|  | 8.3 | The Data Link Layer
| 8.3.3 | The function and characteristics of MAC addresses

A MAC address is a unique address burned onto the memory of a network interface card (NIC). Ethernet requires each computer to have a MAC address, and any computer with a MAC address is called a node. MAC addresses use a 48-bit address, which is a unique identifier for each device and is used for delivering data to a specific location. MAC addresses (layer 2 addresses, hardware addresses, physical addresses) are crucial to the functioning of LANs, allowing local delivery of frames and packets. A MAC address is similar to a social security number or personal identification number.