Network is made up of nodes and connections, said a number of objects and their interlinkages. In mathematics, the network is a graph is generally believed to refer to the weighted graph. Outside of mathematical definitions, network, as well as specific physical meaning, which is the one real issue abstract models of the same type. In the field of computers, the network is the virtual platform of information transfer, receive, share, through its contact point, area and volume of information together, so as to realize the sharing of these resources. Networking is the most important inventions in human history, improved technology and the development of human society.