What is the primary function of the CAM table in a switch?

What is the primary function of the CAM table in a switch?

• A. To map IP addresses to switch ports
• B. To cache DNS mappings
• C. To map MAC addresses to the corresponding switch ports
• D. To store MAC addresses for port forwarding

Answer: (C)

The CAM table in a switch stores mappings of MAC addresses to the switch ports they’re reachable on. As frames arrive, the switch records the source MAC address and the port it came from, building a live table of where each device is located on the network. When a frame needs to be forwarded, the switch looks up the destination MAC in this table and sends the frame only out the corresponding port, which makes forwarding efficient. If the destination MAC isn’t yet known, the switch floods the frame to all ports to learn where that device is. Entries age out over time so the table stays current as devices move. This behavior is specific to Layer 2 switching and MAC addresses; IP-to-port mappings or DNS caches live in other parts of the network stack, and describing the CAM as storing MACs for port forwarding is imprecise.

The CAM table in a switch stores mappings of MAC addresses to the switch ports they’re reachable on. As frames arrive, the switch records the source MAC address and the port it came from, building a live table of where each device is located on the network. When a frame needs to be forwarded, the switch looks up the destination MAC in this table and sends the frame only out the corresponding port, which makes forwarding efficient. If the destination MAC isn’t yet known, the switch floods the frame to all ports to learn where that device is. Entries age out over time so the table stays current as devices move. This behavior is specific to Layer 2 switching and MAC addresses; IP-to-port mappings or DNS caches live in other parts of the network stack, and describing the CAM as storing MACs for port forwarding is imprecise.