A DISPERSÃO DE DADOS COMO CRITÉRIO PARA A POLÍTICA DE SELEÇÃO DE PEERS EM UMA REDE BITTORRENT PARA STREAMING SOB DEMANDA INTERATIVO

Este artigo analisa o impacto da dispersão de dados na política de seleção de peers de uma rede BitTorrent utilizada para o serviço de streaming sob demanda interativo. Para tanto, a política original de seleção de peers do protocolo BitTorrent é modificada com o intuito de priorizar aqueles peers que menos introduzem dispersão. Em seguida, através de simulações em cenários reais de distribuição de conteúdo multimídia, a qualidade de serviço do sistema é avaliada usando diferentes métricas de desempenho. Comparado ao sistema tradicional, os resultados finais permitem conjecturar que a dispersão de dados é um importante critério a ser considerado para a seleção de peers em virtude da otimização de serviço que foi possível observar. Por exemplo, houve registro de reduções de até 34% com relação ao número de pedaços perdidos pelos clientes durante sessões de transferências de dados multimídia. Ante o exposto, a principal contribuição deste artigo é a possibilidade de implementação de protocolos de streaming sob demanda mais eficientes usando o critério da dispersão de dados

Data dispersion as a criterion for the peer-selection policy in a BitTorrent network for interactive on-demand streaming network

Este artigo analisa o impacto da dispersão de dados na política de seleção de peers de uma rede BitTorrent utilizada para o serviço de streaming sob demanda interativo. Para tanto, a política original de seleção de peers do protocolo BitTorrent é modificada com o intuito de priorizar aqueles peers que menos introduzem dispersão. Em seguida, através de simulações em cenários reais de distribuição de conteúdo multimídia, a qualidade de serviço do sistema é avaliada usando diferentes métricas de desempenho. Comparado ao sistema tradicional, os resultados finais permitem conjecturar que a dispersão de dados é um importante critério a ser considerado para a seleção de peers em virtude da otimização de serviço que foi possível observar. Por exemplo, houve registro de reduções de até 34% com relação ao número de pedaços perdidos pelos clientes durante sessões de transferências de dados multimídia. Ante o exposto, a principal contribuição deste artigo é a possibilidade de implementação de protocolos de streaming sob demanda mais eficientes usando o critério da dispersão de dados.http://www.revistas.unifacs.br/index.php/rs

Capacity of P2P on-demand streaming with simple, robust and decentralized control

The performance of large-scaled peer-to-peer (P2P) video-on-demand (VoD) streaming systems can be very challenging to analyze. In practical P2P VoD systems, each peer only interacts with a small number of other peers/neighbors. Further, its upload capacity may vary randomly, and both its downloading position and content availability change dynamically. In this paper, we rigorously study the achievable streaming capacity of large-scale P2P VoD systems with sparse connectivity among peers, and investigate simple and decentralized P2P control strategies that can provably achieve close-to-optimal streaming capacity. We first focus on a single streaming channel. We show that a close-to-optimal streaming rate can be asymptotically achieved for all peers with high probability as the number of peers N increases, by assigning each peer a random set of Θ(log N) neighbors and using a uniform rate-allocation algorithm. Further, the tracker does not need to obtain detailed knowledge of which chunks each peer caches, and hence incurs low overhead. We then study multiple streaming channels where peers watching one channel may help in another channel with insufficient upload bandwidth. We propose a simple random cache-placement strategy, and show that a close-to-optimal streaming capacity region for all channels can be attained with high probability, again with only Θ(logN) per-peer neighbors. These results provide important insights into the dynamics of large-scale P2P VoD systems, which will be useful for guiding the design of improved P2P control protocols. © 2013 IEEE.published_or_final_versio

On the Optimization of BitTorrent-Like Protocols for Interactive On-Demand Streaming Systems

This paper proposes two novel optimized BitTorrent-like protocols for interactive multimedia streaming: the Simple Interactive Streaming Protocol (SISP) and the Exclusive Interactive Streaming Protocol (EISP). The former chiefly seeks a trade-off between playback continuity and data diversity, while the latter is mostly focused on playback continuity. To assure a thorough and up-to-date approach, related work is carefully examined and important open issues, concerning the design of BitTorrent-like algorithms, are analyzed as well. Through simulations, in a variety of near-real file replication scenarios, the novel protocols are evaluated using distinct performance metrics. Among the major findings, the final results show that the two novel proposals are efficient and, besides, focusing on playback continuity ends up being the best design concept to achieve high quality of service. Lastly, avenues for further research are included at the end of this paper as well.Comment: 20 page

Janelas para seleção de blocos visando à adaptação do protocolo bittorrent para vídeo sob demanda

Diferentes técnicas de seleção de blocos têm sido desenvolvidas a fi m de adequar o protocolo BitTorrent para o serviço de Vídeo sob Demanda. Nesse contexto, este artigo apresenta quatro abordagens baseadas em janelas de seleção de blocos recentemente publicadas na literatura. Além da explicação e análise individual de cada uma dessas abordagens, são realizadas comparações de desempenho baseadas nos resultados observados. No final, também são propostas sugestões para o desenvolvimento de trabalhos futuros

BitTorrent-Like Protocols for Interactive Access to VoD Systems

This article presents two novel protocols for interactive access to video-on-demand systems. They are both based on the well-known BitTorrent paradigm. As main innovative aspects, the video chunks are categorized in different priority sets and there is the deployment of a user-behavior predicting model. The analysis and the validation are carried out through simulations using workloads from a real server. Furthermore, the novel protocols are compared with others of the literature. The final results outline optimizations of up to one order of magnitude over the various competitive metrics considered herein

Capacity of p2p on-demand streaming with simple, robust and decentralized control

Abstract-The performance of large-scaled peer-to-peer (P2P) video-on-demand (VoD) streaming systems can be very challenging to analyze. In practical P2P VoD systems, each peer only interacts with a small number of other peers/neighbors. Further, its upload capacity may vary randomly, and both its downloading position and content availability change dynamically. In this paper, we rigorously study the achievable streaming capacity of large-scale P2P VoD systems with sparse connectivity among peers, and investigate simple and decentralized P2P control strategies that can provably achieve close-to-optimal streaming capacity. We first focus on a single streaming channel. We show that a closeto-optimal streaming rate can be asymptotically achieved for all peers with high probability as the number of peers N increases, by assigning each peer a random set of Θ(log N ) neighbors and using a uniform rate-allocation algorithm. Further, the tracker does not need to obtain detailed knowledge of which chunks each peer caches, and hence incurs low overhead. We then study multiple streaming channels where peers watching one channel may help in another channel with insufficient upload bandwidth. We propose a simple random cache-placement strategy, and show that a close-to-optimal streaming capacity region for all channels can be attained with high probability, again with only Θ(log N ) per-peer neighbors. These results provide important insights into the dynamics of large-scale P2P VoD systems, which will be useful for guiding the design of improved P2P control protocols

BitTorrent-Like Protocols for Interactive Access to VoD Systems

This article presents two novel protocols for interactive access to video-on-demand systems. They are both based on the well-known BitTorrent paradigm. As main innovative aspects, the video chunks are categorized in different priority sets and there is the deployment of a user-behavior predicting model. The analysis and the validation are carried out through simulations using workloads from a real server. Furthermore, the novel protocols are compared with others of the literature. The final results outline optimizations of up to one order of magnitude over the various competitive metrics considered herein

On the optimization of bittorrent-like protocols for interactive on-demand streaming systems

This paper proposes two novel optimized BitTorrent-like protocols for interactive multimedia streaming: the Simple Interactive Streaming Protocol (SISP) and the Exclusive Interactive Streaming Protocol (EISP). The former chiefly seeks a trade-off between playback continuity and data diversity, while the latter is mostly focused on playback continuity. To assure a thorough and up-to-date approach, related work is carefully examined and important open issues, concerning the design of BitTorrent-like algorithms, are analyzed as well. Through simulations, in a variety of near-real file replication scenarios, the novel protocols are evaluated using distinct performance metrics. Among the major findings, the final results show that the two novel proposals are efficient and, besides, focusing on playback continuity ends up being the best design concept to achieve high quality of service. Lastly, avenues for further research are included at the end of this paper as well