What does a switch learn when it stores a device's MAC address in its MAC address table?

What does a switch learn when it stores a device's MAC address in its MAC address table?

• A. IP address associated with a device
• B. Device host name
• C. MAC addresses identify devices on the local area network
• D. VLAN assignment

Answer: (C)

Switches learn which device is reachable on which port by recording the device’s MAC address in the MAC address table. When a frame arrives, the switch notes the source MAC and the port it came from, building a map of MAC addresses to switch ports. This lets the switch forward future frames directly to the correct port without broadcasting to everyone. The MAC address is the hardware identifier used on the local network, so storing it in the table identifies devices on the LAN and tells the switch where to send frames destined for them. Each VLAN has its own set of MAC-address mappings, so the learning happens per VLAN. The other options aren’t what the MAC table stores: IP addresses are layer 3 identifiers learned by routers or layer-3 switches, hostnames aren’t used by switches for forwarding, and VLAN assignment is about segmentation rather than being the content of the MAC table itself.

Switches learn which device is reachable on which port by recording the device’s MAC address in the MAC address table. When a frame arrives, the switch notes the source MAC and the port it came from, building a map of MAC addresses to switch ports. This lets the switch forward future frames directly to the correct port without broadcasting to everyone. The MAC address is the hardware identifier used on the local network, so storing it in the table identifies devices on the LAN and tells the switch where to send frames destined for them. Each VLAN has its own set of MAC-address mappings, so the learning happens per VLAN. The other options aren’t what the MAC table stores: IP addresses are layer 3 identifiers learned by routers or layer-3 switches, hostnames aren’t used by switches for forwarding, and VLAN assignment is about segmentation rather than being the content of the MAC table itself.