On a Definition object -- a network-control policy definition that governs discovery-protocol and uplink-failure behavior for a vNIC/vHBA template or service profile -- cucsNwctrlDefinitionPropAcl is an Unsigned64 bitmask encoding the property-level access-control list bits governing which properties of this object can be modified and by whom. An admin or management tool decodes this bitmask bit-by-bit to determine exactly which conditions or permissions apply to that specific Definition instance, since a single flag couldn't hold this much detail. For example, a management application reading cucsNwctrlDefinitionPropAcl would inspect individual bits to know which specific properties are affected, without exposing every bit as a separate SNMP object.