The Research Of A Ftp-like File Transmission Sharing System

In this thesis, we propose a new ftp-like file transmission sharing system that takes into account the advantages of ftp and p2p, especially BitTorrent mode, to reduce client download time and server load when clients download large, popular files. This thesis starts with the introduction of the ftp network structure based on the traditional client/server mode. Later BitTorrent, the most popular file-sharing platform, is analyzed in detail. And then we deeply examine two general aspects of p2p architectures, according to which the p2p systems can be differentiated and categorized: the degree of centralization, and the network structure. After analyzing the structure of above-mentioned systems, this thesis provides a detailed design of this ftp-like file transmission sharing structure. This structure consists of three parts: one master file server, one authentication and topology server (ATS) and client nodes. The file server offers file resources to clients. ATS is responsible for authenticating clients, choosing super-nodes and providing clients with topology services. This structure divides the client nodes into super-nodes and ordinary nodes。Super-nodes are divided into master super-nodes and alternative super-nodes. Master super-nodes serve as the server of file cache agent and implement the file-downloading request of ordinary clients for master file server. Thus, the load of master file server can be reduced. Alternative super-nodes are used to support underlying p2p network. Finally, this thesis gives the modeling and simulation of this file transmission sharing structure. The results indicate that the ftp-like file transmission sharing structure can effectively reduce client download time and server load. Moreover, this thesis put forward some suggestions and prospect according to this structure.