In a switch, what is stored to map a MAC address to its location on the switch?

• A. Map IP addresses to MAC addresses
• B. MAC addresses to switch port locations
• C. Routing paths to networks
• D. DHCP assignments

Answer: (B)

A switch keeps a MAC address table that maps each observed MAC address to the switch port (and VLAN) where that device can be reached. When a frame arrives, the switch records the source MAC and the ingress port, creating or updating the entry so future frames destined for that MAC can be sent only out the correct port. This MAC-to-port mapping is what allows the switch to forward traffic efficiently and avoid flooding unneeded ports. If the destination MAC isn’t in the table yet, the switch floods the frame to all ports in the same VLAN, learning the location as responses come back. Entries age out if the device stops talking, so the table stays current. The other options aren’t right because IP-to-MAC mappings are handled by ARP, routing paths are stored in routing tables on routers, and DHCP assignments relate to IP addresses rather than mapping hardware addresses to switch locations.