Best-Effort Patching for Multicast True VoD Service

A multicast Video-on-Demand (VoD) system allows clients to share a server stream by batching their requests, and hence, improves channel utilization. However, it is very difficult to equip such a VoD system with full support for interactive VCR functions which are important to a growing number of Internet applications. In order to eliminate service (admission) latency, patching was proposed to enable an existing multicast session to dynamically add new clients, and requests can be served without delay if patching channels are available. A true VoD (TVoD) service should support not only zero-delay client admission but also continuous VCR-like interactivity. However, the conventional patching is only suitable for admission control. We propose a new patching scheme, called Best-Effort Patching (BEP), that offers a TVoD service in terms of both request admission and VCR interactivity. Moreover, by using a novel dynamic merging algorithm, BEP significantly improves the efficiency of TVoD interactivity, especially for popular videos. We also model and evaluate the efficiency of the dynamic merging algorithm. It is shown that BEP outperforms the conventional TVoD interaction protocols.Huadong Ma received the B.S. degree in Mathematics from Henan Normal University in 1984, the M.S. degree in Computer Science from Shenyang Institute of Computing Technology, Chinese Academy of Science (CAS) in 1990 and the Ph.D. degree in Computer Science from Institute of Computing Technology, CAS, in 1995.He is a Professor with the School of Computer Science & Technology, Beijing University of Posts and Telecommunications, China. He visited UNU/IIST as research fellow in 1998 and 1999, respectively. From 1999 to 2000, he held a visiting position in the Real-Time Computing Laboratory in the Department of Electrical Engineering and Computer Science, The University of Michigan, Ann Arbor. His current research focuses on multimedia, networking, e-commerce and computergraphics, and he has published over 70papers and 3 books on these fields. He is member of IEEE and ACM.Kang G. Shin received the B.S. degree in Electronics Engineering from Seoul National University, Korea, in 1970, and both the M.S. and Ph.D. degrees in Electrical Engineering from Cornell University, Ithaca, New York in 1976 and 1978, respectively.He is the Kevin and Nancy OConnor Professor of Computer Scienceand Founding Director of the Real-Time Computing Laboratory in the Department of Electrical Engineering and Computer Science, The University of Michigan, Ann Arbor. His current research focuses on QoS-sensitive networking and computing as well as on embedded real-time OS, middleware and applications, all with emphasis on timeliness and dependability. He has supervised the completion of 49 Ph.D. theses, and authored/coauthored over 600 technical papers and numerous book chapters in the areas of distributed real-time computing and control, computer networking, fault-tolerant computing, and intelligent manufacturing. Dr. Shin is Fellow of IEEE and ACM, and member of the Korean Academy of Engineering.Weibiao Wu received the Ph.D. degree in statistics from the University of Michigan, Ann Arbor in 2001. He is currently an Assistant professor of statistics at the University of Chicago. His research interests include probabilistic network modelling and simulation, data-base compression, asymptotic theory and statistical inference of stochastic processes.