Research On Scalability In Unstructured Peer-to-Peer Networks

With the development of personal computers, Peer-to-Peer networks are widelyused in various fields and show great potential.P2P technology can greatly improve the utilization of Internet bandwidth andcomputing resources. At present, P2P file sharing applications is not only P2Pnetwork technology research hot spot, is also the network bandwidth occupied themost applications, P2P file sharing applications accounted for over40%of all Internettraffic. In unstructured peer-to-peer networks, the analysis of scalability is achallenging task due to the unpredictable nature of churn rate. Specifically, in the P2Pfile sharing applications, peers join and leave the overlay network in a dynamicfashion increase the complexity of the network and leads to a huge wastage ofbandwidth during the search for a particular file. When network size is small, theperformance of P2P systems is relatively high, however, as the network size increasesgradually, the scalability of the system become the bottleneck of restricting P2Psystem for further development.In this paper, we proposed a controlled scalability model in unstructured P2Pnetworks for achieving efficient bandwidth utilization and high scalability. In theproposed model for Peer-to-Peer file sharing networks, controlled scalability isconsidered in the initializing and stabilizing phase for the peers in the overlaynetwork. The decaying phase in which the peers leave the network indefinitely worksas in existing P2P file sharing systems. In BitTorrent model, each node is configuredas in the real world with the existing BitTorrent protocol setup by allowinguncontrolled churn rate. Choking algorithm using tit-for-tat mechanism, rarest first,endgame mode, tracker down time, flash crowd and peer down time are considered forboth BitTorrent and the proposed model simulations.Performance measures such as peer availability and scalability are analyzed andcompared with the BitTorrent system show that the proposed model overcomes theproblems of bandwidth wastage and initial time flash crowd while maintaining thescalability of the network. The controlled scalability performs well in utilizingbandwidth during the event of polluted or infected files sharing than the uncontrolledscalability in the existing unstructured P2P networks.