This read-write flag enables or disables CLP tagging on ingress cells, meaning whether the card will mark excess (non-conforming to the stricter rate) cells with CLP=1 rather than discarding them outright when UPC detects they exceed the tighter contract but still fit within the looser one. Admins enable this to let a connection's excess traffic degrade gracefully (marked low-priority, eligible for discard downstream) instead of being dropped immediately at ingress. For example, enabling ingrUpcCLPTagEnable on a VBR connection lets bursts exceeding the SCR be tagged CLP=1 and passed on, rather than being discarded right at the ingress policing point.