An Optimal Network Scheme for On-demand Video Distribution with Asynchronous Multicasting

摘要

This paper describes a new network scheme that minimizes the consumption of network resources for on-demand streaming-video distribution through multicasting. In general, on-demand video distribution has been realized through unicasting. There have been a number of studies that attempt to reduce the load on the VOD (video on-demand) server by using multicasting, which is called Asynchronous multicast technique, but they have given little consideration of ways to reduce the whole network load. Focusing on this point, we have developed an effective network distribution technique using asynchronous multicasting. In this paper, we present a statistical traffic-control theory based on asynchronous multicasting that can be used to adjust traffic on both trunk and branch links along the distribution tree to meet the network bandwidth design requirements to ensure QOS. In addition, we propose a dynamic bandwidth-allocation and traffic-adaptation algorithm that allows finite resources to be shared among different video deliveries by assigning the available bandwidth for each according to request rates. To show the implementability of these ideas, we consider their operation with protocols that autonomously construct a multicast tree and guarantee the QOS. Simulation results supported the validity of our new traffic control theory and indicated that the dynamic bandwidth-allocation and traffic adaptation algorithm could reduce the service-blocking rate of video delivery. The algorithm, for example, lessened 17% bandwidth resource in the four kind of video contents distribution (each video length is 2 hours, transmit rate is 1 [Mbps] and average requests rate is 100 [request/hour]).