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The QoS requirements of game messages may differ because of the latter’s intrinsic characteristics. In this paper, we propose three content-based strategies for quantifying the effects of different QoS levels. The strategies assign appropriate QoS requirements for game messages based on our analysis of Angel’s Love action logs. We evaluate several transport protocols, including TCP, UDP, SCTP, DCCP, and our content-based transport protocol using the action logs of Angel’s Love. Through simulations, we quantify the performance of our content-based strategies. The results show that the strategies incur much lower end-to-end delay and end-to-end jitter than existing transport protocols.
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M
MNetChih-Ming Chen1, Kuan-Ta Chen2, and Polly Huang1
1National Taiwan University 2Academia SinicaLab
MotivationMotivationMotivation
There is no consensus on protocols for MMORPGs
MMORPGs requirementsLow transmission latencyNo unexpected “lags”
Multi‐streaming• Put different message types into separate streams• e.g., move message, attack message, talk messageOptional ordering• Certain message types do not require in‐order transport• e.g., move message, attack messageOptional reliability• Certain message types do not require reliability• e.g., move message
Quantifying the Effect of ContentQuantifying the Effect of Content‐‐based Transportbased TransportStrategies for Online Role Playing GamesStrategies for Online Role Playing Games
Quantify the effect of content‐based transport strategies
Evaluate existing transport protocols
• TCP, UDP, DCCP, SCTPPropose and evaluate three content‐based transport strategies usingnetwork simulations
ObjectiveObjectiveObjective
http://mmnet.iis.sinica.edu.tw
Multimedia Networking and Systems LabInstitute of Information Science, Academia Sinica
Protocol MMORPGsTCP World of Warcraft, Lineage I/II, Guild Wars, Ragnarok
Online, Anarchy Online, Angel’s LoveUDP EverQuest, City of Heroes, Star Wars Galaxies, Ultima
Online, Final Fantasy XITCP/UDP Dark Age of Camelot
Users’ action trace of Angel’s Love
Real-Life Game TracesRealReal--Life Game TracesLife Game Traces
User ID Actions (M: Move, A: Attack, T: Talk)10159 MMMMMMMMMMMMMAMMAMMMMMMAMMMMMMMMMM12454 MMAAMAMMMMMAAMAMAMAMAMAMAMAMAMAMAMAMA16728 MMMMMMMMMMMMMMMMMMMMMMAMMTTTTTTTTTTTT
Message Type In-Order Delivery ReliabilityMoveAttack √
Talk √ √
Strategy Multi-Streaming Optional Ordering
Optional Reliability
MRO √
MR √ √
M √ √ √
Performance EvaluationPerformance EvaluationPerformance EvaluationAverage end‐to‐end transmission latencies
Average end‐to‐end delay jitters (standard deviation of delays)
Link Bandwidth Propagation DelayServer <--> Router 600 Kbps 70 msRouter <--> Router 600 Kbps 70 msRouter <--> Client 64 ~ 128 Kbps 70 msRouter <--> Traffic Node 64 ~ 128 Kbps 70 ms
SummarySummarySummarySimulation SetupSimulation SetupSimulation Setup
Transport StrategiesTransport StrategiesTransport Strategies
Trace‐driven network simulation using ns‐2 simulatorFishbone topology• 1 game server • 2 network routers• n game clients • m cross traffic pairs
20 40 60 80 100 120 140
180
200
220
240
260
280
300
Client Traffic
Client #
Mea
n de
lay
(ms)
TCPUDPSCTP
P_MROP_MRP_M
20 40 60 80 100 120 140
200
300
400
500
600
Server Traffic
Client #
Mea
n de
lay
(ms)
TCPUDPSCTP
P_MROP_MRP_M
20 40 60 80 100 120 140
050
100
150
200
250
Client Traffic
Client #
Mea
n jit
ter
(ms)
TCPUDPSCTP
P_MROP_MRP_M
20 40 60 80 100 120 140
010
020
030
040
050
060
0
Server Traffic
Client #
Mea
n jit
ter
(ms)
TCPUDPSCTP
P_MROP_MRP_M
Bandwidth & propagation delay
11 pairs cross traffic with 500 Kbps sending rate
P_MRO P_MR P_M
Client Traffic
Protocol
Sco
re
020
4060
8010
0
0 2 0 0
55
75
70 Clients140 Clients
P_MRO P_MR P_M
Server Traffic
Protocol
Sco
re
020
4060
8010
0
28 10
33
45
69
70 Clients140 Clients
P_MRO P_MR P_M
Client Traffic
Protocol
Sco
re
020
4060
8010
0
0 1 1 0
69
79
70 Clients140 Clients
P_MRO P_MR P_M
Server Traffic
Protocol
Sco
re
020
4060
8010
0
15 5
28
46
73
70 Clients140 Clients
Improvement of Delay Improvement of Delay Jitter
Server
CN1
CN2
TN1
CNi
TN2TNj
CNi+1
CNi+2
TNj+1
CNn
TNj+2TNm
. . . . . .
. . . . . .
Client Node (CN)Traffic Node (TN)
Client to Server Server to ClientProtocol Delay Jitter Delay JitterTCP NA NA NA NASCTP ≈ ≈ ★ ★
DCCP (TCP-like) ★★★★ ★★★★ ★★★ ★★★
DCCP (TFRC) ☆ ☆ ☆ ☆
UDP ★★★★ ★★★★ ★★★★ ★★★★
PMRO ≈ ≈ ★ ★
PMR ≈ ≈ ★★ ★★
PM ★★★ ★★★ ★★★ ★★
Description: NA denotes incomparable, ≈ denotes similar, ☆ denotes worse, ★ denotes better, ★★ denotes much better, ★★★ denotes good, ★★★★ denotes very good, and ★★★★ denotes excellent.
