What data structure on a switch maps MAC addresses to physical ports to enable efficient forwarding decisions?

What data structure on a switch maps MAC addresses to physical ports to enable efficient forwarding decisions?

• A. Routing Table
• B. ARP Cache
• C. MAC Address Table
• D. VLAN Table

Answer: (C)

The switch uses a MAC address table to map MAC addresses to the specific switch ports where devices are connected, enabling fast forwarding decisions. As frames arrive, the switch learns the source MAC address and the ingress port, recording this mapping in the table. When a frame needs to be forwarded, the switch looks up the destination MAC in the table to send the frame out only to the appropriate port. If the destination is unknown, the switch floods the frame to all ports to learn where the device lies. Entries age out if not refreshed, allowing the table to adapt as devices move. This is different from a routing table, which relates to layer 3 paths to destinations; an ARP cache maps IP addresses to MAC addresses for hosts and routers, not for per-switch forwarding decisions; and a VLAN table manages segregated networks, not the per-MAC port mapping used for forwarding.

The switch uses a MAC address table to map MAC addresses to the specific switch ports where devices are connected, enabling fast forwarding decisions. As frames arrive, the switch learns the source MAC address and the ingress port, recording this mapping in the table. When a frame needs to be forwarded, the switch looks up the destination MAC in the table to send the frame out only to the appropriate port. If the destination is unknown, the switch floods the frame to all ports to learn where the device lies. Entries age out if not refreshed, allowing the table to adapt as devices move.

This is different from a routing table, which relates to layer 3 paths to destinations; an ARP cache maps IP addresses to MAC addresses for hosts and routers, not for per-switch forwarding decisions; and a VLAN table manages segregated networks, not the per-MAC port mapping used for forwarding.