隨著時代進步與網路技術發展，在網際網路上傳輸連續多媒體資料如聲音與影片愈來愈受歡迎，因此許多的多媒體伺服器便因應而生，隨選視訊（Video on Demand）服務也愈來愈流行。對一影片供應者來說，如何在有限的影片伺服器容量和網路頻寬下滿足最大多數的使用者、在最短的等待時間內看到想看的影片，是一個重要議題。所以一般排序策略會依據影片受歡迎程度和使用率來做影片服務的排程先後順序，然而此種情況下，可能會讓使用者在經過漫長的等待之後仍然無法取得系統服務的權利，進而離開了隨選系統，因此一個好的影片排序政策應該降低使用者離開之機率與等待服務的時間。常見的排序政策有first-come-first-served (FCFS)、maximum queue length (MQL)、maximum factor queue length (MFQL)等策略，但上述之方法都可能讓系統在選取所要服務的影片時，產生重複選到同一部影片的狀況，進而讓選取其他影片之使用者無法取得系統的服務，然後離開隨選系統的環境，所以在本篇論文中，我們提出一個方法，稱之為scheduling policy with bandwidth balancing (SPBB)，盡量讓使用者能取得自己所要求的影片，降低使用者離開系統的機會，藉此來提高隨選視訊系統的整體效能，而此方法會結合在DQDB網路上頻寬分配與平衡的觀念，以期達到我們的目的。

As streaming video and audio over the Internet become popular, the deployment of a large-scale multimedia streaming application requires an enormous amount of server and network resources. In a video-on-demand environment, batching of video requests are often used to reduced I/O demand and improve throughput. Since users may leave if they experience long waits, a good video scheduling policy needs to consider not only the batch size but also the user defection probabilities and wait times. The common scheduling policies are the first-come-first-served (FCFS), the maximum queue length (MQL), and the maximum factored queue length (MFQL). But these schemes may choose the same video and serve the same video requests. Users choosing other video can not receive the video segment and may leave after waiting a long time.
In this paper, we propose a batching policy that schedules the video with the concept of the bandwidth balancing scheme in DQDB networks. We refer to this as the SPBB policy. Our goal is to make sure that users can get the video segment and don’t leave the video-on-demand system.

Chapter 1 序論...................................1
1.1 前言..........................1
1.2 研究動機......................3
1.3 研究目的......................4
1.4 論文架構......................4
Chapter2 相關文獻探討...........................6
2.1 改善效能方式..................7
2.2 資源共享策略..................8
2.3 影片排序策略.................11
2.4 DQDB網路頻寬分配平衡概念.....18
Chapter3 設計研究方案-SPBB.....................21
3.1 構想方法概念.................22
3.2 影片排序策略SPBB設計.........24
Chapter4 模擬實驗..............................29
4.1 系統效能指標定義.............30
4.2 模擬實驗評估.................31
4.2.1 Defection probability........32
4.2.2 Average delay time...........33
4.2.3 Unfairness...................34
4.2.4 Different priority factor....35
Chapter5 結論..................................49
參考文獻................................................51

[1] C.C Aggarwal, J.L. Wolf, P.S. Yu, “On optimal batching policies for video-on-demand storage servers” Multimedia Computing and Systems, 1996., Proceedings of the Third IEEE International Conference on 17-23 June 1996 Page(s):253 - 258
[2] C. C. Aggarwal, J. L.Wolf, and P. S. Yu, “The Maximum Factor Queue Length Batching Scheme for Video-on-Demand Systems” IEEE Trans. on Computers, 50(2): 97-110, February2001
[3] A. Dan, D. Sitaram, and P. Shahabuddin, “Scheduling Policies for an On-Demand Video Server with Batching” In Proc. of the ACM Conf. on Multimedia, pages 391-398, October 1994
[4] A. Dan, D. Sitaram, and P. Shahabuddin, “Dynamic batching policies for an on-demand video server,” Multimedia Syst., vol. 4, pp.112–121, June 1996.
[5] A. Dan, P. Shahabuddin, D. Sitaram, and D. Towsley “Channel Allocation under Batching and VCR Control in Movie-on-Demand Servers” Journal of Parallel and Distributed Computing, 30(2): 168-179, November 1995.
[6] R. Flynn, and W. Tetzlaff. “Disk Striping and Block Replication Algorithms for Video File Servers” In Proc. of the Int’l Conf. on Multimedia Computing and Systems, pages 590-597, June 1996.
[7] L. Golubchik, J. C. S. Lui, and R. Muntz, “Reducing I/O Demand in Video-On-Demand Storage Servers“ In Proc. of the ACM SIGMETRICS Conf. on Measurements and Modeling of Computer Systems, pages 25-36, May 1995
[8] J. L. L. Golubchik and R. Muntz, “Adaptive piggybacking: A novel technique for data sharing in video-on-demand storage servers,” in Multimedia Syst., vol. 4, 1996, pp. 140–155.
[9] K. A. Hua, Y. Cai, and S. Sheu, “Patching: A Multicast Technique for True Video-on-Demand Services” In Proc. of ACM Multimedia, pages 191-200, September 1998
[10] E.L. Hahne, A.K. Choudhury, N.F Maxemchuk, “DQDB networks with and without bandwidth balancing Communications” IEEE Transactions on Volume 40, Issue 7, July 1992 Page(s):1192 - 1204
[11] E.L. Hahne, N.F. Maxemchuk, “Fair access of multi-priority traffic to distributed-queue dual-bus networks” INFOCOM '91. Proceedings. Tenth Annual Joint Conference of the IEEE Computer and Communications Societies. Networking in the 90s. IEEE 7-11 April 1991 Page(s):889 - 900 vol.2
[12] K.A. Hua, M.A. Tantaoui, W. Tavanapong, “Video delivery technologies for large-scale deployment of multimedia applications” Proceedings of the IEEE Volume 92, Issue 9, Sept. 2004 Page(s):1439 – 1451
[13] S. Jamin, S. Shenkar, L. Zhang, and D. D. Clark, “An admission Control Algorithm for Predictive Real-Time Service” In Proc. of the Int’l Workshop on Network and Operating System Support for Digital Audio and Video, pages 349-356, November 1992
[14] L. Juhn and L. Tseng, “Harmonic Broadcasting for Video-on-Demand Service” IEEE Trans. on Broadcasting, 43(3): 268-271, September 1997.
[15] A. L. N. Reddy, J. Wyllie. “Disk Scheduling in a multimedia I/O system” In Proc. of the ACM Conf. on Multimedia, pages 225-233, August 1993.
[16] N. J. Sarhan and C. R. Das. “Adaptive Block Rearrangement Algorithms for Video-On-Demand Servers.” In Proc. of Int’l Conf. on Parallel Processing, pages 452-459, September 2001.
[17] N. J. Sarhan and C. R. Das. “A Detailed Study of Request Scheduling in Multimedia Systems.” Technical Report CSE-03-002, Computer Science and Engineering, The Pennsylvania State University, January 2003.
[18] Nabil J. Sarhan and Chita R. Das, “A simulation-based analysis of scheduling policies for multimedia servers” Simulation Symposium, 2003. 36th Annual, page(s):183 – 190, 30 March-2 April 2003
[19] P. Shenoy, and V. Harric. “Efficient Striping Techniques for Variable Bit Rate Continuous Media File Servers.” Performance Evaluation Journal, 38(2): 175-199, December 1999
[20] H. Shachnai and P. S.Yu, “Exploiting Wait Tolerance in Effective Batching for Video-on-Demand Scheduling” Multimedia Systems, 6(6): 382-394, 1998
[21] A. K. Tsiolis and M. K. Vernon. “Group-Guaranteed Channel Capacity in Multimedia Storage Servers.” In Proc. of the ACM SIGMETRICS Conf. on Measurements and Modeling of Computer Systems, pages 285-297, June 1997