PALESTRA

 

Prof. Jussara M. Almeida

Universidade Federal de Minas Gerais – DCC/UFMG

 

Palestra: Dia 16/09/05 das 10:15 às 11:15 – Sala H - 301

 

Scalable Media Streaming to Interactive Users

Abstract - Recently, a number of scalable stream sharing protocols have been proposed with the promise of great reductions in the server and network bandwidth required for delivering popular media content. Although the scalability of these protocols has been evaluated mostly for sequential user accesses, a high degree of interactivity has been observed in the accesses to several real media servers. Moreover, some studies have indicated that user interactivity can severely penalize the scalability of stream sharing protocols.

This presentation investigates alternative mechanisms for scalable streaming to interactive users. We first identify a set of workload aspects that are determinant to the scalability of classes of streaming protocols. Using real workloads and a new interactive media workload generator, we build a rich set of realistic synthetic workloads. We evaluate Bandwidth Skimming and Patching, two state-of-the-art streaming protocols, covering, with our workloads, a larger region of the design space than previous work.  Finally, we propose and evaluate five optimizations to Bandwidth Skimming, the most scalable of the two protocols. Our best optimization reduces the average server bandwidth required for interactive workloads in up to 54%, for unlimited client buffers, and 29%, if buffers are constrained to 25% of media size.

A Profa. Jussara M. Almeida é Bacharel e Mestre em Ciência da Computação, pela Universidade Federal de Minas Gerais (UFMG), com títulos obtidos em 1994 e 1997, respectivamente. Em agosto de 1997, ela iniciou seus estudos na University of Wisconsin-Madison, nos EUA. Obteve os títulos de M.Sc. e Ph.D. em Computer Science por aquela universidade em 1999 e 2003, respectivamente. Desde 2004, é Professora Adjunto no Departamento de Ciência da Computação da UFMG. Seus principais interesses de pesquisa incluem análise e modelagem de desempenho de grandes sistemas distribuídos, com foco particular em distribuição de vídeo e áudio, e comportamento malicioso em sistemas de e-mails e em sistemas P2P.