Default Behavior of a Layer 2 Switch

C

If the destination MAC address is not in the CAM table (unknown destination MAC address), the switch sends the frame out all other ports that are in the same

VLAN as the received frame. This is called flooding. It does not flood the frame out the same port on which the frame was received.

When a Layer 2 switch receives a frame with an unknown destination MAC address, its default behavior is to flood the frame to all ports except the port on which it was received within the same VLAN. This is done in an attempt to reach the correct destination.

Option A is not correct because the switch does not add the unknown destination MAC address to its MAC address table. The switch only learns the MAC addresses of the devices connected to its ports when frames are sent from those devices.

Option B is not correct because the switch does not send a copy of the packet to the CPU for destination MAC address learning. The switch only learns the MAC addresses of the devices connected to its ports when frames are sent from those devices.

Option C is the correct answer because flooding packets to all ports except the receiving port within the same VLAN is the default behavior of a Layer 2 switch when an unknown destination MAC address is received. However, flooding can cause unnecessary traffic and increase network congestion.

Option D is not correct because the switch does not drop the received frame by default. Instead, it floods the frame to all ports within the same VLAN except the port on which the frame was received.