What Are the Functions of a Network Bridge?

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network bridge, also known as an Ethernet bridge, connects two segments of a network together. The segments are not independent entities, but are owned and managed by the same organization. The purpose of the bridge is to divide a network into manageable sections.
The Purpose of a Network Bridge

A network bridge connects two networks together, or can be used to divide a network up into segments. Such a bridge forwards incoming data media access control (MAC) addresses, and is often called a "switch" or a "layer 2 switch." Switches are also sometimes referred to as "multi-port bridges."

·  Transparent Bridges

•      When you use a service provider that requires you to configure a specific hardware (MAC) address on your network adapter to connect to the Internet, you use a bridge without being aware of it. This bridge gives you access to the Internet shared with other computers in the local network of your service provider, turning it into more like a traditional network than a sophisticated service provider network. Each computer uses its own MAC to identify itself and the service provider’s router gives an IP address for each MAC address it finds.

Source Route Bridges

•      Source route bridges control token ring networks, where data forwards to every computer in the “ring” until it reaches its destination. Upon reaching it, the destination computer sends back information to the source computer and “frees” the token, giving the other computers a chance to send data. This happens very quickly, and a source route bridge controls the entire scenario, sending packets of data with the full path they will take in their headers.

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Translational Bridges

•      These bridges aid the transition of token ring packets into a traditionally routed Ethernet network. The bridge acts as one of the computers so it doesn’t “talk out of turn” and forwards any data it receives to the Ethernet network for processing by a router. The bridge usually acts also as the router, reducing the amount of devices necessary to complete a task and making the transfer between networks more efficient. Each packet routes to an IP address.

Software ICS Bridges

•      Internet Connection Sharing comes as a feature of Windows from its XP version and onto newer versions of the operating system. This can be done by bridging two Ethernet connections tied to the computer’s network interfaces, making the computer into a sort of pseudo-router. The only disadvantage is that the computer hosting the bridge must be on continuously to act as the bridge. Otherwise, the Internet connection remains idle and no other computers can use the connection.

·  What Does a Network Bridge Do?

•      Network bridges connect two different segments of a network together.

Bridges Vs. Repeaters

•      While bridges and repeaters look alike and perform a similar function, a bridge uses MAC addresses to route data to the appropriate network. A repeater does not employ data filtering and passes all data to every connected network.

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Bridges Vs. Hubs

•      Hubs perform a similar function to bridges in that they route network data. However, hubs can only route network traffic using the same protocol as the hub is programmed to use. Bridges are protocol independent and are often used to connect network segments that use different protocols.

•            The Advantages of a Network Bridge

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. lA 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.

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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.