What unique address does a network interface card contain?

A network interface card (NIC) contains a unique identifier known as a MAC (Media Access Control) address. This address is hard-coded into the hardware of the NIC and serves several important functions in networking. Each MAC address is a 48-bit number typically represented in hexadecimal format, ensuring that every device on a local network has a unique identifier. This uniqueness allows devices to communicate efficiently on the same network segment, as switches and routers use these addresses to forward data frames correctly to their intended destinations.

In the context of networking, the MAC address operates at the data link layer (Layer 2) of the OSI model, allowing for direct communication between devices connected to the same local network. It plays a crucial role when devices are connecting to Ethernet networks, Wi-Fi, or other types of local area networks.

Other address types such as IP addresses, routing addresses, and network identifiers serve different purposes. IP addresses enable devices to communicate over broader networks (Layer 3), while routing addresses and network identifiers can refer to various types of addresses used within specific network protocols. However, none of these addresses are unique to the NIC itself in the way that a MAC address is.