas: Internet Quality of Experience (QoE) Network Security Online Gaming

3. Research Areas Internet Quality of Experience (QoE) User satisfaction index & framework Packet rate adjustment for efficiency Network Security Quantify info leakage on social networks Phishing detection Online Gaming Efficient data transmission Game bots detection

4. Blizzard, World of Warcraft

5. America’s Army

6. Forterra Systems

7. Can we build a virtual environment with millions of concurrent users?

13. Na t i o n a l C e n t r a l U n i v e r s i t y Spatial publish subscribe (SPS) pub sub Point publication Area publication Point subscription Area subscription

14. 14 A simple solution (point-to-point) But…too many irrelevant messages N * (N-1) connections ≈ O(N 2 )  Not scalable! Source: [Funkhouser95]

15. 15 A better solution (client-server) Message filtering at server to reduce traffic N connections = O(N)  server is bottleneck Source: [Funkhouser95]

16. 16 Current solution (server-cluster) How to partition & balance load? Source: [Funkhouser95]

18. Load fluctuations

19. Density-aware Partitioning

20. 20/ Na t i o n a l C e n t r a l U n i v e r s i t y Voronoi-based Overlay Network (VON) Boundary neighbors New neighbors Non-overlapped neighbors Voronoi diagrams identify boundary neighbors for neighbor discovery

21. Dynamic Load Balancing

22. Overlap in neighbor regions

23. root A B C D E F G H I J K M N O P Q L

24. Conclusion Potential Applications Voice communication 3D content streaming State management Future Works Area publications Experiment with millions of entities Cloud & P2P deployment

25. References [1] Shun-Yun Hu, Jui-Fa Chen and Tsu-Han Chen, "VON: A scalable peer-to-peer network for virtual environments," IEEE Network, vol. 20 no. 4, Jul./Aug. 2006, pp. 22-31. [2] Yeng-Ting Lee and Kuan-Ta Chen, “Is Server Consolidation Beneficial to MMORPG? A Case Study of World of Warcraft,” in Proc. IEEE Cloud, 2010. [3] Shun-Yun Hu and Kuan-Ta Chen, "VSO: Self- organizing Spatial Publish Subscribe," in Proc. Fifth IEEE Self-Adaptive and Self-Organizing Systems (SASO 2011), Oct. 2011.

26. Thank You Q & A

27. Static vs. dynamic partitioning

28. Effect of churn on consistency

29. 29 Voronoi Diagram 2D Plane partitioned into regions by sites, each region contains all the points closest to its site Neighbors Site Region

30. 30 Design Concepts Identify enclosing and boundary neighbors Boundary neighbors mutually help to discover neighbors boundary neighbor (B.N.)‏L. Blue unknown neighborL. Green normal AOI neighborGreen E.N. & B.N.Pink enclosing neighbor (E.N.)‏Yellow selfWhite Area of Interest (AOI)‏Circle Use Voronoi to solve the neighbor discovery problem