(A campus network (COMPUSNETWORK, hereinafter also referred to as a campus network) is a very typical example of a comprehensive network. In order to illustrate the main problem, the design of the actual campus network is appropriately and necessary simplified in this design scheme. At the same time, the focus is on the design of the network backbone, and only a brief introduction is given for the server setup. For the specific content, refer to the relevant reference books.)