A switch learns MAC addresses from the source MAC of incoming frames and uses the CAM table to forward known unicast traffic or flood unknown traffic within the same VLAN.

CAM learning process

1. Receive – the switch receives a frame on a port
2. Learn – reads the source MAC address and stores source MAC → incoming port in the CAM table
3. Lookup – looks up the destination MAC in the CAM table
4. Forward / Flood – destination found → forward only out the correct port; not found → flood to all ports (same VLAN); broadcast/multicast → flood

MAC type	Switch action
Known unicast	Forward
Unknown unicast	Flood
Broadcast	Flood
Multicast	Flood (by default)