A computer network , or data network , is a digital telecommunications network which allows nodes to share resources. In computer networks, computing devices exchange data with each other using connections between nodes ( data links .) These data links are established over cable media such as wires or optic cables, or wireless media such as WiFi . Network computer devices that originate, route and terminate the data are called network nodes. [1] Nodes can include hosts such as personal computers , phones , servers as well as networking hardware . 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, application-specific communications protocols are layered (i.e. carried as paylo...