What occurs when a switch is flooded with random MAC addresses, causing a MAC address overflow?

When a switch is flooded with random MAC addresses, it leads to a phenomenon known as a MAC flood. This occurs when the switch's MAC address table, which is designed to store MAC addresses to forward frames appropriately, becomes overwhelmed with unwanted or extraneous entries. As the table fills up, the switch can no longer effectively learn valid MAC addresses, causing it to default into a mode where it forwards frames to all ports rather than to a specific destination. This disruption of the normal operation results in increased network traffic and can dramatically reduce overall network performance, as the switch behaves more like a hub, sending out broadcasts to all devices instead of unicast transmissions to specific devices.

The confusion often arises with terms like network congestion and address saturation; while these are related concepts, they do not specifically describe the process of overwhelming the switch’s MAC address table directly. A port malfunction implies a hardware failure, which is not what happens in the case of a MAC flood. Hence, identifying the phenomenon as a MAC flood accurately captures the specific action that disrupts network functionality in this scenario.