Active Queue Management

Key Points

• Queue control method that acts before buffers become full
• Reduces bufferbloat and improves latency under load
• Used in routers, gateways, and service access devices
• Makes early feedback possible so senders can reduce congestion before delay becomes severe

Definition

Active Queue Management is a queue management approach that actively marks or drops packets before buffers become excessively full. It is designed to limit latency growth.

Concept

Active Queue Management is a networking term used for queue disciplines that intervene before a queue becomes too large. It exists to reduce bufferbloat and improve latency under load. It is used in routers, gateways, and service access devices. AQM makes earlier feedback possible so senders can reduce congestion before delay becomes severe.

Explainer

Active Queue Management works by intervening early in the queueing process so traffic sources can react before latency becomes extreme or buffers overflow. It is used in routers, gateways, access devices, and other network equipment. Constraints include configuration tuning, traffic variation, mark or drop behavior, and the need to avoid making the network overly aggressive. Failure modes include unnecessary loss, unstable sender reaction, poor tuning, and little improvement if the policy does not align with the traffic pattern. Tradeoffs involve lower latency versus earlier packet feedback, better interactive performance versus more control complexity, and proactive congestion signaling versus the risk of overcorrection. Active Queue Management matters because waiting until buffers are full often produces worse user experience than managing queue growth early. Cross-industry relevance is strong in broadband, networking, and service transport.