The subnet mask and cgkZoneSubnetAddress must have the
relationship
(cgkZoneSubnetAddress & cgkZoneSubnetMask) ==
cgkZoneSubnetAddress
that is the bitwise AND of cgkZoneSubnetAddress with
cgkZoneSubnetAddress must equal cgkZoneSubnetAddress otherwise
the set request shall fail with a 'inconsistentValue' error.
This object is required for row creation.