A switch floods frames out of all ports when it does not know the destination port.

A switch floods frames out of all ports when it does not know the destination port.

• A. True
• B. False
• C. Only to the uplink port
• D. Only to the source port

Answer: (A)

When a switch handles frames, it builds a MAC address table by learning which port each source MAC is reachable on. If the destination MAC isn’t yet in that table, the switch doesn’t know which port to send the frame to. To ensure delivery and to learn where the destination is, the switch floods the frame out of all ports in the same VLAN (except the port it came from). This flood remains in effect until the destination MAC is learned, after which future frames to that destination are sent only to the specific learned port. This behavior is why the statement is true. Broadcast and multicast frames are typically flooded as well because there isn’t a single destination port to target.

When a switch handles frames, it builds a MAC address table by learning which port each source MAC is reachable on. If the destination MAC isn’t yet in that table, the switch doesn’t know which port to send the frame to. To ensure delivery and to learn where the destination is, the switch floods the frame out of all ports in the same VLAN (except the port it came from). This flood remains in effect until the destination MAC is learned, after which future frames to that destination are sent only to the specific learned port. This behavior is why the statement is true. Broadcast and multicast frames are typically flooded as well because there isn’t a single destination port to target.