| Nowadays, with the high-speed improvement of the network and information technology, Internet is everywhere. People rely on the Internet to studying,communicating, shopping and entertainment as well. Subsequently, the large-scale stations holding numerous accessing sum and concurrent quantity spring up like mushrooms. These stations have to be established in the gigantic data centers which possess the ability to support corresponding accessing quantity. In order to respond considerable accessing requests, the cloud data center will provide with many servers to share processing load owing to the numerous accessing quantity and achieve the goal of responding concurrent requests simultaneously. With the respect to users, this process is invisible so that response rate and service quality turn into the simple concern. Therefore, how to make the cloud data center respond considerable requests fast jump to the hotspot.To Respond considerable requests fast is equal to enhance accessing speed, the issue of topology of data center is supposed to be concerned in the first place. Due to the continuous expanding of server amount and business size, the cloud data center demand a large-scale network topology with guaranteed bandwidth and minor cost,whose superiority will have a significant effect on enhancing speed. Secondly, the server load balancing issue will also be considered in order to increase throughput and responding speed by taking advantage of resources such as CPU and RAM. Apart from this, ensuring the Qo S of requests is critical to enhance accessing speed.In recent years, being the research hotspot in network field, SDN is evaluated as the direction of next generation internet development. It is able to control the whole network information about topology, link and host by making the control plane of traditional routers abstract into the control layer, thereby managing global network equipment and achieving the load balancing of severs and links. It can also get rid of disadvantages of hardware which has the property about the expensive load balancing,poor flexibility and single point of failure. In the meanwhile, SDN keeps the ability of implementing Qo S router strategies based on various granularity.As suggested above, in order to achieve the fast response to web requests, this paper proposed that utilize SDN as the network architecture and FAT-Tree topology which is extensively used in data center at present as the bottom. It can not only achieve the load balance more conveniently and effectively but also avoid the defectsof traditional load balancing, as well as formulate strategy to guarantee the response time for web traffic requests according to traffic types simultaneously.First of all, study SDN network architecture and Open Flow protocol about the emerging background, available scenario and differences between the traditional network. Subsequently, research the realization principle and effectuation for kinds of controllers together with the Open Flow protocol. Then, we present the common methods for cloud data center at present, the analysis to principle and relative merits of FAT-Tree topology will be emphasized. Furthermore, we study the implementation and Qo S router strategies of load balancing for data center. In the end, based on the summary of above work, this paper proposed to utilize the modified con-hash algorithm to select host for responding requests and implement load balancing in SDN controller. And then, using the Lagrange relaxation algorithm via handling globe information to select a least cost path in polynomial time which can reach the host within the prescribed delay. Through the improvement from above aspects, we can achieve the fast response to web requests more effectively. |
PDF Full Text Request