Buffered multicast routing for video-on-demand systems

Multicast communications is one of the critical techniques to enhance the video-on-demand (VOD) service scale by sharing the communication bandwidth. However, in the typical multicast communication, all receivers are expected to access the same multicast stream at approximately the same time. Therefore, only few customers can be served in the same multicast stream and additional multicast streams are required since most requests issued at different time. We propose a new multicast routing scheme to relax this time constraint, i.e. to allow the customers accessing the same multicast stream at various time. We call this new communications, buffered multicast communications. Furthermore, this type of services can be simply implemented by buffering the incoming streams on the intermediate routing nodes in a multicast tree. Based on this buffering technique, we present two buffered multicast routing algorithms. In addition, our simulation shows that the buffered multicast routing scheme tremendously reduces the transmission cost on the VOD systems. In addition, given the system resources, we derive a formula to accurately estimate the required multicast streams