When a switch is powered on, it doesn't know where each end device is located on the network. Managed switches store the MAC addresses of devices in a special location called the CAM table.
To get a better idea of how the MAC addresses are stored within the CAM table, we'll use the following network topology to demonstrate:
At this point, the switch has now been powered on and doesn't know which devices are connected to which interfaces/ports, since the CAM table is empty:
Let's assume PC1 wants to send a message to PC4. PC1 would build an Ethernet frame with its source MAC address as AA-AA, and PC4's MAC address of DD-DD as the destination.
Once sent to the switch, the source MAC address is recorded on Port 1, as follows:
Since the switch doesn't have an entry for PC4 (DD-DD), it would send it out of all ports except Port 1 (as that...