Final answer:
Traffic shaping is the QoS mechanism that sets bandwidth limits and delays excess traffic rather than dropping packets to manage congestion.
Step-by-step explanation:
The Quality of Service (QoS) mechanism that can set a bandwidth limit on traffic and delays packets, rather than drops packets, attempting to exceed that bandwidth limit is a) Traffic shaping. Traffic shaping is used to control the volume of traffic being sent into a network in a specified period of time to prevent congestion. Unlike policing, which can drop excess packets outright, traffic shaping will delay excess packets by placing them in a queue, thus applying a form of congestion management and controlling the rate of traffic flow.