The Studies About The Flow Control When Multi-user Concurrent Accessing Based On TCP

Today's society, science and technology develop very fast, and the computer is also playing a ever-changing changes .The people who use computer become more and more , then the people have more and more demand on the Internet. With the request on Internet becoming so much, we can find the most important one of the request is the stability and accessing fluency.With the rapid development of Internet, the users who always visit the internet web become more and more, and there is more pressure on the web servers. How to face the pressure of server when a large number of users to access and download at the same time? It is a very important issue.The same problem, appears in the issue we do in the laboratory. Our task is to develop a distributed management system. On the demand side, they need to manage many documents and drawings. Using the original management methods, the documents, drawings Category and others are stored in a library. With the progress of the project development, the storage of documents, and drawing become more and more. When we need one certain type of these papers or documents, there will need to spend a lot of time to find in the document library. On the one hand, a lot of waste of much human resource, on the other hand a bad impact on the progress of the projects. In this premise, the demand side, decided to adopt the use of electronic documents to storage and management the documents, drawings, and instructed us to develop a stable and reliable document management system for their documents and drawings for the management of systematic. Demand-side present us with a number of requirements in developing the system, such as the need for management the category of documents and drawings, can be carried out in the system operation, which function should be contained in the system. At the same time, towards the end of development, access to the last paragraph of the project, we give the system to build a web site available to users to browse, download and other operations. Using the web site the users can have a more understand for the system. From the web site the users can download the update patch which is uploaded by us before to update their client. At this time, we must pay attention to the problem is that when there are many users at the same time on the site to download the upgrade patch updates the time, what should we configure our web server, in order to guarantee that we will not in high-load conditions the amount of collapse This study is one of the issues.In order to ensure the stability of our servers, the flow controlling on the transmission between the client and the server is a very important task for us. Base on the TCP transmission control protocol, we use the queuing system to solve the control of service request transmission in the Client / Server structure to achieve our objective of flow control. At first, we give the basic model of the queuing system, research and analysis the specific structure of the system and transmission mechanism, then point out the deficiencies of the system, the place which need to be improved. And then, according to our actual situation we establish a new model. Through this new model of the queuing system, we have solved the specific problems of the previous model, and also made some improvements on it. Afterwards, for a better flow control on the client/server system we have optimized the model. With the algorithm given by us which can deal with the server request into and out the queue, we have further improved our model of queuing system, and also realized the flow control much better.In this paper, we use load-balancing technology to solve the stability problem on the server. First, we introduced the concept of server load balancing, as one very effective way to solve the server load too big, defenders use it can save output with not expanding in areas server hardware. Here, we adopted two different methods of server structures, and both oh the two methods achieve a load balancing. One building we use LVS technology cluster server group, in this program, we used the three servers, and we installed the Redhat9 system, and then selected one of the three as the back-end server for loading scheduling, the other two as the outside server. On the outside one we installed the same content and services. When the users visit the actual server, the back-end server through the scheduling, dispatch the user's request to a different outside server, in order to achieve load balancing function. Another one we use the DNS server to achieve load balancing, at first we configured the DNS server , and in the DNS server we configured the two outside server in a cycle processing, then we achieve the same effect for load balancing. At last we compare the two methods with their advantages and disadvantages, and introducing the method of stress testing the server, in order to ensure the normal operation of the server.Finally, we introduced the server-side flow control, through configuring different server-side setting, we can effectively control the speed of the software download such as the Thunder. On the one hand, we save bandwidth, and provide a good network environment for users, on the other hand, we protect the server, and provide safeguards for the server's stable operation .In this paper, we introduce two aspects, one is the server load balancing, the other is TCP flow control, from the real need of the system development, we give the solution method. Because of our own technology are not very well, in many places we have many shortcomings. So we should have a improve in the future work and study, and provide users with a stable and efficient document management systems.