Networking is the connecting of computers to share data (e.g., files and databases) or functionality (e.g., printers, scanners, Internet connections, etc).

A network can be as small as a local area network (LAN), where two computers share information using a hub or switch, or as big as a wide area network (WAN), where many libraries in different locations share an Internet connection or automated library system.

The way machines are connected has changed over the years, but at the building level, the most common technologies right now are Ethernet and 802.11b (i.e., wireless or Wi­Fi), or a combination of the two. Between buildings, at the WAN level, organizations use a wide variety of equipment and protocols (e.g., Frame Relay, T-­1, Ethernet, Asynchronous Transfer Mode (ATM) and various fiber protocols).