Network PC World

The term bridging refers to a technology in which a device known as a bridge connects two or more LAN segments. Bridges are OSI Data Link layer, or Layer 2, devices that were originally designed to connect two network segments. Multiport bridges were introduced later to connect more than two network segments, these devices analyze the frames as they come in and make forwarding decisions based on information in the frames themselves. Bridges learn the location of the network stations without any intervention from a network administrator or any manual configuration of the bridge software. This process is commonly referred to as self−learning. When a bridge is turned on and begins to operate, it examines the MAC addresses located in the headers of frames passed through the network. As the traffic passes through the bridge, the bridge builds a table of known source addresses, assuming the port from which the bridge received the frame is the port to which the device is a sending device