CCNA: Cisco Certified Network Associate — Question 1230

What does a switch do when it receives a frame whose destination MAC address is missing from the MAC address table?

Answer options

• A. It changes the checksum of the frame to a value that indicates an invalid frame.
• B. It updates the CAM table with the destination MAC address of the frame.
• C. It appends the table with a static entry for the MAC and shuts down the port.
• D. It floods the frame unchanged across all remaining ports in the incoming VLAN.

Correct answer: D

Explanation

The correct answer is D because when a switch does not find the destination MAC address in its MAC address table, it floods the frame to ensure it reaches its intended recipient. Option A is incorrect as the checksum is not modified; option B is misleading since the switch does not add the address until after flooding; option C is incorrect because the switch does not create static entries or shut down ports in this scenario.