Cisco
200-301 · Question #411
Why does a switch flood a frame to all ports?
The correct answer is D. The destination MAC address of the frame is unknown.. Switches tend to flood frame with the Unknown Destination MAC Address out all ports apart from the Originating (apart from the one it received) port.
Submitted by krish.m· Mar 5, 2026Network Access
Question
Why does a switch flood a frame to all ports?
Options
- AThe frame has zero destination MAC addresses.
- BThe source MAC address of the frame is unknown
- CThe source and destination MAC addresses of the frame are the same
- DThe destination MAC address of the frame is unknown.
How the community answered
(39 responses)- A3% (1)
- B5% (2)
- D92% (36)
Explanation
Switches tend to flood frame with the Unknown Destination MAC Address out all ports apart from the Originating (apart from the one it received) port.
Topics
#Switch forwarding#MAC address table#Unknown unicast flooding#Ethernet switching
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