A network bridge connects two separate computer networks. The network bridge enables communication between the two networks and provides a way for them to function as a single network. Bridges extend local area networks to cover a larger physical area than the LAN can reach. Bridges are similar to — but more intelligent than — simple repeaters, which also extend signal range.

Bridge devices inspect incoming network traffic and determine whether to forward or discard the traffic based on its intended destination. For example, an Ethernet bridge inspects each incoming Ethernet frame, including the source and destination MAC addresses—and sometimes the frame size—as it processes individual forwarding decisions. Bridge devices operate at the data link layer of the OSI model.

Bridge devices support Wi-Fi to Wi-Fi, Wi-Fi to Ethernet, and Bluetooth to Wi-Fi connections. Each is designed for a specific type of network.

Bridging is popular on Wi-Fi computer networks. On a Wi-Fi network, wireless bridging requires access points to communicate with each other in a special mode that supports the traffic flowing between them.