Architecture and Analysis of Traffic Scheduling for VOD Services in Broascast-and-Select WDM Networks

Abstract

The VOD (video on demand) service supported by BISDN over the WDM networks is emerging as one of the most promising services that may gain wide market acceptance. However, if the traffic scheduling in the WDM networks does not work well and the poor design of the VOD server induces frequent multicast transmissions, the performance of the WDM networks will decrease significantly and the QoS (quality of service) of other services will suffer a lot. In this paper, we present the architecture and analysis of traffic scheduling for VOD services in broadcast-and-select WDM networks. A VOD server follows the general structure except that the PVFS (Proxy Video File Server) is separated from the AS (Archive Server). The AS consists of control processors and network interface to maintain the retrieving hierarchy to request and transmit video segments. The AS is directly connected to the local subscribers through the switch and to the remote subscribers through the WDM network. If the PVFS can have a larger capacity. The traffic among the VOD server nodes will be reduced, the multicast ratio and the size of the multicast group will be kept small to prevent significant channel dominance due to multicast traffic. Numerical results indicate that the multicast scheduling and the capacity of PVFS have significant impact on the VOD services in the broadcast-and-select WDM networks.