MAC Address - Network Encyclopedia
Definition of MAC Address.
MAC - Media Access Control
MAC Address is a unique 6-byte (48-bit) address that is usually permanently burned into a network interface card (NIC) or other physical-layer networking device and that uniquely identifies the device on an Ethernet-based network.
The uniqueness of MAC addresses is ensured by the Institute of Electrical and Electronics Engineers (IEEE), which assigns networking device vendors specific blocks of MAC addresses for the devices they produce. The first 3 bytes (24 bits) represent the manufacturer of the card, and the last 3 bytes (24 bits) identify the particular card from that manufacturer.