LazyAS: Client-Transparent Access Selection in Dual-Band WiFi

Dual-band WiFi which supports both 2.4GHz and 5GHz has been widely deployed, aiming to expand wireless capacity and eliminate serious interference in 2.4GHz. Thus, how to select which band to access to achieve considerable user experience is becoming essential in wireless network. Clients' native decision that always prefers 5GHz will consequently cause serious interference in 5GHz and leave 2.4GHz notably idle. Through analyzing a unique dataset in the wild, we quantitatively study the impact of various WiFi factors on the wireless delay. We propose a decision tree approach for intelligent access selection that decides which band to access dynamically according to prior learned schemes. A prototype of the access selection system named LazyAS, which only requires modification at AP side, is realized and deployed in production WiFi network. Evaluation results demonstrate that our proposed LazyAS reduces the 90th percentile of wireless delay in the production WiFi network from 32ms to 12ms.