Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Medusa: A Novel Stream-Scheduling Scheme for Parallel Video Servers | EURASIP Journal on Applied Signal Processing 2004 2 317-329 2004 Hindawi Publishing Corporation Medusa A Novel Stream-Scheduling Scheme for Parallel Video Servers Hai Jin School of Computer Science and Technology Huazhong University of Science and Technology Wuhan 430074 China Email hjin@ Dafu Deng School of Computer Science and Technology Huazhong University of Science and Technology Wuhan 430074 China Email dfdeng@ Liping Pang School of Computer Science and Technology Huazhong University of Science and Technology Wuhan 430074 China Email lppang@ Received 6 December 2002 Revised 15 July 2003 Parallel video servers provide highly scalable video-on-demand service for a huge number of clients. The conventional streamscheduling scheme does not use I O and network bandwidth efficiently. Some other schemes such as batching and stream merging can effectively improve server I O and network bandwidth efficiency. However the batching scheme results in long startup latency and high reneging probability. The traditional stream-merging scheme does not work well at high client-request rates due to mass retransmission of the same video data. In this paper a novel stream-scheduling scheme called Medusa is developed for minimizing server bandwidth requirements over a wide range of client-request rates. Furthermore the startup latency raised by Medusa scheme is far less than that of the batching scheme. Keywords and phrases video-on-demand stream batching stream merging multicast unicast. 1. INTRODUCTION In recent years many cities around the world already have or are deploying the fibre to the building FTTB network on which users access the optical fibre metropolitan area network MAN via the fast LAN in the building. This kind of large-scale network improves the end bandwidth up to 100 Mb per second and has enabled the increasing use of larger-scale video-on-demand VOD systems. Due to the high scalability the parallel video servers are often used .
