# PoliFi: Airtime Policy Enforcement for WiFi

## TL;DR

PoliFi is a system that extends airtime fairness in WiFi to enforce various network policies, such as prioritization and limiting device groups, improving performance and fairness.

## Contribution

This work extends previous airtime fairness mechanisms to enable policy enforcement in WiFi networks through a new system called PoliFi.

## Key findings

- PoliFi can enforce prioritization of specific devices.
- It balances device groups across network slices.
- It improves DASH video streaming performance.

## Abstract

As WiFi grows ever more popular, airtime contention becomes an increasing problem. One way to alleviate this is through network policy enforcement. Unfortunately, WiFi lacks protocol support for configuring policies for its usage, and since network-wide coordination cannot generally be ensured, enforcing policy is challenging. However, as we have shown in previous work, an access point can influence the behaviour of connected devices by changing its scheduling of transmission opportunities, which can be used to achieve airtime fairness. In this work, we show that this mechanism can be extended to successfully enforce airtime usage policies in WiFi networks. We implement this as an extension our previous airtime fairness work, and present PoliFi, the resulting policy enforcement system. Our evaluation shows that PoliFi makes it possible to express a range of useful policies. These include prioritisation of specific devices; balancing groups of devices for sharing between different logical networks or network slices; and limiting groups of devices to implement guest networks or other low-priority services. We also show how these can be used to improve the performance of a real-world DASH video streaming application.