Adaptive Video on Demand Service on RSVP Capable Network

Abstract

At present, the provision of quality of service is one of the most relevant research topics. The Integrated Services approach defined by IETF and based mainly on the resource reservation protocol (RSVP [1]) is one of the issues that attracts many research work. On the other hand, research on adaptive applications [2] is another research topic. In this paper, we present a proposal that combines the features of RSVP and adaptive applications altogether. We put into work two protocols, RSVP and SVA to get an optimum resource usage for a video on demand transmission. RSVP helps to maintain a given network bandwidth available, while SVA adapts video flow taking into account not only the network impairments but the client resources variations as well. We think that it is very important to cope with the resource availability at the end systems to provide a QoS to the final user. Once a flow is being transmitted, RSVP may renegotiate the reservation to adjust the bandwidth usage. Flow adaptation is done at the video server by reducing video flow size. We choose MPEG1 format because it has a good compression factor and allows a good quality. Our mechanism may work on other video formats with hierarchical relationships among frames. SVA[3] is a protocol that interchanges information between the client and the video server. The client informs the server about how many frames per second it is able to decode and to display, then the video server adapts the video source rate while it maintains frame synchronization and sequence dependencies. The experiences we present demonstrate that a good collaboration of reservation and adaptation procedures may provide a given QoS.

1

This work has been partially funded by the Spanish Research Council under grant CICYT TEL97-1054-C03-03.