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Peer-to-Peer Networking and Networked Virtual Environments

Peer-to-Peer Networking and Networked Virtual Environments. By Jehn-Ruey Jiang CSIE Department National Central University. P2P Networking. GET /index.html HTTP/1.0. HTTP/1.1 200 OK. Client/Server Architecture. Server. Clients. The Client Side.

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Peer-to-Peer Networking and Networked Virtual Environments

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  1. Peer-to-Peer Networking andNetworked Virtual Environments By Jehn-Ruey Jiang CSIE Department National Central University

  2. P2P Networking

  3. GET /index.html HTTP/1.0 HTTP/1.1 200 OK ... Client/Server Architecture Server Clients

  4. The Client Side • Today’s clients can perform more roles than just forwarding users requests • Today’s clients have: • more computing power • more storage space • Thin client  Fat client

  5. Evolution at the Client Side IBM 8-bit PC @ 4.77MHz 360k diskettes 64-bit PC @ 4-core 4GHz750GB HD DEC’S VT100 No storage 2011 ‘70 ‘80

  6. What Else Has Changed? • The number of home PCs is increasing rapidly • Most of the PCs are “fat clients” • As the Internet usage grow, more and more PCs are connecting to the global net • Most of the time PCs are idle • How can we use all this? Peer-to-Peer (P2P)

  7. Peer-to-Peer Architecture Gateway Server Peers

  8. The architectures • Server-based architecture • Client-Server / Server-Cluster • Problems： • Limited resources • All loads are centered on the server • Server-based architecture has low scalability. • The setup and maintenance cost is high. • Peer-to-Peer (P2P) architecture • Advantages： • Distributing loads to all users • Users consume and provide resources • P2P architecture has high scalability. • The setup and maintenance cost is low.

  9. What is peer-to-peer (P2P)? • “Peer-to-peer is a way of structuring distributed applications such that the individual nodes have symmetric roles. Rather than being divided into clients and servers each with quite distinct roles, in P2P applications a node may act as both a client and a server.”-- Charter of Peer-to-peer Research Group, IETF/IRTF, June 24, 2004(http://www.irtf.org/charters/p2prg.html)

  10. Resources Sharing • What can we share? • Computer-related resources • Shareable related-computer resources: • CPU cycles- seti@home, GIMPS • Bandwidth- PPLive, PPStream • Storage Space- OceanStore, Murex • Data - Napster, Gnutella • People - Buddy Finder • Camera, Microphone, Sensor, Service???

  11. NVEs

  12. Massively Multiplayer Online Games • MMOGs are growing quickly • Multi-billion dollar industry • 10 million subscribers for World of Warcraft • 600,000 concurrent users

  13. Adaptive Computing and Networking Lab, CSIE, NCU

  14. Adaptive Computing and Networking Lab, CSIE, NCU

  15. NCU ACNLab

  16. NASAWorld Wind

  17. Google Earth

  18. Zoom in…

  19. NCU ACNLab To HsinChu..

  20. and NTHU..

  21. It is going to be 3D

  22. NTHU3DStudent Center…

  23. To the ground

  24. NCU ACNLab 3-Dimensional Virtual Tourism Google Earth Virtual Earth 3D (MicroSoft) NASA World Wind X3D Earth

  25. MicroSoft Virtual Earth 3D

  26. Google Earth

  27. DARPA SIMNET: screenshot From Bruce Sterling's "War is Virtual Hell,“ (1993).

  28. CALVIN: a distributed collaborative virtual environments for architectural layout designs (1996)

  29. NVE • Anetworked virtual environment (NVE) is a computer-generated virtual world where multiple geographically dispersed users can assume virtual representatives (or avatars) to concurrently interact with each other in real time through networked devices. • Also called adistributed virtual environment (DVE) orcollaborative virtual environment (CVE)

  30. NVE • Examples of NVEs include • early DARPA SIMNET and DIS systems • early distributed collaborative virtual environments • currently booming Massively Multiplayer Online Games (MMOGs) • future multi-user3DVTs • future multi-user Web 3D browser

  31. Question • Most VNEs, especially MMOGs, are server-based and thus suffer from the scalability problem. • Can we apply the P2P concept to VNEs? YES!

  32. P2P and NVEs

  33. Questions • How can we manage states of avatars, NPCs and objects of an NVE? • Answer: • Fully connected point-to-point • Client/Server (C/S) • Client/Server-cluster • Peer-to-peer

  34. A simple solution (point-to-point)‏ But…too many irrelevant messages N * (N-1) connections ≈ O(N2) Not scalable! Source: [Funkhouser95]

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

  36. Current solution(server-cluster)‏ Still limited by servers. Expensive to deploy & maintain. Source: [Funkhouser95]

  37. The Problem • Client-server: resources limited by provisioning Resource limit [Funkhouser95]

  38. The Solution • Peer-to-Peer: resources grow with demand Resource limit [Keller & Simon 2003]

  39. P2P Overlay for NVEs (1):DHT-based: SimMUD [Knutsson et al. 2004] (UPenn) • Pastry (DHT mapping) + Scribe (Multicast) • Fixed-Sized Regions • Coordinators

  40. P2P Overlay for NVEs (1):DHT-based: SimMUD MMOG GAME SCRIBE (Multicat support) PASTRY (P2P overlay)

  41. P2P Overlay for NVEs (1):DHT-based: SimMUD

  42. P2P Overlay for NVEs (2):Neighbor-list Exchange [Kawahara et al. 2004] (Univ. of Tokyo) • Fully-distributed • Nearest-neighbors • List exchange • High transmission • Overlay partition

  43. P2P Overlay for NVEs (3): Mutual Notification: Solipsis [Keller & Simon 2003] (France Telecomm R&D) • Links with AOI neighbor • Mutual cooperation • Inside convex hull • Potentially slow discovery • Inconsistent topology

  44. P2P Overlay for NVEs (4)Voronoi-based Overlay Network : VON • Use Voronoi diagram to solve the neighbor discovery problem • Each node constructs a Voronoi diagram of its neighbors • Identify enclosing and boundary neighbors • Mutual collaboration in neighbor discovery

  45. Model for NVEs • Many nodes on a 2D plane • An avatar needs to know only those within Area of Interest (AOI)‏ Area of Interest(AOI) ★: self ▲: neighbors

  46. Voronoi Diagram • 2D Plane partitioned into regions by nodes, each region contains all the points closest to its node region node

  47. Voronoi-based Overlay Network : VON ● node i and the big circle is its AOI ■ enclosing neighbors ▲ boundary neighbors ★ both enclosing and boundary neighbors ▼ normal AOI neighbors ◆ irrelevant nodes

  48. Procedure (MOVE) 1) Positions sent to all neighbors, mark messages to B.N. B.N. checks for overlaps between mover’s AOI and its E.N. 2) Connect to new nodes upon notification by B.N. Boundary neighbors New neighbors

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