Which per-hop traffic-control action limits or drops traffic when a customer exceeds its committed bandwidth?

Policing is the per-hop traffic-control action that immediately drops or re-marks traffic that exceeds a configured rate. It enforces a hard limit, discarding excess traffic instantly. This is often used at network ingress points to protect the network from over-subscription. Queuing buffers excess traffic for later transmission, rather than dropping it immediately. Marking changes the QoS (Quality of Service) bits of a packet, but doesn't drop or delay it. Shaping smooths out traffic bursts by delaying packets to conform to a desired rate, but it doesn't drop traffic unless the buffer overflows.