A media access control address is a unique 48-bit identifier assigned to a network interface controller. It is used on data link layer (layer 2 of OSI model) of computer networking as a network address. MAC addresses are assigned by device manufacturers and usually includes manufacturer's 24-bit OUI (Organizationally Unique Identifier). Now they refers as EUI-48 identifiers.
48-bit address MAC address starts with 24-bit OUI, 28-bit OUI-28/MA-M or 36-bit OUI-36/MA-S identification numbers. IEEE 802 standard format for printing Extended Unique Identifiers (EUI-48) is six groups of two hexadecimal digits separated by hyphens.
IEEE is the world's largest technical professional organization dedicated to advancing technology for the benefit of humanity. IEEE Registration Authority deals with assigning unique identifiers to manufacturers. Obtaining registered identifiers is payable and cost depends on below block size: