A network bridge, or a layer 2 switch, connects two different local area networks (LAN) or segments of the same LAN. A bridge is used to segregate data by dividing it into two streams. This way it effectively reduces the traffic flow over a LAN. A bridge operates by determining whether incoming data (or traffic) is to be routed to a forwarding address or discarded. Packets of data received by the bridge carry the destination address, which is read by the bridge and deciphered accordingly. The three major types of network bridges include local bridges (to connect LANs), remote bridges (to connect LANs with a wide area network or a WAN) and wireless bridges (to connect remote networks with LANs).
Prevents Bandwidth Waste
A bridge managed incoming traffic and reduces bandwidth waste by preventing all unnecessary flow of data between network segments. This way it can effectively ensure the optimal performance on both sides of the network segment. A bridge can be thought of as the traffic police, controlling the flow of legitimate data and disallowing all unnecessary traffic through. Bandwidth waste creates unnecessary delays and slows down the performance of the network. A bridge therefore behaves as a bandwidth monitor, channeling relevant data and discarding scrap to increase bandwidth throughput. It can be thought of as a traffic shaping/managing firewall.
Increases Network Length
A network bridge increases the functional length of a network by connecting individual LAN segments. Networks can be segmented and brought together without the need to create IP subnets or using a router. A network bridge increases the size of the network without the need for hardware equipment such as cables, and software constraints such as firewalls.
Links Dissimilar Network Transmission Segments
A bridge can connect both similar and dissimilar LAN segments. It can connect, for instance, an Ethernet segment with a Token Ring segment, allowing both to behave as one and have the same IP address. A bridge connects LAN segments with different protocols, a LAN segment with the Internet and a wireless local area network (WLAN) with a LAN segment. A bridge is also used to connect two CSMA/ CD LANs, and a token ring LAN with a CSMA/ CD LAN. It is necessary to connect dissimilar segments possessing different protocols for data transmission.