Network bridging describes the action taken by network equipment to allow two or more communication networks, or two or more network segments, to create an aggregate network. Bridging is distinct from routing which allows the networks to communicate independently as separate networks. A network bridge is a network device that connects more than one network segment. In the OSI model bridging acts in the first two layers, below the network layer.
There are four types of network-bridging technologies: simple bridging; multiport bridging; learning, or transparent bridging; and source route bridging. Transparent bridging was originally developed by the Digital Equipment Corporation (DEC) in the 1980s.
See also 
- Audio Video Bridging
- Collision domain
- IEEE 802.1D
- Instrument bridge
- Laser bridge
- Promiscuous mode
- Shortest Path Bridging
- Spanning Tree Protocol
- Wireless bridge
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- "Transparent Bridging". Cisco Systems. Retrieved 2010-06-20.