What Is A Network Bridge?

Date First Published: 12th June 2022

Topic: Computer Networking

Subtopic: Network Hardware

Article Type: Computer Terms & Definitions

Difficulty Level: 6/10

Learn more about what a network bridge is in this article.

A network bridge is a device that can join two separate networks into a single network and act as a 'bridge' between them. Bridges extend LANs to cover a larger area than the LAN can reach and provide communication between the nodes in them. They are less complex and different from routers as they do not analyse or reroute the data being forwarded. Bridging occurs at the data link layer of the OSI model.

Types Of Bridges

Wireless Bridging

Wireless bridging is commonly used on a Wi-Fi network. It is where a wireless bridge joins two separate networks together through radio signals. Two access points that support wireless bridging mode work as a pair. Wireless bridging mode can be enabled by a physical switch on the device or a configuration setting. Not all access points support wireless bridging.

Transparent Bridging

A transparent bridge is used, which works in a way that is transported to all the nodes of a network. In transparent bridging, incoming network traffic is monitored to identify MAC addresses and MAC addresses are recorded by the transparent bridge in a format that is similar to a routing table. Whenever data is routed towards its location, that information is evaluated by the bridge. Transparent bridges use a transparent bridging algorithm, which has five parts, including learning, flooding, filtering, forwarding, and ageing.

Simple Bridging

In simple bridging, two networks are joined together by usually working transparently and choosing whether to forward traffic from one network to another based on the data frames. As part of forwarding, a store and forward technique is used.

Multiport Bridging

In multiport bridging, multiple networks are joined together by usually working transparently and choosing whether to forward traffic from one network to another based on the data frame. In addition, it is necessary for a multiport bridge to decide where to forward traffic.

Difference Between Bridging and Routing

Bridges are different from repeaters as they do not join two networks together and no traffic filtering takes place in a repeater. Repeaters pass along the traffic that they receive and their main purpose is to regenerate traffic signals in order for one network to cover a long physical distance.