This read-write field sets whether the individual-address screening policy, whose membership bitmap lives in lportSmdsIaScrnMap, operates as an allow-list or a disallow-list for this interface's SMDS individual-address traffic. An admin picks allow when only a short list of specific SMDS peers should be reachable, a closed user group, or disallow when most addresses should be reachable except a small blocked set. For example, setting lportSmdsIaScrnOp to allow(1) means only the individual addresses explicitly marked in lportSmdsIaScrnMap can communicate with this port, appropriate for a tightly closed SMDS user group.