A count of MAC Control frames received on this
interface that contain an opcode that is not
supported by this device.
This counter is a 64 bit version of
dot3ControlInUnknownOpcodes. It should be used
on interfaces operating at 10 Gb/s or faster.
Discontinuities in the value of this counter can
occur at re-initialization of the management
system, and at other times as indicated by the
value of ifCounterDiscontinuityTime.