At present, a demand to the technology of contents distribution by which each user can request the desired content through network is increasing. There are some merits and demerits respectively with the existing on-demand systems for contents distribution, such as the methods based on broadcast and select transfer or multicast one. In this paper, we propose a hybrid scheduling method which adaptively uses both broadcasting and multicasting in order to improve the system efficiency. Adequate channel boundary to adopt two different transfer mechanisms is found through analytical consideration. Also, performance improvement of our proposal is verified in terms of response time and request blocking rate through computer simulation.

There is an increasing demand for the technology of content distribution, by which each user can request desired content through a network. Because of the low efficiency of existing systems, we proposed a new block transfer type video distribution system called Burst VoD. The Burst VoD system aggressively utilizes multicasting, and divides the content data into a mass of block files, which it periodically transmits to a terminal through a high-speed network, using a higher rate than the playback speed. However, by using the scheduling algorithm of the Burst VoD system, when users request the same content from different periods, the VoD server repeatedly transmits the same block files in different periods. In this paper, we propose an advanced scheduling algorithm based on the Burst VoD system to improve its multicasting efficiency. In addition, we propose a multi-channel BurstVoD in order to reduce the interface bandwidth of client.