For computer network routers, there are different definitions at different stages or from different perspectives. After the completion of ARPANET, the computer network was defined as "a collection of computer systems that are connected by mutual shared resources (hardware, software, and data) and each has independent functions." This definition focuses on the purpose of the application without pointing out the physical structure. When the online terminal network develops into a computer-computer network, in order to distinguish the latter from the former, from the physical structure, the computer router network should be defined as "under the control of the network protocol, by multiple host computers, several terminals, A computer composite system consisting of a data transmission device and a device that communicates between the computer and the computer."
Some router experts in China define a computer network as a system that uses a variety of communication means to organically interconnect geographically dispersed computers to achieve communication and share resources such as software, hardware, and data.