Video on demand over WDM networks

Owing to the traffic characteristics of a video-on-demand (VOD) system, it is very attractive to use the isochronous service for VOD traffic transmission. This paper proposes a mechanism which uses an isochronous service to support a video-on-demand service over WDM networks. Based on the proposed mechanism, the problem of scheduling isochronous and asynchronous traffic with a variable number of receivers and transmitters for single-star WDM networks is investigated. For only asynchronous traffic, an optimal scheduling algorithm is presented; for both isochronous and asynchronous traffic, a heuristic algorithm is proposed for the single-star WDM networks with multiple receivers and transmitters. Simulation results show that the average switching duration and the average number of switching modes obtained by the proposed algorithm are efficient.