From the bridge-utils homepage:

A bridge is a way to connect two Ethernet segments together in

a protocol independent way. Packets are forwarded based on

Ethernet address, rather than IP address (like a router). Since

forwarding is done at Layer 2, all protocols can go

transparently through a bridge.



The Linux bridge code implements a subset of the ANSI/IEEE

802.1d standard. [1]. The original Linux bridging was first

done in Linux 2.2, then rewritten by Lennert Buytenhek. The

code for bridging has been integrated into 2.4 and 2.6 kernel

series.-From the bridge-utils homepage:

　　　　A bridge is a way to connect two Ethernet segments together in

　　　　a protocol independent way. Packets are forwarded based on

　　　　Ethernet address, rather than IP address (like a router). Since

　　　　forwarding is done at Layer 2, all protocols can go

　　　　transparently through a bridge.



　　　　The Linux bridge code implements a subset of the ANSI/IEEE

　　　　802.1d standard. [1]. The original Linux bridging was first

　　　　done in Linux 2.2, then rewritten by Lennert Buytenhek. The

　　　　code for bridging has been integrated into 2.4 and 2.6 kernel

　　　　series.