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

Mark Claypool

Computer Science DepartmentWorcester Polytechnic Institute

http://www.cs.wpi.edu/~claypool/papers/hand-held/

* The term “footprint" is often used in systems work in the context of the basic size a piece of memory of some software. In a network, the size and distribution of packets over time is important, hence the word “turbulence”

October 2005ACM NetGames, Hawthorne, NY 2

Motivation (1 of 2)

• Computer game sales in U.S. on par with Hollywood box office [ESA – 2005, National Organization of Theatre Owners – 2005]

• For frequent game players, 43% play online [ESA - 2004]

• Through 2004, hand-helds primarily single-player

• Spring 2005, Sony PSP and Nintendo DS released and support multiple players– Using IEEE 802.11 (WLAN)

• Significant, since WLAN increasingly deployed– Dartmouth, Logan Airport, Philadelphia, my

house…

October 2005ACM NetGames, Hawthorne, NY 3

Motivation (2 of 2)

•Poor WLAN connections degrade all [Heusse et al. 2003, Bai and Williamson 2004, Gretarsson 2005]

– Equal access means poor connection becomes bottleneck

•There have been numerous studies of popular PC games [Borella 2000, Feng et al. 2002,

Faerber 2002, Lang et al. 2004] and consoles [Lang et al 2005]

•To the best of our knowledge, none on new hand-helds

October 2005ACM NetGames, Hawthorne, NY 4

Questions

• Turbulence for hand-held network games? – Characterizing frame sizes and inter frame times 1st

step for building models

• Turbulence differs across hand-helds (PSP vs. DS)?– If not, then can concentrate on one hand-held

• Turbulence differs across games (Metroid vs. Mario)?– If not, then can concentrate on one game

• Turbulence differs from PC games?– If not, then can re-use mature models for PC games

• Hand-helds interfere with other wireless traffic?– If yes, then plan accordingly

October 2005ACM NetGames, Hawthorne, NY 5

Outline

•Introduction (done)

•Background (next)

•Experiments

•Results

•Conclusions

October 2005ACM NetGames, Hawthorne, NY 6

Nintendo DS

• System – Resolution 256x192,

260k colors– 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, only

• Ad hoc mode– No IP stack (UDP/TCP)

October 2005ACM NetGames, Hawthorne, NY 7

Sony PSP

• System– Resolution 480x272

pixels, 24-bit color– 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

October 2005ACM NetGames, Hawthorne, NY 8

Outline

•Introduction (done)

•Background (done)

•Experiments (next)

•Results

•Conclusions

Metroid Prime Hunters

Ridge Racer Super Mario Picto Chat

Need for Speed

World Tour Soccer

Untold Legends

Hotshots Golf

Nin

tend

o D

SS

on

y P

SP

Games Selected

October 2005ACM NetGames, Hawthorne, NY 10

Experimental Setup

• First floor of wooden house

• Sniffing via Ethereal (v0.10.3) on laptop

• Three APs visible, but no traffic except beacons

• Games on WLAN channels 1, 6, 11

• For each game– Single player to gain familiarity,

then two-player– Three runs, gather all data

• For two games– Three wireless locations: Bad,

Good, Excellent

• For one game– Bulk download on PC

Dell Inspiron 8600Netgear WG511 802.11b/g with Intersil's PRISM GT chipset

October 2005ACM NetGames, Hawthorne, NY 11

Outline

•Introduction (done)

•Background (done)

•Experiments (done)

•Results (next)

•Conclusions

October 2005ACM NetGames, Hawthorne, NY 12

Game Phases

October 2005ACM NetGames, Hawthorne, NY 13

Nintendo DS vs. Sony PSP

October 2005ACM NetGames, Hawthorne, NY 14

Frame Sizes

Nintendo DS Sony PSP

October 2005ACM NetGames, Hawthorne, NY 15

Inter Frame Times

Nintendo DSSony PSP

Why are there so few frames at 0 for some PSP games?

October 2005ACM NetGames, Hawthorne, NY 16

Percentage of Broadcast Frames

Doom all over again?

October 2005ACM NetGames, Hawthorne, NY 17

Wireless Connection Quality

October 2005ACM NetGames, Hawthorne, NY 18

Impact on Contending TCP Throughput

October 2005ACM NetGames, Hawthorne, NY 19

Conclusions

• Hand-held games frequent sends of small data– Payloads less than 100 bytes– Inter frame times (non-ACKS) less than 20 msec– Like PC and console games, but more frequent

• Nintendo DS games similar to each other, while Sony PSP games vary considerably

• Nintendo DS games different than Sony PSP games– DS games have smaller frames – Some PSP send mostly broadcast

• Some game phases may adversely affect throughput for contending applications

October 2005ACM NetGames, Hawthorne, NY 20

Future Work

•Multiple-players– Tested 2, games support 2-8, systems 2-

16

•Turbulence during other game phases– Synchronization phase? – Size and duration of phases?

•Interaction with other traffic– Same channel, overlapping channel

•Infrastructure mode– Wide-Area network (loss, latency …)

October 2005ACM NetGames, Hawthorne, NY 21

Acknowledgements

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

Mark Claypool

Computer Science DepartmentWorcester Polytechnic Institute

http://www.cs.wpi.edu/~claypool/papers/hand-held/