Computer networking is the engineering discipline concerned with communication between computer systems or devices. Networking, routers, routing protocols, and networking over the public Internet have their specifications defined in documents called RFCs. Computer networking is sometimes considered a sub-discipline of telecommunications, computer science, information technology and/or computer engineering. Computer networks rely heavily upon the theoretical and practical application of these scientific and engineering disciplines.

A computer network is any set of computers or devices connected to each other with the ability to exchange data. Examples of networks are:

• local area network (LAN), which is usually a small network constrained to a small geographic area.
• wide area network (WAN) that is usually a larger network that covers a large geographic area.
• wireless LANs and WANs (WLAN & WWAN) is the wireless equivalent of the LAN and WAN

All networks are interconnected to allow communication with a variety of different kinds of media, which including twisted-pair copper wire cable, coaxial cable, optical fiber, and various wireless technologies. The devices can be separated by a few meters (e.g. via Bluetooth) or nearly unlimited distances (e.g. via the interconnections of the Internet ).