An indication of the validity of the network prefix for ATM addresses on the user side of the UNI port. To configure a new network prefix in this table, the network-side IME must set the appropriate instance of this object to the value valid(1). To delete an existing network prefix in this table, the network-side IME must set the appropriate instance of this object to the value invalid(2). If circumstances occur on the user-side IME which cause a prefix to become invalid, the user-side IME modifies the value of the appropriate instance of this object to invalid(2). Whenever the value of this object for a particular prefix becomes invalid(2), the conceptual row for that prefix may be removed from the table at any time, either immediately or subsequently.