15        Next Page
   14        Ack
   13        Remote Fault
   12        Reserved
 11         Asymmetric Pause
 10         Pause
 9          100BASE-T4
8 100BASE-TX Full-duplex
7 100BASE-TX Half-duplex
6 10BASE-TX Full-duplex
 5          10BASE-TX Half-duplex
 4:0        Selector Field