On the 802.11 Turbulence of Nintendo DS and Sony PSP Hand-held Network Games

1. On the 802.11 Turbulence of Nintendo DS and Sony PSP Hand-held Network Games Research Seminar Course Polyxeni Kleniati Department of Computing Imperial College London Monday, 27 February 2006

2. About the Author • Mark Claypool • Associate Professor, CS Department, Worcester Polytechnic Institute • Director, WPI’ s Interactive Media and Game Developmentundergraduate degree Research Seminar Course

3. About the Author • Research Methodology • Observe, Hypothesize, Design, Experiment, Analyze, Report • "The fundamental principle of science, the definition almost, is this: the sole test of the validity of any idea is experiment." -- Richard P. Feynman • Research Interests • Distributed Systems, Multimedia, Performance Analysis, Collaborative Filtering, Perceptual Quality, Wireless Network and Network Games • Publications • Journals (9), Conferences (51), Books (2), Demos, Posters, Technical Reports and so on • January 2006, his paper “The Effects of Frame Rate and Resolution on Users Playing First Person Shooter Games”, presented in Proceedings of ACM/SPIE Multimedia Computing and Networking (MMCN), won the best paper award Research Seminar Course

4. About the Presenter • Polyxeni – Margarita Kleniati • 1st year PhD student • Supervisor: Professor Berç Rustem • Group: High Performance Computing (HPC) • Research Area: Computational Management Science (CMS) • The research of our group is focused on decision making under uncertainty, with applications to finance, scheduling, worst-case analysis and chemical engineering • My Topic: Semidefinite Programming and Global Optimization of Polynomials Using Higher Order Moments Research Seminar Course

5. About the Paper • Presented in Proceedings of the 4th ACM SIGCOM workshop on Network and System Support For Games • Session: Game Traffic Characterization • Year of Publication: 2005 • Publisher: ACM Press, New York, USA • Best Paper award! Research Seminar Course

6. Outline • Introduction • Motivation & Objective of the paper • B.I. on IEEE 802.11, Nintendo DS & Sony PSP • Methodology • Games Selected • Wireless Framework, Gameplay & Sniffing • Experimental Setup • Results • Game Phases Research Seminar Course

7. Outline • Results • Turbulence • Nintendo DS vs. Sony PSP (bitrates) • Frame Sizes (CDFs) • Inter Frame Times (CDFs) • Wireless Connection Quality • Impact on TCP throughput • Conclusions • Discussion Research Seminar Course

8. Motivation • Recently, the computer game industry has seen a substantial growth • Computer game sales in US comparable with Hollywood box office • Increase in residential broadband Internet connections with high capacities • Hand-held gaming consoles were primarily single-player until 2004 • Spring 2005, Sony PSP and Nintendo DS released and support multi-player gameplay, using IEEE 802.11 (WLAN) Research Seminar Course

9. Motivation • This is significant for many reasons: • More & more home users access the internet via a WLAN • Growth in WLAN increases the likelihood that concurrent hosts compete on the same channels • The traffic generated by one host on a WLAN can degrade the performance of other hosts on the WLAN • Essential to know the network load caused by hand-held game traffic • Little research has been done on hand-helds using 802.11 protocol Research Seminar Course

10. Objective • This paper examines the network characteristicsfor a variety of network games on the Nintendo DS and the Sony PSP • The author uses the terminology turbulence to denote the network characteristics: • size and frequency of data sent • overall bitrate Research Seminar Course

11. Objective – Questions • What is the network turbulence for hand-held network games? • Does the network turbulence differ between PSP and DS? • Does the network turbulence differ among different games on the same hand-held? • Does the network turbulence for hand-held games differ from PC games? • Does hand-held game traffic affect the Internet traffic on the same wireless channel? Research Seminar Course

12. IEEE 802.11 • IEEE 802.11* denotes a set of Wireless LAN/WLAN standards developed by working group 11 of the IEEE LAN/MAN Standards Committee (IEEE 802) • The term IEEE 802.11 is also used to refer to the original 802.11, which is also called 802.11 legacy • The 802.11 family currently includes six modulation techniques that all use the same protocol • The most popular techniques are those defined by the b, a and g amendments to the original standard *The information is taken from Wikipedia, the free on-line encyclopedia. Research Seminar Course

13. IEEE 802.11 – Protocols • 802.11 legacy: The original version of the standard IEEE 802.11 released in 1997 specifies two raw data rates of 1 Mbits/s and 2 Mbits/s to be transmitted in the Industrial Scientific Medical frequency band at 2.4 GHz • The original standard also defines Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) as the media access method • Legacy 802.11 was rapidly supplemented by 802.11b. Widespread adoption of 802.11 networks only occurred after 802.11b was approved and as a result few networks run on the 802.11 standard Research Seminar Course

14. IEEE 802.11 – Protocols • 802.11b: The 802.11b amendment to the original standard was approved in 1999. 802.11b has a maximum raw data rate of 11 Mbits/s and uses the same CSMA/CA media access method defined in the original standard. Due to the CSMA/CA protocol overhead, in practice the maximum 802.11b throughput that an application can achieve is about 5.9 Mbit/s over TCP and 7.1 Mbit/s over UDP • 802.11b is usually used in a point-to-multipoint configuration, wherein an access point communicates via an omni-directional antenna with one or more clients that are located in a coverage area around the access point • 802.11b cards can operate at 11 Mbit/s but will scale back to 5.5, then 2, then 1 Mbit/s (Adaptive Rate Selection), if signal quality becomes an issue. Since the lower data rates use less complex methods of enconding the data, they are less susceptible to corruption due to interference and signal degradation Research Seminar Course

15. Nintendo DS • System • Resolution 256×192 pixels, 260k colours • Dual ARM processors • ARM 9 at 67 MHz • ARM 7 at 33 MHz • 4 Mbytes RAM • Touch-pad • Network • WLAN is IEEE 802.11b • Short preamble • Wireless capacities of 1 Mbps or 2 Mbps • Ad hoc mode • No IP stack (UDP/TCP) Research Seminar Course

16. Sony PSP • System • Resolution 480×272 pixels, 24-bit colour • Dual MIPS R4000 processors at 333 MHz • 32 Mbytes RAM • Analog joystick • Network • WLAN is IEEE 802.11b • 1, 2, 5.5, 11 Mbps • Ad hoc mode and infrastructure mode • IP stack Research Seminar Course

17. Games Selected Research Seminar Course

18. Wireless Framework • First floor of wooden house • Used 2 Sony PSP and 2 Nintendo DS close to each other (10 feet), except when deliberately taken further apart • Sniffing via Ethereal (v0.10.3) on laptop • 3 APs were visible by the sniffer, but no additional traffic apart from the beacons • Games on WLAN channels 1, 6, 11 Research Seminar Course

19. Gameplay & Sniffing • Sniffer able to capture the entire frame (MAC headers, extra physical/MAC layer information) • Each game was played first in single player mode • Then, two-player version of each game • 3 runs, gather all data • For two games, 3 wireless locations (Bad, Good, Excellent) • For one game, bulk download on PC Research Seminar Course

20. Experimental Setup Dell Inspiron 8600 Netgear WG511 802.11 b/g with Intersil‘ s PRISM GT chipset Research Seminar Course

21. Game Phases • Setup • Minimal network traffic • Synchronization • High bitrates • Play • Moderate bitrates • Transition • Low bitrates Research Seminar Course

22. Game Phases Research Seminar Course

23. Nintendo DS vs. Sony PSP Research Seminar Course

24. Nintendo DS vs. Sony PSP Research Seminar Course

25. Frame Sizes – Cumulative Distribution Functions Sony PSP Nintendo DS Research Seminar Course

26. Inter Frame Times – Cumulative Distribution Functions Sony PSP Nintendo DS Research Seminar Course

27. Wireless Connection Quality Research Seminar Course

28. Impact on TCP throughput Research Seminar Course

29. Conclusions • What is the network turbulence for hand-held network games? • Frequent sends of small frames of data • Typical hand-held frame sizes are less than 100 bytes • Typical inter frame times are less than 20 msecs (excluding ACKs) • Does the network turbulence differ between PSP and DS? • DS games send smaller frames that the PSP games • Some PSP games send mostly broadcast traffic, while all DS games studied use direct addressing Research Seminar Course

30. Conclusions • Does the network turbulence differ among different games on the same hand-held? • Games on the Nintendo DS have network turbulence similar to each other • Games on the Sony PSP vary considerably in bitrate, frame size, frame frequency, and fraction of broadcast traffic • Does the network turbulence for hand-held games differ from PC games? • Data frames sent by hand-helds are comparable in size to those of PC or console games • Hand-helds send data more frequently, resulting in bitrates that are higher overall than typical PC or console games Research Seminar Course

31. Conclusions • Does hand-held game traffic affect the Internet traffic on the same wireless channel? • Some game phases may have adverse affects on throughput for Internet applications sharing the same 802.11 wireless channel Research Seminar Course

32. Additional Conclusions • Some Sony PSP games primarily use 802.11 broadcast as a means of communicating between the hand-helds • Implications on other wireless devices that share the same channel • Under poor connection quality, the Nintendo DS game studied sends data at higher bitrates • Sony PSP game studied increases bitrates slightly and has difficulty staying connected Research Seminar Course

33. Discussion • Is research on games legitimate? (In my opinion, it is!) • The ultimate goal is to improve games, or to improve protocols, so improving games? • What is the real meaning/importance of the influence of games on internet traffic? • Is there any room for doubt about protocol 802.11b being really supported in both games? Research Seminar Course

34. The End.Any Questions? Thank you.