Network Analysis of Counter-strike and Starcraft Mark Claypool, David LaPoint, Josh Winslow Worcester Polytechnic Institute Worcester, MA, USA

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

What is Counter-strike?

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

Why Study Counter-strike? (2 of 2)

What is Starcraft?

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

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

Experimental Setup 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 Internet Game Client Hub Game Server Sniffer Campus

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

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

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

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

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

Packet Sizes

CS Packet Sizes by Server

Packet Interarrival Times

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

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

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:

Network Analysis of Counter-strike and Starcraft Mark Claypool, David LaPoint, Josh Winslow Worcester Polytechnic Institute Worcester, MA, USA