Design And Implementation Of Source-Driving File Distribution System Based On Overlay Network

With the development of computer technology, the file magnitude becomes more and more large, which increases from MB to TB. There is ever high requirement for reliable file distribution to designate receivers, especially for government institutions and large organizations like corporations. P2P is a mature solution to solve problems of downloading large files. However, the current P2P system is driven by the file receiver, and file source cannot specify files receiver. Therefore, the P2P cannot achieve directional file distribution. Moreover, in the P2P system, due to the AS topology and ISP business relationships are not considered by the connection between Peers, resulting in a greater inter-domain traffic overhead, which makes P2P model resisted by the ISP. Thus the development and application of P2P technology was limited.Aiming at the security problem of large-scale file distribution, the paper design and realize a source-driving file distribution system (SDFD) based on overlay network.First, aiming at the problem that P2P has spent excessive inter-domain traffic, by studying the strategy of overlay deployment and P2P file exchange, we propose system architecture combine P2P and the application layer multicast to confine P2P file distribution domain and thus reduce the inter-domain traffic.Second, to meet the needs that receivers can be designated by source, SDFD system transfer the sponsor from receivers to data source, which can designate receivers. Receivers change their role from positive searching to objective receiving. Once receiver received order, client will automatically download the file. Furthermore, we can rate the user and content to strengthen the security.Third, aiming at the demand for reliable file distribution, by disposing the overlay-nodes in P2P networks, we supply the cache service for file distribution. Even if data source are offline, client can get data from overlay-nodes, thus solve the problem of torrent file invalidation.Fourth, there are a large number of studies on the application layer multicast, but few focus on the structure of AS domains. We propose an application layer multicast tree generation algorithm for"valley-free" and "prefer-customer" rules.In this paper, we design a system communication protocol. We also introduce the workflow of authenticate, file upload, torrent file distribute and file distribute. Furthermore, we design the software module of management server, overlay-node and client.We test the SDFD system on linux platform. The results show that SDFD system can supply oriented file distribute, controllable meeting and cache service. It apparently reduces inter-domain traffic. While the data source is offline, client can get data from overlay-nodes, thus ensure that the file offline transmission and solve the problem of torrent file invalidation. Furthermore, with the addition of overlay-nodes, Our design runs faster than normal P2P system.