BitTorrent and similar peer-to-peer file sharing applications can represent a large portion of network traffic. Despite the advantages for BitTorrent users, it can unfairly consume access link bandwidth from other user(s) and applications. It can also rapidly fill up buffers at access routers. We have used a detailed model of the BitTorrent protocol to analyze its performance and impact on real...

More than half of today’s Internet traffic is generated by P2P applications, and most of which is the BitTorrent file sharing traffic. The random neighbor selection mechanism of BT puts unprecedented pressure on the network operators and service providers. In this paper firstly we give a theoretical analysis on the impact of neighbor selection mechanism on BitTorrent performance as well as netw...

A fundamental problem with many peer-to-peer systems is the tendency for users to “free ride”—to consume resources without contributing to the system. The popular file distribution tool BitTorrent was explicitly designed to address this problem, using a tit-for-tat reciprocity strategy to provide positive incentives for nodes to contribute resources to the swarm. We show that although BitTorren...

In this thesis, we examine two important factors in the design of BitTorrent: how it chooses pieces and neighbors. We present a measurement study on the distribution and evolution of the pieces in BitTorrent. The data is collected by multiple administrated clients distributed in different parts of the network. Our results validate that the downloading policy of BitTorrent is effective, yet enha...

The Performance Evaluation Process Algebra (PEPA) language is a stochastic process algebra, generating Continuous Time Markov Chains (CTMC) to allow quantitative analysis. Protocols such as BitTorrent are highly parallel in nature, and represent one area where CTMC analysis is limited by the well-known state space problem. The number of unique states each client can exist in, and the number of ...

A peer to peer (P2P) computer network relies on direct connections between participants instead of conventional centralized resources. These networks are useful for many purposes, but the killer application nowadays is file sharing. BitTorrent is a very popular protocol for this matter. In this paper we model a BitTorrent network as a multi-agent system. In it, each BitTorrent client is an agen...

We present a trust management system tailored to the needs of the BitTorrent protocol. Unlike other trust management systems, our system is partially decentralized and assumes unstructured BitTorrent swarms. In particular, we use the tracker of each BitTorrent swarm, to compute and distribute global trust scores complementing the local trust scores maintained by each peer. Our simulation study ...

BitTorrent is a popular and scalable P2P content distribution tool. This study attempts to analyze the factors that affect the offline probability of BitTorrent peer, and express the probability using these factors. We first collect large data set of BitTorrent peers’ activities. Then we use nonlinear least-squares regression to determine the probability distribution function for each of the th...

BitTorrent users and consumer ISPs are often pictured as having opposite interests, with end-users aggressively trying to improve their download times, while ISPs throttle this traffic to reduce their costs. However, inefficiencies in both download time and quantity of long-distance traffic originate in BitTorrent randomly selecting peers to interact with. We show that biasing the link selectio...