Research On Web QoS Technology

With the development of the computer network and multimedia technologies, the Web application on the Internet is increasing explosively. Most of the Web applications are the HTTP requests. Many web sites had to face the problem of the server overloading. The main symptom is that users have to wait a very long time for the HTTP response and even the HTTP requests will be rejected. The responding time is generally influenced by two elements: the quantity of the service of network's transfer layer and the performance of the web server. Recently years, the research has been carried out actively in this field. In condition of the server overloading, if any measure was not taken about the QoS control in the applications layer, although the QoS of the network transferring is ensured very well, the request may also be rejected or the responding time be delayed so long that leads to "reject request" result. So we could conclude that the overload of the web server is becoming the bottleneck of the QoS control. Therefore, how to apply the web server QoS control and provide the customers the satisfied services, has become the imminence problems that must be settled.Due to the above problems, in this article we do some key research in the field. We mainly focus on the strategy of classified service, the QoS control on the web server cluster, etc. The contents of the article are as following:We study the mainstream technique and the architecture of Web QoS system, analyzing their kernel techniques. This work helps us master the latest developing trend of this field.A session-based Web QoS control strategy is proposed. By the session, customers can be classified into different classes. Different access control strategies can be imposed to the different classes customers. Higher-class customers can get more system resource, so that they can enjoy better service and faster HTTP response. A Web QoS control strategy on the web cluster system is proposed. At the front-end, the dispatcher takes a session-based load-balancing algorithm. At the back-end, the QoS control strategy will be carried out in the servers.A Linux-based prototype system of web server cluster is designed and implemented. Some technical methods studied in this dissertation are implemented and validated under the open source environment of Linux, and preliminary experimental data gained. Experiences of implementation are accumulated thorough developing the prototype of web server cluster system.