The Internet and web service have become the most popularly platform and application of the Client-Server model due to the universality of the network recently years. Its growth is too fast to imagine the effect, many traditional service changes into web service stage by stage, and the load of the servers become more and more heavy. In the situation the server architecture must be adapted oppositely. The web cluster architecture has the best suit of the scalability, reliability and high performance requirement, was used extensively. We have designed and implemented a mechanism termed Content-aware Distributor, which is a software module for kernel-level extension, to effectively support content-based routing. This paper is based on the achievement of the software-based Content-aware Distributor; we deliver some high repetition and fixity tasks to the hardware module, instead of the software module, to expect the hardware module could share the load of the software module and speedup the packet processing. We design and implement the hardware-based packet forwarding mechanism, by the analyze result from the software module; partition three major functions into three Engines: The Analyze Engine, which is responsible to identify and analyze the header of the packet, and decide the packet needs to be send to the upper layer or forwarded; The Lookup Engine, which is responsible to lookup the address of the table which stores the data of packet modification; and the Update Engine, used to modify the packet header as soon as possible then transfer to the send queue. We use an algorithm termed Patch to fast calculate the checksums; it causes the packet length independence modification. For the implementation, we use the Verilog HDL and EDA tools of Altera Corporation to accomplish the whole design. Simulation and evaluation the performance of processing the minimum packets, by operation at 50MHz system clock; our mechanism is faster double times than the packet receiving of two Fast Ethernet ports. From the resule we know our hardware mechanism is not only sharing the load of the upper layer, but also speedup the packet forwarding.

The Internet and web service have become the most popular platform and application of the Client-Server model due to the universality of the network recently years. Its growth is beyond the imagination, many traditional service have changed into web service stage by stage, and the load of the servers become more and more heavy. In the situation the server architecture must be adapted oppositely. The web cluster architecture that has the advantages of scalability, reliability and high performance requirement, is used extensively. In our lab developed and implemented a mechanism termed Content-aware Distributor, which is a software module for kernel-level extension, to effectively support content-based routing. Based on the achievement of the software-based Content-aware Distributor; we design and implementation a content management system for backend servers. The content management system provides a user friendly management console to allow a administrator to manage the whole cluster system. The content management system also monitors backend servers periodically, when server is awarded to be overloaded, the content management system will replicate popular content to other servers automatically. By this way cluster system can balance load of back end servers and increase system performance and throughput.

Since the speedy popularity of Internet infrastructure and explosive increasing of World Wide Web services, a lot of traditional companies had web-enabled their business over Internet and used WWW as their application platform. Those web services, such as the on-line search, e-learning, e-commence, multimedia, network service, e-government etc., need a stable and powerful web server to support the huge capability. The web hosting service becomes increasingly important in which the service providers offer system resources to store and to provide Web access to contents from individuals, institutions, and companies, who lack resources or expertise to maintain their Web site. Web server cluster is a popular architecture used by the hosting service providers as a way to create scalable and highly available solutions. However, hosting a variety of contents from different customers on such a distributed server system faces new design and management problems. This dissertation describes the work pursuing for constructing a system to address the challenges of hosting Web content on a server cluster environment. Based on the achievement of the software-based content-aware distributor, some high repetition and fixity tasks originally treated by software module are delivered to hardware module for speeding up the packet processes and for sharing the loads on the software module. Our software-based distributor is implemented in Linux kernel as a loadable module. A few system calls in user level are built to support the integration of resource management.

Due to the World Wide Web (WWW) has expanded speedily, the interaction between the user and the Web site is becoming persistently. Most proposed load control schemes developed based on the traditional Web site providing static files are not suitable for the Web site today. The new generation of WWW provides more varied and secure services. The greater part of applications are belonging to the session-based service. In order to provide better quality of services for the users, Web cluster architecture becomes the popular solution for most Web sites. This architecture combines serveral servers to work together and deals satisfied with the exponential increasing in service on WWW. In this paper, we proposed a session-based admission control and load balancing mechanism for Web cluster systems. The admission control scheme is used to prevent Web system from becoming overload by determining whether an establishment of TCP connection is admitted or not. The load balancing scheme assigns new sessions to the suitable back-end server and achieves good load balancing among back-end servers, which also increases the throughput of system. The simulation results demonstrate that our mechanism utilizes system resource efficiently and takes system utilization and percentage of completed session into account simultaneously. Therefore, our mechanism can ensure the sessions would not be aborted midway. To compare with others, our mechanism can attain higher throughput and maintain the request average delay time. Furthermore, whether the back-end servers are identical in capacity or not, their load always get good balance.