Um framework para controle de admissão utilizando o método de diversidade de caminhos em um ambiente DiffServ

• Autor(a) principal: Mognatto Junior, Estevão Oscar
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2593
• topic: Controle de admissão; MDC; Diversidade de caminhos; Admission control; MDC; Path diversity; CNPQ::CIENCIAS EXATAS E DA TERRA::CIENCIA DA COMPUTACAO

The IP protocol is based on a model called best effort, where all packets are treated the same way, without any discrimination or explicit delivery guarantees. It was develop to deal with application without QoS (Quality of service) requirements such as e-mail and FTP (File Transfer Protocol). However, more and more communication systems are supporting different kinds of real-time transmission, such as voice over IP (VoIP), interactive TV and videoconferencing. Of course, the best effort model is not suitable to cope with these new high quality real-time communication systems, so a new model needs to be develop. The challenges of transmitting high quality streaming over best-effort networks include delay, packet loss, varying bandwidth and have led to several different approaches to efficiently support multimedia streaming applications. In this context, path diversity and MDC (Multiple Description Coding) have emerged as promising techniques for robust transmission of multimedia traffic over lossy packet networks as the Internet. Path diversity is a technique that exploits different paths available between two specific hosts in the internet. MDC is a technique where the video stream is divided into multiple sub-streams (called descriptions), such that the quality of the received video increases with the number of descriptions received. In this paper, a set of admission control disciplines was developed in a DiffServ environment which take into consideration path diversity, in which one flow can be accept using more than one single path. Our main goal is to provide the fundamental understanding of the benefits of using methodologies like MDC and path diversity together to deliver continuous media stream over the internet. The parameters for admission are the bandwidth, the request start and stop time. Our results show that the use of path diversity exhibits better QoS characteristics when compared with the traditional methodology, where the best path is always used. The experiments indicate that the approach used was able to use the network resources efficiently and to achieve a better level of request accepted as well as decreases the packet loss rate.