What does bridging mean?
Bridging refers to the process of forwarding network packets according to the address of the link layer of the OSI network model, which works on the second layer of OSI. In general switches, bridges act as bridges.
If a frame is added to an interface, an entry will be inserted into a bridge, listing the MAC addresses of the host that sends data and the interface that receives the data frame, so that the routing table will be continuously improved in communication. Transparent bridging makes the router transparent to the host, which is equivalent to a LAN switch. If two hosts in the same LAN communicate, the data frames will not be sent to other interfaces, because in the bridge table, the data frames come from the same interface; if a frame is received, and the MAC address is not in the bridge table, the frame will be spread to all interfaces, and the bridge will spread to all interfaces. Broadcast packets occupy the effective bandwidth of the network, causing network congestion. We know that Cisco IOS supports many types of bridges, such as transparent bridging, encapsulated bridging, source routing bridging, source routing transparent bridging, source routing conversion bridging.