Design and Implementation of Client System for Large-scale Content Delivery

大規模內容派送系統之端架構設計與研製

吳正鈺(Cheng-Yu Wu)

指導教授 ： 黃能富

國立清華大學/電機資訊學院/資訊工程學系/碩士(2011年)

https://doi.org/10.6843/NTHU.2011.00529

摘要

With the rapid development of network technology, more and more all sorts of contents are exchanged and published over the network. End-users hope to obtain content from the remote node while the content providers seek a reliable way publishing their content. A traditional Content Delivery System (CDS) was proposed adopting Client-Server model to deliver content. However, this architecture challenged to an enormous increment number of users, since all upload cost is only placed on the hosting machine. The upstream of the server-side network traffic is often a transmission bottleneck.
This thesis is based on general industrial standards to practically design and implement a complete client system of the overall content delivery system. End-users arrange the sequence of delivery job by their preference on a friendly Graphical User Interface (GUI). The client-side Engine under the table delivers contents. Not only is Client-Server model adopted, Peer-to-Peer (P2P) model is flavored into the progress of content transmission. This is known as Peer-to-Server-and-to-Peer (P2SP) model. The mixed architecture does not cause one user never complete download if a particular piece of file is no longer available from any current downloaders and it expects much traffic saved in the server-side than pure Client-Server model does.
We also evaluate the proposed system and present some experimental scenarios. The results show that with a lower receiving rate from server specified to the process of content delivery for the client system, the server system save more bandwidth. The proposed system also applied in a commercial online system. The statistics gathered from that online system show that most of contents distributed by the proposed system hardly gain the help of P2P model, since there is only one client requesting this content.

關鍵字

檔案派送 ； 同儕網路 ； 點對點檔案傳輸 ； 點對點

並列摘要

隨著網路技術的蓬勃發展，越來越多各式各樣的檔案資訊在網路世界中被交換與散佈。使用者希望取得網路遠端的資源，內容提供商也尋求一個可靠的方式散佈檔案。傳統的內容派送系統採用採用客戶端-伺服器端的模式派送網路世界中的檔案。然而，由於所有的上傳頻寬全部由中央的內容伺服器提供，這類架構在使用者人數大量增加時遭遇到了極大的挑戰。不斷增加的伺服器流量於是造成了整個系統的瓶頸。
本論文依據一般業界標準設計並實作出一個完整的內容派送系統之客戶端系統。使用者根據喜好透過圖形化使用者介面操作及安排派送任務。客戶端的引擎執行派送任務。除了傳統的客戶端-伺服器端的模式外，檔案內容的傳輸過程也加入了點對點的基礎模式。這類混合式架構稱為點對伺服器與對點模式。這種架構不會發生使用者無法完成下載的工作；與傳統的客戶端-伺服器端的模式相比，在中央伺服器端也可以省去較多的頻寬。
我們同時去評估此系統，以及提出一些實驗的情境。實驗的結果顯示當客戶端系統在下載檔案的過程中被指派較低的伺服器接收率，中央伺服器系統可節省較多的頻寬。此派送系統目前也被應用於商業產品並且正式上線運行。從該線上系統收集到數據顯示，由於大部分的檔案只有被唯一一個使用者要求下載，因此，此類案例的檔案在傳輸的過程中很難藉由點對點技術來降低伺服器的頻寬。

並列關鍵字

content delivery ； Peer-to-Peer network ； Peer-to-Peer file transfer ； Peer-to-Peer ； P2P

參考文獻

[1] Stefan Saroiu, Krishna P. Gummadi, Richard J. Dunn, Steven D. Gribble, and Henry M. Levy, “An Analysis of Internet Content Delivery Systems,” in Proceedings of the Fifth Symposium on Operating Systems Design and Implementation (OSDI 2002), Boston, MA, USA, Dec 2002.

[3] Jaison Paul Mulerikkal and Ibrahim Khalil, “An Architecture for Distributed Content Delivery Network,” IEEE International Conference on Networks, pp. 359-364, Nov 2007.

[11] Secure Hash Algorithm 1. http://tools.ietf.org/html/rfc3174

[21] R. Lo Cigno, A.Russo, and D.Carra, “On Some Fundamental Properties of P2PPush/Pull Protocols”, in Proceedings of HUT-ICCE 2008, HoiAn, Vietnam, Jun 2008.

[22] Chao Xie, Guihai Chen, Art Vandenberg, and Yi Pan, “Analysis of hybrid P2P overlay network topology”, Computer Communications, Volume 31, Issue 2, pp.190-200, Feb 2008.