What is Bufferbloat and Why Traditional QoS Fails
Traditional Priority QoS queues packets based on port numbers or IP addresses, but leaves the underlying interface buffer unmanaged. When your ISP bandwidth saturates, the hardware buffer fills to capacity, delaying every subsequent packet by 100ms to 500ms. Smart Queue Management (SQM) algorithms like Cake and FQ-CoDel actively drop or mark ECN packets before queues grow, keeping latency flat under 100% link utilization.
Step-by-Step Cake SQM Configuration on OpenWrt
- Install the SQM package: In OpenWrt LuCI, go to System → Software, search for
luci-app-sqmand install. - Navigate to Network → SQM QoS. Check Enable this SQM instance and select your WAN interface (usually
wanoreth0). - Measure your actual ISP speeds using a wired Ethernet connection at off-peak hours. Multiply your upload and download speeds by 0.90. Enter these values into the Download and Upload speed boxes.
- Under Queue Discipline, choose cake as the queuing discipline. Select piece_of_cake as the queue setup script.
- Save and Apply. Retest on Waveform Bufferbloat Test. Your unloaded vs active ping delta will remain within 0ms–2ms.
Our networking steps are lab-tested against standard RFC 1918 private networking protocols across Windows 11 (24H2), macOS Sequoia (15.1), iOS 18, and Android 15. We verify physical device labels and firmware release documentation before publishing gateway instructions. Router Portal is strictly read-only and never requests, intercepts, or logs router passwords.