322 research outputs found
System analysis of a Peer-to-Peer Video-on-Demand architecture : Kangaroo
Architectural design and deployment of Peer-to-Peer Video-on-Demand (P2PVoD) systems which support VCR functionalities is attracting the interest of an increasing number of research groups within the scientific community; especially due to the intrinsic characteristics of such systems and the benefits that peers could provide at reducing the server load. This work focuses on the performance analysis of a P2P-VoD system considering user behaviors obtained from real traces together with other synthetic user patterns. The experiments performed show that it is feasible to achieve a performance close to the best possible. Future work will consider monitoring the physical characteristics of the network in order to improve the design of different aspects of a VoD system.El disseny arquitectĂČnic i el desplegament de sistemes de VĂdeo sota Demanda "Peer-to-Peer" que soporten funcionalitats VCR estĂ captant l'interĂšs d'un nombre creixent de grups de recerca a la comunitat cientĂfica, degut especialment a les caracterĂstiques intrĂnsiques dels mencionats sistemes i als beneficis que els peers podrien proporcionar a la reducciĂł de la cĂ rrega en el servidor. Aquest treball tracta l'anĂ lisi del rendiment d'un sistema P2P-VoD considerant el comportament d'usuaris obtingut amb traçes reals i amb patrons sintĂštics. Els experiments realitzats mostren que Ă©s viable assolir un rendiment proper al cas mĂ©s Ăłptim. Com treball futur es considerarĂ la monitoritzaciĂł de les caracterĂstiques fĂsiques de la xarxa per a poder millorar el disseny dels diferents aspectes que formen un sistema de VoD.El diseño arquitectĂłnico y el despliegue de sistemas de Video bajo Demanda "Peer-to-Peer" que soportan funcionalidades VCR estĂĄ captando el interĂ©s de un nĂșmero creciente de grupos de investigaciĂłn dentro de la comunidad cientĂfica; especialmente debido a las caracterĂsticas intrĂnsecas de tales sistemas y a los beneficios que los peers podrĂan proporcionar en la reducciĂłn de la carga en el servidor. Este trabajo se enfoca en el anĂĄlisis de rendimiento de un sistema P2PVoD considerando el comportamiento de usuarios obtenido de trazas reales, junto a otros patrones sintĂ©ticos. Los experimentos realizados muestran que es viable lograr un rendimiento cercano al caso mĂĄs Ăłptimo. El trabajo futuro considerarĂĄ la monitorizaciĂłn de las caracterĂsticas fĂsicas de la red para poder mejorar el diseño de los diferentes aspectos que conforman un sistema de VoD
Object Distribution Networks for World-wide Document Circulation
This paper presents an Object Distribution System (ODS), a distributed system inspired by the ultra-large scale distribution models used in everyday life (e.g. food or newspapers distribution chains). Beyond traditional mechanisms of approaching information to readers (e.g. caching and mirroring), this system enables the publication, classification and subscription to volumes of objects (e.g. documents, events). Authors submit their contents to publication agents. Classification authorities provide classification schemes to classify objects. Readers subscribe to topics or authors, and retrieve contents from their local delivery agent (like a kiosk or library, with local copies of objects). Object distribution is an independent process where objects circulate asynchronously among distribution agents. ODS is designed to perform specially well in an increasingly populated, widespread and complex Internet jungle, using weak consistency replication by object distribution, asynchronous replication, and local access to objects by clients. ODS is based on two independent virtual networks, one dedicated to the distribution (replication) of objects and the other to calculate optimised distribution chains to be applied by the first network
GLive: The Gradient overlay as a market maker for mesh-based P2P live streaming
Peer-to-Peer (P2P) live video streaming over the Internet is becoming increasingly popular, but it is still plagued
by problems of high playback latency and intermittent playback streams. This paper presents GLive, a distributed
market-based solution that builds a mesh overlay for P2P
live streaming. The mesh overlay is constructed such that (i) nodes with increasing upload bandwidth are located closer to the media source, and (ii) nodes with similar upload bandwidth become neighbours. We introduce a market-based approach that matches nodes willing and able to
share the stream with one another. However, market-based
approaches converge slowly on random overlay networks, and we improve the rate of convergence by adapting our market-based algorithm to exploit the clustering of nodes
with similar upload bandwidths in our mesh overlay. We address the problem of free-riding through nodes preferentially uploading more of the stream to the best uploaders. We compare GLive with our previous tree-based streaming protocol, Sepidar, and NewCoolstreaming in simulation, and our results show significantly improved playback continuity and playback latency
Bitocast: a hybrid BitTorrent and IP Multicast content distribution solution
Dissertação apresentada para obtenção do Grau de Mestre em InformĂĄtica, pela Universidade Nova de Lisboa, Faculdade de CiĂȘncias e TecnologiaIn recent years we have observed an increased use of the Internet as a means for transmitting large content. There have been several technology attempts to attack this problem, including costly distribution networks and, more recently, peer to peer (P2P) protocols. Amongst these P2P protocols, BitTorrent has proven itself as an effective means for transmitting large content items and today enjoys great popularity.
Numerous researchers have analyzed BitTorrent and proposed concepts and models to enhance
its reliability, efficiency and fairness. Further, there are proposals to extend BitTorrent to support on-demand multimedia streaming. In this Dissertation we present Bitocast, a content distribution system that combines IP Multicast and BitTorrent protocols in order to achieve a more efficient usage of an Internet Service Providerâs network and reduce download time when serving large sets of contents to large audiences
Framework and Algorithms for Operator-Managed Content Caching
We propose a complete framework targeting operator-driven content caching that can be equally applied to both ISP-operated Content Delivery Networks (CDNs) and future Information-Centric Networks (ICNs). In contrast to previous proposals in this area, our solution leverages operatorsâ control on cache placement and content routing, managing to considerably reduce network operating costs by minimizing the amount of transit traffic and balancing load among available network resources. In addition, our solution provides two key advantages over previous proposals. First, it allows for a simple computation of the optimal cache placement. Second, it provides knobs for operators to fine-tune performance. We validate our design through both analytical modeling and trace-driven simulations and show that our proposed solution achieves on average twice as many cache hits in comparison to previously proposed techniques, without increasing delivery latency. In addition, we show that the proposed framework achieves 19-33% better load balancing across links and caching nodes, being also robust to traffic spikes
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