Based On The Expansion Of The Resource Sharing System With A String Loop Design And Realization

With the Internet stretches everywhere in our daily life, far-sight scholars and corporations recovered the huge potential computing power hiding in the net nodes. So the distributed application based on Internet becomes hot subject, and the success of P2P software demonstrates it. At the same time, traditional softwares turning to Internet services, the .NET and Live.com strategies by Microsoft, and cloud computing by Google, express the new trend. In this thesis, it's abstracted as resources which can be shared by Internet, and it could be a piece of data, a file, or a kind of services.This thesis describes a method to construct a resource sharing system. The system regards information and services as a kind of resources, namely, the descriptions of information and services are consistent, all by resource description block. Users of this system can register and search resources through GUI and other interface. Firstly, we analyse the technical details to cross NAT. Because of insufficent IP address and the existence of firewall, most users in China are behind NAT, that obstacles their directly communications. Crossing NAT is necessary for diging the potentials of user nodes. Then, we share the ideas of deploying system, the topology and the routing principle. After that, we discuss the implement of this system, including cross-platform libary wxWidgets, network message processing, node state transforming, node detecting and etc. Finally, we analyse the system performance and conclude.It's extended chord ring topology that be employed by the resource sharing system. For not suitbale to orgnize the dynamic nodes changing frequently, in this system, chord ring connects top-level server nodes, providing high routing efficiency and fault tolerence capability. To facilitate user resource registering and monitoring, every user-end deploys a daemon. These daemones form a 3-level tree topology, local server as its root, to realize the high scalability with the tree's feature. This system updates the route table refresh mechanism: if server nodes keep stable, the route table will degenerate as a hash table, so the routing efficiency goes better. And the common node in this system doesn't always connect a fixed uplink node, the self-adaptive uplink mechanism can avoid unstables caused by uplink node crash.