This value sets the lower limit, below the upper limit and measured over a 1-second interval in the unit chosen by hh3cStormCtrlMulticastUnit, that multicast traffic must fall under before a controlled port is restored to normal forwarding. An admin uses the gap between the upper and lower values to add hysteresis and avoid rapid flapping between controlled and normal status. For example, a multicast upper limit of 10000 kbps paired with a lower limit of 8000 kbps keeps the port blocked until traffic drops well below the storm threshold.