Browsing by Subject "P2P"
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Item Capacity Proportional Unstructured Peer-to-Peer Networks(2010-10-12) Reddy, Chandan RamaExisting methods to utilize capacity-heterogeneity in a P2P system either rely on constructing special overlays with capacity-proportional node degree or use topology adaptation to match a node's capacity with that of its neighbors. In existing P2P networks, which are often characterized by diverse node capacities and high churn, these methods may require large node degree or continuous topology adaptation, potentially making them infeasible due to their high overhead. In this thesis, we propose an unstructured P2P system that attempts to address these issues. We first prove that the overall throughput of search queries in a heterogeneous network is maximized if and only if traffic load through each node is proportional to its capacity. Our proposed system achieves this traffic distribution by biasing search walks using the Metropolis-Hastings algorithm, without requiring any special underlying topology. We then define two saturation metrics for measuring the performance of overlay networks: one for quantifying their ability to support random walks and the second for measuring their potential to handle the overhead caused by churn. Using simulations, we finally compare our proposed method with Gia, an existing system which uses topology adaptation, and find that the former performs better under all studied conditions, both saturation metrics, and such end-to-end parameters as query success rate, latency, and query-hits for various file replication schemes.Item Measurement and analysis of BitTorrent(Texas A&M University, 2008-10-10) Sadafal, VideshBitTorrent is assumed and predicted to be the world's largest Peer to Peer (P2P) network. Previous studies of the protocol mainly focus on its file sharing algorithm, and many relevant aspects of the protocol remain untouched. In the thesis, we conduct a number of experiments to explore those untouched aspects. We implement a BitTorrent crawler to collect data from trackers and peers, and statistically analyze it to understand the characteristics and behaviors of the BitTorrent protocol better. We find that the expected lifetime of a peer in the BitTorrent is 56.6 minutes and the activity is diurnal. Peers show strong preference towards a limited number of torrents, and 10% of torrents are responsible for 67% of traffic. The US contributes maximum number of peers to the BitTorrent and ?Torrent emerges as the favorite BitTorrent client. We measure the strength of Distributed Denial of Service (DDoS) attack using BitTorrent network and conclude that it is transient and weak. Finally we address and discuss the content locatability problem in BitTorrent and propose two solutions.Item MobiShare : mobile computing with no strings attached(2013-12) Castillo, Jason Moses; Julien, ChristineIn today’s world, technology is growing at a fast rate compared at other times. Sales have increased in the smart phone market, which has created new opportunities in pervasive computing. In pervasive computing, nodes enter and leave a network at any time. Within the network, nodes can transfer data to other nodes. The information is not retained in any static location such as a server. The mobile infrastructure requires a way to handle all the information in a dynamic way. The use of a centralized server in a mobile environment creates deterioration in the performance of obtaining information. The main goal of this paper is to provide data persistence using a “substrate” that is inherently not persistent. The data will be stored within the network for availability to all users. Saving data within a network would provide a means to obtain any type of information without relying on the source of where the data came from in the network. Users would also be able to continue downloading where they left off when they return to the network. Consider an environment where people can share music or books. For example, say that John Doe was searching for a particular song to download and in the network Jane has the song that was requested. John decides to download the song without knowing that it is from Jane. Then John decides to leave the network and the download stops. Whenever John rejoins the network the download of his song will continue where he left off, and his ability to access the information will not depend whether or not Jane is present in the network. John may retrieve the file from any other user who has the exact same file. The requested information that the user queries in a search engine will be stored as a metadata within the network, either by other nodes or a temporary server. This allows data to be obtained without relying on the "main user" or creator of the data to be present in the network. The users would also be able to retrieve the data at multiple times.Item Raising the BAR in dependable cooperative services(2013-08) Wong, Edmund Liangfei; Alvisi, LorenzoCooperative services--a term which includes any system that relies on the resources and participation of its clients to function--have proven to be a popular, naturally scalable means to disseminate content, distribute computational workloads, or provide network connectivity. However, because these services critically depend on participants that are not controlled by a single administrative domain, these services must be designed to function in environments where no participant--because of failure or selfishness--will necessarily follow the specified protocol. This thesis addresses the challenge of establishing and maintaining cooperation in cooperative services by (1) advancing our understanding of the limits to what our services can guarantee in the presence of failure, (2) demonstrating the critical role that correct participants can play in the incentives provided by the service, and (3) proposing a new notion of equilibrium that, unlike traditional notions, provides both rigorous yet practical guarantees in the presence of collusion. Furthermore, we demonstrate that our ideas can be applied to practice by designing and implementing Seer, a system that provides a scalable, reliable, and robust method for disseminating content even if participants may fail arbitrarily or deviate selfishly as a coalition.Item Resistance commons : file-sharing litigation and the social system of commoning(2011-08) Caraway, Brett Robert, 1974-; Stein, Laura Lynn, 1965-; Strover, Sharon; Cleaver, Harry M.; Mallapragada, Madhavi; Phillips, David J.This dissertation is an investigation into the practice of peer-to-peer file-sharing and the litigation campaign targeting individual file-sharers carried out by the Recording Industry Association of America (RIAA) from 2003 to 2008. The competing conceptualizations of social relations which motivate the conflict over peer-to-peer file-sharing are explored using a combination of Autonomist Marxist theory and structuration theory. Peer-to-peer file-sharing is framed as part of the social system of commoning stemming from the recent ascendancy of immaterial labor within that sector of the economy dedicated to the production and distribution of informational and cultural goods. The RIAA litigation campaign is framed as a reaction to the emergence of new forms of social relations which are seen by the content-producing industries as subversive of revenue streams premised on commodity exchange in informational and cultural goods. The history of the RIAA litigation campaign is presented in detail with careful attention given to those instances in which defendants and other interested parties fought back against RIAA legal actions. The acts of resistance within the legal arena affected the ultimate potential of the litigation campaign to control the spread of file-sharing activities. Subsequent legal campaigns which have been based on the RIAA litigation model are also examined. These later file-sharing cases have been met with similar forms of resistance which have likewise mitigated the impact of legal efforts to combat file-sharing. In addition, a survey of file-sharers is included in this research as part of an attempt to understand the relationship between legal actions targeting peer-to-peer systems and individual file-sharers and the technological and social development of peer-to-peer systems. This research argues that file-sharing litigation has proven ineffective in turning back the flood of file-sharing and may have increased the technological sophistication and community ties among file-sharers. In the end, the conflict over peer-to-peer file-sharing is cast as a manifestation of a larger dynamic of capitalist crisis as content-producing industries attempt to come to terms with the contradictory tendencies of immaterial labor and the production of common pools of digital resources.