Indicate the number of leading one bits which form the mask
to be logical-ANDed with the destination address before
being compared to the value in the cInetCidrRouteDest
field.
Any assignment (implicit or otherwise) of an instance of
this object to a value x must be rejected if the bitwise
logical-AND of the mask formed from x with the value of the
corresponding instance of the cInetCidrRouteDest object is
not equal to cInetCidrRouteDest.