Final answer:
When a network switch does not know where to send a frame, it floods the frame out of all ports except the one it was received on. This allows the destination device to be reached, respond, and have its MAC address learned and recorded by the switch for future direct transmission.
Step-by-step explanation:
What Happens When a Network Switch Does Not Know Where to Send a Frame?
When a network switch encounters a frame with a destination MAC address that is not listed in its MAC address table, it will perform a process known as a flood. The switch forwardsthe frame out of all its ports except for the port it received the frame on. This is done with the hope that the device with the corresponding MAC address will be reached on one of those ports. If the destination device responds, the switch will learn its MAC address and the associated port, updating its MAC address table so that future frames destined for this device can be forwarded to the correct port directly.
This behavior is significant in the operation of a switch as it ensures that even when the switch does not immediately know how to handle a frame, it can still attempt to deliver it to its destination. If the destination device is on the network, it will reply, allowing the switch to update its MAC address table, which is crucial for efficient network communication.