The Design And Realization Of The Multicast Of The Large Capacity File In The Network

With the high development of Internet, more and more projects are used in Internet to complete.Used to some applicatcion,such as distributed database development,a developing work group have a lot of people to cooperate and exchange the situation often in different places.In a situation that the scale of the group is smaller,it only needs to exchange information point-to-point;If the scale of the group is larger,exchanging information point-to-point is all a kind of costly burden,no matter to the network or to the person who sends information.Although they are dealt by means of broadcasting sometimes, broadcasts should be poor efficiency even impossible in the situation that it broadcasts to thousands hosts on the million nodal network.First most machines are not interested in this,causing the information rubbish;The more terrible thing is that although some host computer need these information it can be mistaken that they are not interested in this to leave the information.So one method is needed to let workgroup which the scale is larger and is smaller compared to internet transmit information conveniently, swiftly each other. For this reason, the concept of IP multicast has been put up and taken deep research.In the theory stores,the basic principle of TCP/IP protocol is understood deeply at first,and then the theory of multicast is learnt especially.Later a large number of experiments are carried on to the network programming of winsock,which will be the basis of the final realization design,and the design thought of the reliable server have been added among them.At the same time, combining the module design theory of the software engineering, the module overall arrangement has been carried on to the system,and high encapsulation is take to main module,which can be reused in certain degree.In the multicast research of dependability conveyance, especially congested control some new ideas and algorithms have been put forward to design too, which adopt wheel ask and reply way to replying controlling in order of large customer end.Especially the communication technology of multithread is adopted on the control of the end of the server, which has increased the utilization ratio of CPU greatly,and improved replying and reacting efficiency of the server.