Switch Address Learning

The switch has no knowledge about the network and don't know which devices connected to them.

They learn the device locations by examining incoming frames and recording the mac address in the MAC address table.

For example: here, since Host B wants to send package to Host A. The switch look up the MAC address table to see where host A is.

Note: initially, the switch doesn't have Host A and Host B in the table. Therefore it will perform Flood to be able to know where the destination is.