Dynamic Skyscraper Broadcasts for Video-on-Demand

Abstract

Skyscraper Broadcasting is a recently proposed statically scheduled broadcast technique for video-on-demand that addresses the network-I/O bottleneck to provide significantly superior performance over previous approaches. This paper defines a scheme for dynamically scheduling the objects that are broadcast on the skyscraper channels. The dynamic broadcasting scheme is designed to provide all clients with the precise time at which their requested object will be broadcast, or an upper bound on that time if the delay is small. New segment size progressions are proposed that not only improve dynamic scheduling, but also simplify the server disk layout problem and allow clients with inexpensive (single-tuner, limited storage) settops to receive skyscraper broadcasts. Preliminary simulation results show that the proposed dynamic scheme (1) provides factors of two or more improvement in mean client waiting time, (2) outperforms the static system with respect to variability in client waiting time, and (3) delivers reasonable service to clients with inexpensive settops while providing clients that have more expensive settops with a high level of service that is relatively isolated from detrimental performance impact from the diskless clients.

This research was partially supported by the National Science Foundation under Grant HRD-9896132, and by the Natural Sciences and Engineering Research Council of Canada under Grant OGP-0000264.