Network bridging takes place at layer 2 (the data link layer) of the OSI model. There are several different types of bridges. A simple bridge isn't much different from a repeater, except for the fact that the two network segments it connects may use different types of media (for example, one segment may use 100Base-T cabling and the other may use 1000Base-T) and the fact that bridges use a store-and-forward mechanism to forward packets, thus creating two separate collision domains.
A simple bridge forwards packets to the other side of the bridge, regardless of whether the destination host is on the other side. There are bridges known as transparent bridges, however, which are able to learn which side of the bridge hosts are on and ...
