A device that connects networks by using the same communications protocols so that information can be passed from one to the other. Also, a device that connects two local area networks, whether or not they use the same protocols. A bridge operates at the ISO/OSI data-link layer.
A network bridge connects multiple network segments at the data link layer (layer 2) of the OSI model. Bridges are similar to repeaters or network hubs, devices that connect network segments at the physical layer, however a bridge works by using bridging where traffic from one network is managed rather than simply rebroadcast to adjacent network segments. In Ethernet networks, the term "bridge" formally means a device that behaves according to the IEEE 802.1 D standard - this is most often referred to as a network switch in marketing literature.