A computer network is a digital telecommunications network which allows nodes to share resources. In computer networks, computing devices exchange data with each other using connections ( data links ) between nodes. These data links are established over cable media such as wires or optic cables, or wireless media such as Wi-Fi . Network computer devices that originate, route and terminate the data are called network nodes. [1] Nodes are generally identified by network addresses , and can include hosts such as personal computers , phones , and servers , as well as networking hardware such as routers and switches. Two such devices can be said to be networked together when one device is able to exchange information with the other device, whether or not they have a direct connection to each other. In most cases, a...