Improving fairness in peer-to-peer networks by separating the role of seeders in network infrastructures

Abstract

:Fairness is one of the most important challenges that should be considered as a priority when designing a P2P file-sharing network. An unfair P2P network may attract free-riders, frustrate the majority of users, and consequently shorten the longevity of files. When BitTorrent protocol was first introduced, by suggesting new algorithms like tit-fortat or rarest-first and combining them with methods like choking and unchoking, it pushed fairness one step forward. However, BitTorrent did not bring a plenary solution and has its own shortcomings. For instance, neither this protocol nor other P2P protocols that we are aware of precisely indicate how seeders should be treated in their networks. Most of the time they dictate that seeders upload as much as possible. With this approach, seeders can easily be abused by free-riders. It gets even worse when we realize that for lack of a good infrastructure a lawful user may become a free-rider unknowingly. The purpose of this paper is to address this problem by suggesting a novel and universal method that can be implemented in current P2P networks. We show that by separating nodes into two groups of seeders and leechers and then implementing a simple pattern for seeders, we can improve fairness in P2P networks. Even though our algorithm is universal and not limited to a specific protocol, by implementing it on BitTorrent we show how it can be used in practice and how effective it is.