Network Analysis of Counter-strike and Starcraft

1. Network Analysis of Counter-strike and Starcraft Mark Claypool, David LaPoint, Josh Winslow Worcester Polytechnic Institute Worcester, MA, USA http://www.cs.wpi.edu/~claypool/

2. Why Study Games? • Rapidly growing in popularity [9] • 18 million on-line gamers, 1.6 billion dollar industry • Growing fraction of network traffic • Game consoles (Xbox, PS2, GameCube) online • Previous studies measured Web or Multimedia traffic • Games are different  low latency, small packets, bursty traffic • Possible benefits • Design networks to better accommodate network game traffic “turbulence” • Provide data for more realistic network simulations  Network analysis of Counter-strike and Starcraft

3. What is Counter-strike?

4. What is Counter-strike?

5. Why Study Counter-strike? (1 of 2) • Gaming traffic dominated by first-person shooter (FPS) genre [9] (Feng et al, IMW 2002)

6. Why Study Counter-strike? (2 of 2)

7. What is Starcraft?

8. Why Study Starcraft? • Real-Time Strategy (RTS) popular genre alternative to FPS • Starcraft • Best-selling game in 1998 • Dozens of awards • Entrenched user base, especially in Korea • About 15% of Battle.net games are Starcraft

9. Outline • Introduction (done) • Experimental Setup next • Analysis • Game Architectures • Bandwidth Use • Packet Sizes and Arrival • Conclusions

10. Experimental Setup Game Client Internet • Game client (and server) • PIII 800 MHz • nVidea geForce 2 3d w/64 Mbytes memory • 512 Mbytes RAM • 10 Mbps NIC • Sniffer PC ran Commview • Runs: Starcraft 2-8 players, Counter-strike 3-10 players Sniffer Hub Campus Game Server

11. Game Architectures • Counter-strike (CS) • Client-server • Clients send data only to server • Server maintains game state • Server sends all user actions to every other user • Starcraft (SC) • Peer-to-peer • Clients periodically send user actions to every other user

12. SC Bandwidth Sent and Game Size Averages: 650 bytes/s Stddev: 30% +1500/12% per pair Even bandwidth per user

13. CS Bandwidth Sent by Client Average: 2690 bytes/s Stddev: 110% Bandwidth differs per client (Map change)

14. CS Bandwidth Sent by Server Average: 6470 bytes/s Stddev: 135% (Map change)

15. Bandwidth Analysis Summary • Starcraft more consistent than Counter-strike • Starcraft clients sends similar • Counter-strike clients sends vary • Largest games still possible over a modem • Starcraft can have up to 8 • Counter-strike can have up to 32 • Counter-strike server may have network bottleneck

16. Packet Sizes

17. CS Packet Sizes by Server

18. Packet Interarrival Times

19. Packet Analysis Summary • Counter-strike and Starcraft have significantly smaller packets than typical (400 bytes [9]) • Counter-strike sends bursts of small packets, while Starcraft steadier • Number of players does not affect packet sizes for Starcraft or Counter-strike clients • Server packet sizes and rates very considerably depending upon the action and number of players

20. Conclusions • Network games different than typical Internet applications • Very interactive • Small, bursts of UDP packets • Starcraft (RTS) • Steadier data rate scales linearly with users • Small packet sizes • Counter-strike (FPS) • Burstier data rate depending upon action • Packet sizes for server depend upon action

21. Future Work • Incorporate into simulator for network impact studies (NS-2) • Simulate “rounds” in Counter-strike • Other RTS and FPS games • Warcraft III (RTS) • America’s Army (FPS) • Other genres and games • The Sims Online • Data traces available at: http://perform.wpi.edu/downloads/

22. Network Analysis of Counter-strike and Starcraft Mark Claypool, David LaPoint, Josh Winslow Worcester Polytechnic Institute Worcester, MA, USA http://www.cs.wpi.edu/~claypool/