Bridge

1) A bridge is a device that connects two or more local area networks, or two or more segments of the same network.

2) The original bridges were typically 2 or more ports (low port counts) and could separate MAC addresses using the table for those ports.

3) In the OSI model bridging acts in the first two layers, below the network layer.


Q: How to make a bridge table?
A:

Ref.:
http://en.wikipedia.org/wiki/Bridging_(networking)
http://www.definethecloud.net/data-center-101-local-area-network-switching/
http://technet.microsoft.com/en-us/library/cc700841.aspx