This is the highest value recorded during the current performance-monitoring interval of the percentage of ingress capacity being used on this interface during the current performance-monitoring interval. The highest utilization seen in the interval flags the busiest moment, which is what an admin checks first when trying to explain a customer's reported slowdown. For example, if a customer complains about slow transfers at 9 a.m. every day, an admin would check whether inUtilizationMax for that hourly interval consistently approaches full capacity, confirming genuine congestion rather than a fault.