A count of OAMPDUs received that contain the Variable
Response code specified in Table 57-4. This counter is
incremented on reception of a valid frame, with (1)
destinationField equal to the reserved multicast address
for Slow_Protocols specified in CROSS REF Table 43B-1, (2)
lengthOrType field value equal to the reserved Type for
Slow_Protocols as specified in CROSS REF Table 43B-2, (3)
a Slow_Protocols subtype value equal to the subtype
reserved for OAM as specified in Table 43B-3, (4) the OAM
code equals the Variable Response code and is supported by
the device.