What type of address does a switch use to build a MAC address table?

What type of address does a switch use to build a MAC address table?

• A. destination MAC address
• B. source MAC address
• C. IP address
• D. broadcast address

Answer: (B)

A switch builds its MAC address table by learning from the frames it receives, specifically using the source MAC address. When a frame lands on a port, the switch records the originator’s MAC address and the port it came in on. Over time, this creates a mapping of each MAC to a specific switch port, which the switch uses to forward future frames directly to the correct device. The destination MAC address is used to decide where to send a frame, not to learn where a device is located. IP addresses operate at a different layer and aren’t used to populate the MAC table (though IP-to-MAC mappings can be learned separately through ARP). Broadcast frames are flooded to all ports, not used to learn a specific device’s location.

A switch builds its MAC address table by learning from the frames it receives, specifically using the source MAC address. When a frame lands on a port, the switch records the originator’s MAC address and the port it came in on. Over time, this creates a mapping of each MAC to a specific switch port, which the switch uses to forward future frames directly to the correct device. The destination MAC address is used to decide where to send a frame, not to learn where a device is located. IP addresses operate at a different layer and aren’t used to populate the MAC table (though IP-to-MAC mappings can be learned separately through ARP). Broadcast frames are flooded to all ports, not used to learn a specific device’s location.