This sets the alert period, in minutes, over which this port evaluates ingress framer FIFO overflow events before declaring a threshold-crossing alert. A framer FIFO overflow on this specific port happens at the physical-layer ingress buffer stage before cells even reach ATM-layer processing, so this alert period governs how quickly a hardware-level receive bottleneck on this port, as opposed to any of the QoS-class egress overflow conditions, gets escalated. Because framer FIFO overflows point to a lower-level hardware bottleneck rather than a QoS class congestion issue, an admin might set this alert period shorter than the egress buffer overflow periods to catch this more fundamental fault sooner.