What happens when a switch receives a frame with a destination MAC address that does not match any of its entries?

When a switch receives a frame with a destination MAC address that is not found in its MAC address table, it cannot determine the specific port to send the frame to. In this case, the switch uses a process called flooding. This involves broadcasting the frame out on all ports except for the port where the frame originated. This approach allows the switch to reach the intended recipient, assuming that the device with the specified MAC address is located on one of the other ports.

This behavior is fundamental to the operation of Ethernet switches, ensuring that frames can still reach their intended destination even if the switch has not yet learned the MAC address of that destination device. As devices communicate and the switch continues to receive traffic, it will eventually learn the MAC addresses of connected devices and their corresponding ports, which will reduce the need for broadcasting over time.

The options related to dropping the frame or forwarding it to a default gateway do not accurately capture how switches handle this situation. Queuing the frame for processing also does not align with the switch's logic for forwarding frames. Instead, broadcasting allows for the dynamic learning of MAC addresses within the switching network.