The Media Access Control (MAC) address is a binary number used to identify computer network adapters. These numbers (sometimes called hardware addresses or physical addresses) are embedded in the networking hardware during the manufacturing process or stored in firmware and are designed not to be changed.
Obtaining a link-local EUI 64 from a MAC address
Traditional MAC addresses are 12-digit (6 bytes or 48 bits) hexadecimal numbers. By convention, these addresses are usually written in one of three formats, although there are variations:
The leftmost six digits (24 bits), called a prefix, are associated with the adapter manufacturer (M). Each vendor registers and obtains MAC prefixes as assigned by the IEEE. Vendors often have many prefix numbers associated with their products. For example, the prefixes 00:13:10, 00:25:9C, and 68:7F:74 (plus others) belong to Linksys (Cisco Systems).
The rightmost digits of a MAC address represent an identification number for the specific device (S). For all devices manufactured with the same vendor prefix, each device is given a unique 24-bit number. Hardware from different vendors can share the same device portion of the address.
