How do switches manage traffic directed to unknown destination MAC addresses?

When a switch encounters traffic directed to an unknown destination MAC address, it employs a method known as flooding. This means that the switch broadcasts the traffic to all ports on the switch, except for the port from which the traffic originated. The primary reason for this approach is to ensure that the frame reaches its intended destination, even if the switch does not yet have a record of the destination MAC address in its MAC address table.

Flooding is essential for maintaining network communication especially in scenarios where a device is new to the network or has just been powered on, and thus its MAC address is not yet learned by the switch. Once the intended device receives the frame, it will respond, allowing the switch to learn the MAC address and associate it with the appropriate port for future communications. This enables the switch to handle traffic more efficiently over time by reducing the need to flood traffic for known destinations.