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Modeling peer-peer file sharing systems
Ge, Z.; Figueiredo, D.R.; Sharad Jaiswal; Kurose, J.; Towsley, D.;
INFOCOM 2003. Twenty-Second Annual Joint Conference of the IEEE Computer and Communications Societies.
Presentation by Tony Sung, MC Lab, IE CUHK23th September 2004
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Outline
Significance of the Paper
Modeling P2P Systems
Capturing the Parameters
The Results
Conclusion
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Significance of the Paper
Mathematical Model that addresses
Scalability
Impact of freeloaders
Impact of imbalanced service capacity and file request load
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Significance of the Paper
Results
Limited-scope flooding worsen performance
Freeloaders do not have significant impact
Centralized indexing approach can scale gracefully up to its capacity
Degradation due to replication-popularity mismatch is minor
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Modeling P2P Systems
Modeling
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Modeling P2P Systems
3 types of systems
CIA – Centralized Indexing Architecture
DIFA – Distributed Indexing with Flooding Architecture
DIHA – Distributed Indexing with Hashing Architecture
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Modeling P2P Systems
A multiple class closed queuing network
C classes of peers: N = (N (1),…, N (C)) M number of distinct files sorted according to
availability
States Thinking, Querying,
Downloading, Offline
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Modeling P2P Systems
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Capturing the Parameters
Capturing Parameters
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Capturing the Parameters
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A single class case, C = 1, Na = (Na(1))
(Popularity, Zipf, assumed …)
(File service rate)
? (Common services’ service rate)
? (Query Failure Rate)
Capturing the Parameters
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Common services’ service rate
CIA:
DIFA:
DIHA:
Capturing the Parameters
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Query failure rate
CIA:
DIFA:
DIHA:
Capturing the Parameters
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Freeloaders: 2 classes
Capturing the Parameters
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Solving the model
Visiting Ratio
Service Demand
Bottleneck Queue
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Results
Results
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Results
Scalability
CIA
DIFA
DIHADIHA
CIA
DIFA
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Results
Freeloader’s impact onsystem throughput
Non-freeloaderpopulation
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Results
Freeloader’s impact onnon-freeloader throughput
Non-freeloaderpopulation
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Results
Reason of DIFA’s poor performance
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Results
Mismatch in file popularity and replication
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Results
Mismatch in file popularity and replication
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Conclusion
Simple, representative math. Model
Flexible across architectures
Dealt with different classes of peers
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Results
Freeloader’s impact on system throughput- another perspective
