Which traffic-conditioning mechanism buffers packets during congestion instead of dropping them?

Policing drops or remark excess packets immediately when the traffic rate exceeds a configured threshold, rather than buffering them, making it a reactive dropping mechanism.

Per-Hop Behavior (PHB) is a classification and forwarding behavior applied to traffic based on its DSCP marking, defining how packets should be treated by network devices; it is not a mechanism for buffering and releasing packets during congestion.

Class-Selector PHB is a specific type of PHB that maintains backward compatibility with IP Precedence, mapping IP Precedence values to DSCP values, and like general PHBs, it is not a buffering mechanism.

Traffic shaping buffers excess packets when the traffic rate exceeds a configured threshold, holding them in a queue and then releasing them at a controlled, smoother rate over time. This prevents packets from being dropped immediately during bursts of congestion, ensuring higher reliability for applications.