BitTorrent Network Research Articles

BitTorrent Network Traffic Forecasting With ARMA

BitTorrent Network Traffic Forecasting With ARMA

Denial-of-service attacks and countermeasures on BitTorrent

BitTorrent has been widely used for the efficient distribution of files, such as digital content and media files, to very large numbers of users. However, previous work has exposed vulnerabilities in the protocol and demonstrated that they can be exploited to perform severe Denial-of-Service (DoS) attacks against BitTorrent networks. Earlier, we proposed two novel algorithms as countermeasures to particularly effective attacks, mitigating the problem, and evaluated through simulation. The present paper reviews the attacks previously identified and the countermeasure algorithms, experimentally evaluating their operation through both simulation and experiments on live BitTorrent swarms. Both simulation and experimental results observed with the implementation of attacks and countermeasures indicate that the algorithms are effective in holding DoS attacks and efficient when attacks are not present.

Exploiting scheduling and free‐riding for offline downloading in BitTorrent networks

SUMMARYRecently, the peer‐to‐peer (P2P) architecture has become a popular scheme for Internet users to rapidly exchange files. As reported in previous studies, P2P traffic accounts for a significant portion of overall Internet traffic. Many computing resources, for example, network bandwidth and disk space, may be consumed by P2P clients. Accordingly, in this paper, we devise a novel scheme that integrates advantageous features of both the conventional client–server and the P2P architectures to create an offline downloading service. Specifically, the proposed service acts as an agent that downloads required files from the BitTorrent network without consuming local computing resources. In other words, users can stay offline during the download process. Because the proposed scheme aims to provide service to numerous users at the same time, a proper scheduling technique is adopted to achieve better download performance. Moreover, a free‐riding mechanism is seamlessly incorporated with the proposed priority queuing to facilitate more effective bandwidth utilization. Empirical studies show that our scheme is promising in practical applications. Copyright © 2012 John Wiley & Sons, Ltd.

Uncover the peer distribution in BitTorrent

Peer-to-peer traffic constitutes more than 60% of today’s Internet traffic, resulting in high band-width cost for ISPs. Recent efforts have been made to modify BitTorrent clients to reduce inter-ISP traffic. Although the results have been encouraging, recent research also reveals that global adaptation of such an approach may harm the download time as there is no clear evidence of persistent clustering in all ISPs. To this end, many large scale measurements on BitTorrent topology have been conducted by analyzing differ-ent snapshots of the BitTorrent network. However, the analysis overlooked the download time, the actual contributions of peers, and the distribution of peers throughout the file download period since the snapshots were obtained by querying the tracker for IP addresses of peers at a certain time. In this paper, we seek to understand to what extent the distribution of peers in BitTorrent relates to their contributions in data swarm-ing and transmission rates by studying real BitTorrent download traces. In order to present an unbiased view, we collected the traces from over 100 different files, including books (in different languages), music (in different languages), movies, and software (for different operating systems). The file size ranges from 4 MB to 4 GB. We also compared traces from a regular BitTorrent client with an ISP-friendly BitTorrent client to examine the actual impact of an ISP-friendly algorithm on download time and peer contributions. Our major findings include that distance has no effect on the download rate in general, seeds or lechers cannot always be found within the same ISP, and a torrent can only benefit from an ISP-friendly approach in certain situa-tions. Suggestions are given on how BitTorrent clients can be more ISP-friendly without sacrificing download rate.

Modeling the initial stage of a file sharing process on a BitTorrent network

In this paper, we model the number of seeders during the initial stage of a file sharing process on BitTorrent networks. The initial stage is crucial for successfully identifying the initial seeder, who provided the source of the files on the Internet. Most existing BT models focus on different parameters in the steady state, which occurs at a later stage of a file sharing process. None of them are able to characterize the initial stage. In this study, we propose the first model on capturing the characteristics on the growth of the number of seeders during the initial stage on a BT network. Also, we derive a lower bound for the appearing time of the second seeder and the length of the stationary period. Our model suggests that the number of seeders remain stationary during the starting period of a file sharing process. When it enters the rapid-rising period, it increases more speedily as an increasing number of seeders are available for supplying the rarest pieces. The observed demarcation of the stationary period and the rapid-rising period is significant in identifying the initial seeder on a BT network. If the investigative work can be commenced within the stationary period, the chance of identifying the initial seeder is much higher. On the other hand, if the file distribution has entered the rapid-rising period, one can no longer determine which of the existing seeders is, indeed, the initial seeder.

Implementation and analysis of the BitTorrent protocol with a multi-agent model

A peer to peer (P2P) computer network relies on direct connections between participants instead of conventional centralized resources. This kind of network is useful for many purposes, but its 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 agent that interacts with other agents and reacts autonomously, following the same decision algorithms as a real client. The clients aim at downloading content files in the shortest time possible and they share them with other agents. The model is programmed in JADE, a software framework in Java language for agent development. The model has been validated by initial tests, and it will be used to study the behavior of BitTorrent networks in diverse situations that are hard to emulate in a real network, or to simulate with other models, like modifications of the protocol or user behaviors.

Optimizing peer selection in BitTorrent networks with genetic algorithms

BitTorrent has emerged as an effective peer-to-peer application for digital content distribution in the Internet. However, selecting peers in BitTorrent for efficient content distribution still poses a number of challenges due to high heterogeneities of peers with varied rates of uploading bandwidth and dynamic content. This paper presents GA-BT, a genetic algorithm based peer selection optimization strategy for efficient content distribution in BitTorrent networks taking into account both the uploading bandwidth of peers and the availability of content among peers. GA-BT employs the divisible load theory to dynamically predict optimal fitness values to speed up the convergence process in producing optimal or near optimal solutions in peer selection. A BitTorrent simulator is implemented for GA-BT performance evaluation, and the experimental results show the effectiveness of GA-BT in peer selection optimization.

Idle Users Management for Improved BitTorrent Performance

In the past few years, there have been tremendous interest in the peer-to-peer(P2P) content delivery. This communication paradigm dramatically increases the traffic over inter-ISP links. In particular, BitTorrent(BT), the most popular P2P application, generates a huge amount of traffic on the Internet. BitTorrent’s performance is limited by the fact that typical internet users have much lower upload bandwidths than download bandwidths. This results in the overall average download speed of a BitTorrent-like file download system to be bottle-necked by the much lower upload capacity. We think about to utilize idle users’ spare upload capacity to largely improve the download speed beyond what can be achieved in a conventional BitTorrent network. In this paper, we design a system that is completely compatible with the already existing clients who conform to the BitTorrent protocol, at the same time, we analyze this system’s steady-state performance and present simulation results.

Enhancing tit-for-tat for incentive in BitTorrent networks

BitTorrent achives great success in its high performance for file distribution. It is commonly believed that this owes to Tit-for-Tat strategy adopted in choking algorithm for incentive in BitTorrent protocol. But there are still many issues in incentive mechanism in BitTorrent. In this paper, we study Tit-for-Tat strategy by constructing a game model in P2P environments and deducing the constraint under which the strict Tit-for-Tat is an equilibrium strategy. We then enhance and adapt the Tit-for-Tat strategy to the dynamic property in P2P networks, and deduce the constraint under which it is still an equilibrium strategy. We also study through simulations the performance improvement of the enhanced Tit-for-Tat, and give suggestion on how to choose proper system parameters under different network conditions. Finally, based on the enhanced Tit-for-Tat strategy, we propose a method to improve incentive in BitTorrent networks to cope with free-riding and fairness issues.

CBT: A proximity-aware peer clustering system in large-scale BitTorrent-like peer-to-peer networks

In a large-scale BitTorrent-like peer-to-peer file sharing system, the track server could be overloaded to update the state information of constantly arriving and leaving peers. Upon the connection request from a peer, the track server responses with a random list of peers and such randomly selected peers among the whole peer-to-peer network could create a long delay of file sharing between two peers. To improve the file sharing performance, we propose a hierarchical architecture to group peers into clusters according to their proximity in the underlying overlay network in such a way that clusters are evenly distributed and that the peers within each cluster are relatively close to each other. We achieve this by constructing the CBT (Clustered BitTorrent) system with two novel algorithms: a peer joining algorithm and a super-peer selection algorithm. We develop a fluid model to compare the performance of the proposed CBT system with a original BitTorrent system. With this model, we find that the CBT system quite effectively improves the performance of the system. Finally, simulation results are given, which demonstrate that the CBT system achieves better results than a randomly organized BitTorrent network, improving the system scalability and efficiency while retaining the robustness and incentives of the original BitTorrent paradigm.

Special Issue: Recent Advances in Peer‐to‐Peer Systems and Security

Peer-to-peer systems have revolutionized the way we store 1, 2, disseminate 3, 4 and share 5, 6 content. In recent years, researchers have examined numerous aspects of these innovative architectures and proposed numerous protocols and applications. While peer-to-peer research has impacted a number of areas, including theory, networking, databases and distributed systems, recent work has focused more on the issues of practical, deployable systems, measurements, and issues of security and privacy in peer-to-peer applications. This issue brings together recent work on several projects focused on building robust, practical peer-to-peer systems. The work described has also been presented at the 5th international workshop on peer-to-peer systems (IPTPS 2006), an annual forum for researchers and practitioners of large distributed systems, held in Santa Barbara, California, and attended by more than 80 participants. The goal of the workshop was to examine peer-to-peer technologies, applications and systems, and to identify key research issues and challenges that lie ahead. In the context of this workshop, peer-to-peer systems were characterized as being decentralized, self-organizing distributed systems, in which all or most communication is symmetric. This issue includes five papers, two of which 7, 8 present novel approaches to enhance the efficiency of current file-sharing networks, while the other three 9-11 examine security-related issues including reputations, incentives and misbehaving users. In the first paper, Epema et al. 7 propose Tribler, a new content-sharing protocol that leverages social relationships to enhance performance. While Tribler leverages BitTorrent's downloading mechanism, it is primarily a social network, where users obtain persistent, long-term identities, and self-organize according to their preferences and operational history. By leveraging shared interests, Tribler encourages users to behave altruistically, and shows that with willing helpers, downloaders can dramatically reduce their download latencies. The second paper 8 proposes the novel application of a probabilistic counting algorithm to hybrid search. To estimate whether a file is popular, the authors propose that super-peers count its occurrence by applying the Flajolet–Martin algorithm, where each member of a set flips a fair coin up to N times, and counts the number of heads seen before the first tail. The maximum value from all members is an approximate count of the set size. The remaining papers discuss issues closely related to reputations and user behavior. In the first paper, Swamynathan et al. 11 examine one of the challenges of applying reputation systems to peer-to-peer networks, that of short session histories. She proposes a proactive reputation scheme that allows peers to actively probe and test unknown peers with sample requests, all while making the probes indistinguishable from normal transactional requests and remaining anonymous. Second, Lian et al. 9 show using measurements that in the presence of colluding users, global reputation systems such as EigenTrust can produce non-ideal results. They propose instead a multi-trust reputation approach that bridges the gap between personal trust and global trust, and shows how it addresses the issues of collusion behavior found in current peer-to-peer networks. Finally, Liogkas et al. 10 explore the effectiveness of incentive and enforcement mechanisms in the popular BitTorrent network by implementing and evaluating three different exploits. They evaluate their strategies on both private and public BitTorrent networks, and present some surprising results.

File sharing activities over BT Networks

Pirated movies are available for sale at low prices in many online stores such as eBay and MovieGoods. But a new way of distributing pirated movies based on Peer-to-Peer (P2P) networks, in particular BitTorrent (BT), which can cause even greater financial losses to the movie industry, has surged in popularity. The financial losses to the movie industry due to P2P can be more severe and long-lasting because (1) distributing the digital form of pirated movies is much easier; (2) copyright holders or movie publishers can do very little to prevent distribution over P2P networks, and they usually respond passively; and (3) pirated movies exist even before their official release since the Telesync (TS) version of movies shot in the cinema can be easily produced. For the movie industry to come up with an effective anti-piracy strategy to combat BT networks, it is necessary to understand the sharing activity of pirated movies in BT. This article presents data collected from two representative BT discussion groups to explain the file-sharing patterns of pirated movies over BT networks and to analyze their impact on other movies in the same series. "The Lord of The Rings" was chosen for our study. We were amazed at the speed that this unreleased Hollywood movie became available for download in BT. So our study is intended to generate insights as to when BT users began to show interest in the movie, to think about downloading it, to actually download and play the movie, and finally to leave BT undetected. This article concludes with suggestions on the design of an anti-piracy strategy.