Which statement best describes a MAC address table?

Which statement best describes a MAC address table?

• A. It maps MAC addresses to switch ports to forward frames.
• B. It maps IP addresses to MAC addresses.
• C. It stores routing information for IPv6.
• D. It resolves domain names to IPs.

Answer: (A)

A MAC address table is used by switches to map a device’s MAC address to the switch port through which that device can be reached, enabling efficient frame forwarding. The switch learns this by observing the source MAC address on frames as they arrive on a particular port, associating that MAC with that ingress port. When a frame needs to be sent, the switch looks up the destination MAC in the table and forwards the frame only on the corresponding port; if the destination MAC isn’t known yet, the switch floods the frame to all ports in the same layer-2 domain until it learns the mapping. This behavior is what allows a switch to move traffic quickly and correctly without consulting higher-layer information. It’s not about mapping IP addresses to MACs—that function belongs to ARP—nor about storing IPv6 routing information, nor about resolving domain names to IPs (DNS).

A MAC address table is used by switches to map a device’s MAC address to the switch port through which that device can be reached, enabling efficient frame forwarding. The switch learns this by observing the source MAC address on frames as they arrive on a particular port, associating that MAC with that ingress port. When a frame needs to be sent, the switch looks up the destination MAC in the table and forwards the frame only on the corresponding port; if the destination MAC isn’t known yet, the switch floods the frame to all ports in the same layer-2 domain until it learns the mapping. This behavior is what allows a switch to move traffic quickly and correctly without consulting higher-layer information. It’s not about mapping IP addresses to MACs—that function belongs to ARP—nor about storing IPv6 routing information, nor about resolving domain names to IPs (DNS).