This read-create value, ranging 5-100 and defaulting to 50, sets the percentage probability that a packet is discarded once the port's rate-limit threshold has been reached. A higher probability drops offending traffic more aggressively once the port is flagged as under load; a lower one is more lenient. An admin dealing with a persistent flood might raise this from the default 50 to 90 so most excess packets on that port get dropped once the threshold trips.