Real-Time Video Gets a Fast Lane via Smart Queue Flushing at the Wireless Edge

Real-time communication (RTC) applications demand not only low average latency but also tight tail-delay bounds to ensure smooth user experience. However, sudden fluctuations in wireless networks can cause in-flight packets to accumulate in bottleneck queues, delaying or invalidating subsequent frames. Traditional mechanisms focus on rate adaptation but largely overlook managing already enqueued packets that contribute to tail delay. We present Gecko, a lightweight end-to-network coordination mechanism that enables frame-aware queue flushing without requiring any in-network packet modification or protocol negotiation. Gecko-enabled routers monitor queuing delay and implicitly signal the sender, which then makes frame-skipping decisions and conveys flushing intent through minimal in-band RTP markings. This approach preserves end-to-end integrity and is broadly compatible with existing RTC applications. We evaluate Gecko via trace-driven simulations and real-world experiments. Results show that Gecko reduces average frame delay by 21.8% and cuts tail-delay frame ratios by 25% to 91%, demonstrating both its effectiveness and deployability in wireless RTC environments.