the effects of loss and latency on user performance in unreal tournament 2003 tom beigbeder, rory...

The Effects of Loss and Latency on User Performance in Unreal Tournament 2003

Tom Beigbeder, Rory Coughlan, Corey Lusher, John Plunkett,

Emmanuel Agu, Mark Claypool

Computer Science DepartmentWorcester Polytechnic Institute

Worcester, MA, USA

http://www.cs.wpi.edu/~claypool/papers/ut2003/

Aug 2004NetGames'04, Portland, OG, USA2

Why Study Network Games and First Person Shooters?

•In 2003, despite economic downturn, games only industry to grow [ESA - 2004]

•43% of frequent game players play online [“Essential Facts”, ESA, 2004]

•First-Person Shooters a top selling genre– 11.5% [“Essential Facts”, ESA, 2003]


The Network and Network Games

• Can be a demanding application in terms of network requirements– Capacity? (Not usually)– Latency? (Sometimes … but when?)– Loss? (Unknown)

• But what about loss?– Retransmission adds to latency

• Knowing QoS constraints useful for– Building better network games– Building better networks to support games (QoS)


Outline

•Introduction

•Experiments

•Analysis

•Conclusions


Methodology

•Characterize FPS user interaction components

•Design maps that exercise each type of interaction

•Construct test environment for measuring the effects of latency and loss

•Conduct user studies

•Analyze the results (see Section 4).


FPS User Interaction Components

•Movement– Simple (Moving in a straight line)– Complex (Running, jumping, turning…)

•Shooting

• Movement and Shooting


Controlling Loss and Latency

•UT2003 Client-Server

•NIST Net router controls network characteristics to each client– Control loss [0%,6%]– Control and latency [0 ms, 400 ms]


Outline

•Introduction

•Experiments

•Analysis– Application Level – Network Level– User Level

•Conclusions


Complex Movement

•Movement not affected by loss or latency•Short-circuit relay


Precision Shooting

•Precision shooting not affected by loss•Precision shooting is affected by latency

•75 ms may make a difference!


Restricted Deathmatch

•Movement and shooting not affected by loss•Movement and shooting affected by latency

•Less clearly so than shooting alone


Full Deathmatch

•Movement and shooting not affected by loss•Movement and shooting barely affected by latency


Outline

•Introduction

•Experiments

•Analysis– Application Level – Network Level – User Level

•Conclusions


Network Turbulence

•No visible effects of loss or latency•Holds for packet sizes, intra packet times


Outline

•Introduction

•Experiments

•Analysis– Application Level – Network Level – User Level

•Conclusions


User-Level Analysis

•75 ms latency, users noticed sluggishness– True even for unrestricted tests

•100 ms was noticeable, less enjoyable– Could be frustrating for precise shooting

•0-3% loss rarely even noticed

•3%+ loss sometimes noticed, but only because gun effects not always displayed


Conclusion

•FPS games not affected by typical Internet loss– Keep loss under 3%– May not bode well for TCP fairness at

higher bitrates

•Can be affected by latency– Keep latencies under 150 ms

•At the network level:– Small packets with low bitrate– Turbulence consistent over all network

conditions


Future Work

•Effects of variance in latency (jitter)

•User adaptation strategy

•Other?

The Effects of Loss and Latency on User Performance in Unreal Tournament 2003

Tom Beigbeder, Rory Coughlan, Corey Lusher, John Plunkett,

Emmanuel Agu, Mark Claypool

Computer Science DepartmentWorcester Polytechnic Institute

Worcester, MA, USA

http://www.cs.wpi.edu/~claypool/papers/ut2003/

the effects of loss and latency on user performance in unreal tournament 2003 tom beigbeder, rory...

Documents

latency slide

ms slide

loss movement

shooting movement

ms latency

relay slide

loss precision shooting

games qos slide