User selfishness vs file availability in P2P file

Authors: Masahiro Sasabe Naoki Wakamiya Masayuki Murata

Publish Date: 2009/04/16

Volume: 3, Issue: 1, Pages: 17-26

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Abstract

In a PeertoPeer P2P filesharing system a node finds and retrieves its desired file If multiple nodes cache the same file to provide others we can achieve a dependable filesharing system with low latency and high file availability However a node has to spend costs eg processing load or storage capacity on caching a file Consequently a node may selfishly behave and hesitate to cache a file In such a case unpopular files are likely to disappear from the system In this paper we aim to reveal whether effective caching in the whole system emerges from autonomous and selfish node behavior We discuss relationship between selfish node behavior and system dynamics by using evolutionary game theory Through theoretic analysis we show that a filesharing system can be robust to file disappearance depending on a cost and demand model for caching even if nodes behave selfishly Furthermore we also conduct several simulationbased analysis in terms of network structures evolving network load balancing and system stability As a result we demonstrate that a filesharing system with good properties ie robustness to file disappearance low search latency well loadbalancing and high stability can be achieved independent of network structures and dynamicsThis research was supported in part by a GrandinAid for Scientific Research A 1820004 a GrantinAid for Young Scientists B 20700061 and “Global COE Centers of Excellence Program” of the Ministry of Education Culture Sports Science and Technology in Japan This research is an extended version of the paper presented at IEEE Symposium on Computers and Communications ISCC’07 1

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