What is the function of a switch's MAC address table?

The function of a switch's MAC address table is to map MAC addresses to specific switch ports for frame forwarding. When a switch receives a data frame, it reads the source MAC address of the frame and records it in its MAC address table along with the port it came from. This allows the switch to build a record of which devices (identified by their MAC addresses) are connected to which ports.

When the switch needs to forward a frame destined for a specific MAC address, it consults its MAC address table to determine the correct port to send the frame out of, thereby improving network efficiency and reducing unnecessary traffic. This functionality is crucial for the proper operation of Ethernet networks, as it allows for the seamless communication between devices without needing to broadcast every frame to all ports.