This read-write enumerated INTEGER (discard/forwardNormal/discardDisable) sets, for the whole interface range in swIfPortLockIfRange, what happens to traffic violating the lock policy, relevant only when those interfaces are in locked mode. Admins use it to apply a consistent violation-response policy across a batch of ports in one operation. For example, setting discardDisable across a range of sensitive ports ensures any unauthorized device plugged into any of them causes that specific port to suspend, rather than configuring each port's action individually.