Traffic shaping is the QoS mechanism that queues excess packets and transmits them later to conform to a configured rate. In Cisco QoS design, shaping smooths bursts by buffering traffic instead of immediately discarding it when the offered rate exceeds the configured rate. This makes shaping appropriate on egress interfaces where the enterprise router has a higher physical interface speed than the actual provider committed information rate. WRED and RED are congestion-avoidance mechanisms that drop packets probabilistically to prevent full queue exhaustion, especially for TCP traffic. They do not intentionally hold excess packets for later transmission as the primary behavior. Policing enforces a traffic rate by dropping or remarking traffic that exceeds the configured contract; it does not buffer traffic to smooth bursts. Therefore, when the design requirement says excess packets must be queued for later transmission, the mechanism must be shaping. In WAN edge QoS, shaping is often paired with child queuing policies so latency-sensitive and business-critical classes receive correct treatment inside the shaped parent rate.