48/64 bit 之 MAC 地址

http://www.dimensional.com/findmac.html
Finding your MAC address 

Windows 
        Windows 95/98 
        Windows NT 
    Macintosh 
        With Open Transport (Includes Mac OS 8+) 
        With MacTCP 
    Unix 
        Solaris/SunOS 
        Linux 
        FreeBSD 
        HP-UX 

To support encapsulation of EUI-48 values within a small subset of the EUI-64 values, the first four digits of the
manufacturer's extension identifier shall not be FFFF16 or FFFE16. Thus, the 64-bit values of the following form
(where 'x' is a arbitrary hexadecimal digit) are never-assigned EUI-64 values:

   ccccccFFFEeeeeee16   (an EUI-48 extension)

  xxxxxxFFFFxxxxxx16  (reserved by IEEE/RAC)

The letters 'c' and 'e' represent hexadecimal digits and show how the EUI-48 value can be unambiguously
encapsulated within the EUI-64 value; the 'c' and 'e' digits represent the company_id and extension-identifier
portions of the EUI-48 value respectively.