On the Performance of a Multicast Delivery Video-On-Demand Service with Discontinuous VCR Actions

Abstract

In most proposed architectures for Video-On-Demand (VOD) systems, the customers are serviced individually by allocating and dedicating a trans- mission channel and a set of video server resources to each customer. This approach leads to an expensive-to-operate, non-scalable system. We consider a VOD system that uses multicast delivery to service multiple customers with a single set of resources. The use of multicast requires that some interactivity and part of the on-demand nature of the system are sacrificed to achieve scalability and cost-effectiveness. Previous work has considered how VCR actions could be handled in this type of system through the provisioning of set-top box buffering. In this paper we consider a modification of the semantics of the VCR functions in order to avoid this buffering requirement. In particular we consider the provision of discontinuous VCR actions in which the duration of the action is specified in integer multiples of a specified time increment. We evaluate the performance of this system through the use of simulation and compare its performance with an individual delivery (unicast) system and a multicast system with continuous VCR actions.