June 11, 2007 Telia-Sonera (TSIC) Distributed games Prof. Henning Schulzrinne Dept. of Computer Science Columbia University (with material by M. Claypool et al.)

June 11, 2007 Telia-Sonera (TSIC) Game types LabelDescriptionExamples FPSFirst-person shooterDoom, Quake, Unreal Tournament, Half Life, Halo RTSReal-time strategy (“ harvest, build, destroy”) WarCraft III, StarCraft, Age of Mythology RPGRole-playing game (no winners & losers) OpenRPG Racingfirst or third-person avatarNeed for Speed Sportsthird-person avatarMadden Football, Golf MMOMassive multiplayer online (persistent universe) World of WarCraft, EverQuest

June 11, 2007 Telia-Sonera (TSIC) Why Does Latency Matter? Time User Input Render Input Process and Validate Input Message: User Input Message: Ok User Input Response time Affects responsiveness G. Armitage & M. Claypool, June 2006

June 11, 2007 Telia-Sonera (TSIC) How Much Does Latency Matter? Depends upon precision of task M. Claypool & K. Claypool, Nov. 2006

June 11, 2007 Telia-Sonera (TSIC) How Much Does Latency Matter? Depends upon deadline of task M. Claypool & K. Claypool, Nov. 2006

June 11, 2007 Telia-Sonera (TSIC) OmnipresentThird-Person Avatar First-Person Avatar Precision and Deadline Deadline Shooting Sniper Racing Casting Area Spell Shooting Machine Gun Shooting Grenades Exploring Drinking Health Potion Moving Building Fighting Combat Running Precision TighterLooser Higher Lower M. Claypool & K. Claypool, Nov. 2006

June 11, 2007 Telia-Sonera (TSIC) Traffic summary Applicationbandwidth (w/headers)packet sizeinterarrival VoIP kb/s B20-50 ms Quake 3SC: 16 kb/s (~players) CS: 10 kb/s SC: B CS: 60 B 50 ms 12 ms Half LifeSC: ~26 kb/s CS: 13 kb/s SC: B CS: B 60 ms 33, 50 ms Nintendo DS and Sony PSP (802.11) kb/s ( kb/s) B15-60 ms XBox Halo 2150 kb/s (11 players) SC: B CS: 100 B CS: 40 ms FPS use UDP, MMO TCP. Older generations of RTS used UDP, new ones TCP.

June 11, 2007 Telia-Sonera (TSIC) Player Performance vs. Latency M. Claypool & K. Claypool, Nov VoIP

June 11, 2007 Telia-Sonera (TSIC) Conclusions Increasing variety of networked games in all categories Both local (e.g., ) and wide-area Wide-area mostly server-based to maintain persistent universe Traffic very similar to VoIP –regular updates every ms –often, UDP with modest-sized packets (hundreds of bytes) Latency requirements more stringent than VoIP for FPS –similar or more lenient for other game types Increasing use of voice as human-human side channel

June 11, 2007 Telia-Sonera (TSIC) References Mark Claypool and Kajal Claypool, “Latency and Player Actions in Online Games”, Communications of the ACM, 49(11), Nov Chris Chambers, Wu-chang Feng, Sambit Sahu and Debanjan Saha, “Measurement-based Characterization of a Collection of On-line Games", Proceedings of the ACM Internet Measurement Conference (IMC), Berkeley, CA, USA, Oct Mark Claypool, “On the Turbulence of Nintendo DS and Sony PSP Hand-held Network Games”, In Proceedings of the 4th ACM Network and System Support for Games (NetGames), Hawthorne, NY, USA, Oct Mark Claypool, “The Effect of Latency on User Performance in Real-Time Strategy Games”, Elsevier Computer Networks, special issue on Networking Issues in Entertainment Computing, 49(1), pp , Sept Sebastian Zander and Grenville Armitage, “A Traffic Model for the Xbox Game Halo 2", Proceedings of International Workshop on Network and Operating System Support for Digital Audio and Video (NOSSDAV) Stevenson, WA, USA, June Tanja Lang, Philiip Branch and Grenville Armitage, “A Synthetic Traffic Model for Quake 3", ACM SIGCHI Advances in Computer Entertainment (ACE), Singapore, June Tanja Lang, Grenville Armitage, Philip Branch and Hwan-Yi Choo, “A Synthetic Traffic Model for Half Life", Australian Telecommunications Networks & Applications Conference (ATNAC), Melbourne, Australia, Dec

June 11, 2007 Telia-Sonera (TSIC) References, cont’d. James Nichols and Mark Claypool. “The Effects of Latency on Online Madden NFL Football”, In Proceedings of the 14th ACM International Workshop on Network and Operating Systems Support for Digital Audio and Video (NOSSDAV), Kinsale, County Cork, Ireland, June 16-18, Online at: Grenville Armitage, Mark Claypool, and Philip Branch. “Networking and Online Games: Understanding and Engineering Multiplayer Internet Games”, John Wiley and Sons, Ltd., June ISBN Online at: