Learning MAC Addresses and Frames Flooding

When a switch receives a frame on a port, it reads the source MAC address of the frame and records it in its MAC address table. The MAC address table is a mapping of MAC addresses to the port where the switch learned that address. This process is known as “learning” and it allows the switch to forward frames only to the ports where the destination MAC address is located.

If the switch does not know the destination MAC address in its MAC address table, it floods the frame to all ports except the one where the frame was received. This is called “flooding.” Flooding is used to ensure that the frame reaches its destination, even if the switch does not know where the destination MAC address is located.

When a switch receives a frame with a destination MAC address that it knows, it forwards the frame only to the port where the destination MAC address is located. This is called “forwarding.”

If the switch receives a frame with a destination MAC address that is not in its MAC address table, it floods the frame to all ports except the one where the frame was received. However, once the switch learns the location of the destination MAC address, it will update its MAC address table and forward subsequent frames destined for that address only to the appropriate port.