Edge Cache on WiFi Access Points: Millisecond-Level App Latency Almost for Free
Zhengquan Li, Summit Shrestha, Zheng Song, Eli Tilevich · 2024
To achieve low execution latency, time-sensitive applications, including AR/VR and autonomous driving, cache data at the edge of the network, close to end users. However, existing edge caches often fail to deliver low latency due to the inefficiency of DNS requests and the physical remoteness of their users. The solution described herein addresses these inefficiencies by presenting a millisecond-level, lightweight caching architecture that operates directly on widely deployed WiFi access points (APs). Specifically, our architecture interposes another level of caching closer to the client and is fine-tuned for APs's limited cache memory. Our solution (1) features a novel algorithm for managing cache at the AP level; (2) allows the cache query workflow to proceed at full speed; and (3) requires no changes to the application logic. Our evaluation demonstrates that our reference implementation can decrease application-level latency by as much as 76% compared to the existing solutions, without impacting AP core functions. Our caching architecture effectively improves application responsiveness by tapping into existing networking infrastructure, thus offering a powerful and cost-efficient system component for building emerging time-sensitive applications at the edge.