The unmanaged switch is the data link layer device. It can identify the MAC address information in the data packet, then forward it according to the MAC address, and record these MAC addresses and corresponding ports in an internal address table of its own. When a device sends a packet to another device, it enters the switch and the switch reads its header to determine what to do with it. It matches the destination address or addresses and sends the packet out through the appropriate ports that leads to the destination devices.