16 research outputs found
Piece of CAKE : A Comprehensive Queue Management Solution for Home Gateways
The last several years has seen a renewed interest in smart queue management tocurb excessive network queueing delay, as people have realised the prevalence of bufferbloat in real networks. However, for an effective deployment at today's last mile connections, animproved queueing algorithm is not enough in itself, as often the bottleneckqueue is situated in legacy systems that cannot be upgraded. In addition,features such as per-user fairness and the ability to de-prioritise backgroundtraffic are often desirable in a home gateway. In this paper we present Common Applications Kept Enhanced (CAKE), a comprehensive network queue management system designed specifically for homeInternet gateways. CAKE packs several compelling features into an integratedsolution, thus easing deployment. These features include: bandwidth shaping withoverhead compensation for various link layers; reasonable DiffServ handling;improved flow hashing with both per-flow and per-host queueing fairness; andfiltering of TCP ACKs. Our evaluation shows that these features offer compelling advantages, andthat CAKE has the potential to significantly improve performance of last-mileinternet connections
Ending the Anomaly : Achieving Low Latency and Airtime Fairness in WiFi
With more devices connected, delays and jitter at the WiFi hop become more prevalent, and correct functioning during network congestion becomes more important. However, two important performance issues prevent modern WiFi from reaching its potential: increased latency under load caused by excessive queueing (i.e. bufferbloat) and the 802.11 performance anomaly. To remedy these issues, we present a novel two-part solution. We design a new queueing scheme that eliminates bufferbloat in the wireless setting. Leveraging this queueing scheme, we then design an airtime fairness scheduler that operates at the access point and doesn't require any changes to clients. We evaluate our solution using both a theoretical model and experiments in a testbed environment, formulating a suitable analytical model in the process. We show that our solution achieves an order of magnitude reduction in latency under load, large improvements in multi-station throughput, and nearly perfect airtime fairness for both TCP and downstream UDP traffic. Further experiments with application traffic confirm that the solution provides significant performance gains for real-world traffic.We develop a production quality implementation of our solution in the Linux kernel, the platform powering most access points outside of the managed enterprise setting. The implementation has been accepted into the mainline kernel distribution, making it available for deployment on billions of devices running Linux today