This counts high-priority CLP0 cells that were checked by the switch's Usage Parameter Control policing function and found to be within the circuit's contracted traffic parameters, so they were passed through cleanly rather than tagged or dropped. An admin comparing this counter to cktAtmInDiscardedClp0Cells over the same period gets a compliance ratio showing what fraction of this circuit's protected traffic is conforming versus violating its contract. For example, a circuit showing millions of passed CLP0 cells and zero discarded ones demonstrates the customer is staying well within their committed traffic parameters for their protected traffic class.