This object determines which AutoNegAd bits may be changed by
the user. Bits set to 1 indicate user may choose whether to
advertise the corresponding capability. Bits are cleared if
user is not allowed to change the corresponding AutoNegAd bit.
Capability Bit
---------------------- ---
reserved 0
Flow Control 1
1000 Mbps Full Duplex 2
1000 Mbps Half Duplex 3
100 Mbps Full Duplex 4
100 Mbps Half Duplex 5
10 Mbps Full Duplex 6
10 Mbps Half Duplex 7
OCTET STRING bitmasks count the leftmost bit (MSB) as 0.