What is the effect of flooding a switch's CAM table with random MAC addresses?

• A. It forwards frames only to the destination port
• B. It stops forwarding frames entirely
• C. It broadcasts frames to all ports
• D. It automatically updates the CAM table

Answer: (C)

Switch forwarding relies on a CAM table that maps MAC addresses to the specific ports where devices reside. When a frame arrives, the switch looks up the destination MAC. If there’s a matching entry, the frame is sent only to that port. If not, the switch doesn’t know where to send it, so it floods the frame out of all ports in the same VLAN (except the one it came from) to ensure delivery and to learn the destination's location.

Flooding the CAM with random MAC addresses fills the table with bogus, non-existent mappings, so real traffic often appears as unknown destinations. As a result, frames are broadcast to all ports rather than being unicast to a single destination. This is why MAC flooding leads to widespread broadcasting and degraded performance. It does not automatically update the CAM with correct mappings, and it doesn’t stop forwarding or route to only a specific port.