Most of softwareized WiFi networks rely on dedicated softwares for realizing novel wireless functionalities. However, such an approach is not flexible enough, and introduces management complexity. On the other hand, the programmable forwarding pipeline, which models packet processing as multiple stages of forwarding rules, exhibits great flexibility in facilitating network innovations, and has been recognized as a consensus for abstracting SDN data plane. In this paper, we present Po-Fi, an architecture for software-defined WiFi networks. Based on Protocol-Oblivious Forwarding (POF), Po-Fi follows the SDN consensus by abstracting WiFi AP as a programmable forwarding pipeline, and provides a rich and unified programmability to enable user to realize novel wireless functionalities with forwarding rules. Comparing with previous approaches, Po-Fi is highly flexible in facilitating WiFi innovations. To show this, we realize a wide range of use cases with Po-Fi, including per-client virtual AP (VAP), seamless mobility, multi-AP MPTCP data transmission, smooth remote AP switching for wireless backhaul, and TDMA MAC scheduling. We implement a Po-Fi prototype with commodity hardware, and evaluate the use cases with real-world experiments. The results show that the Po-Fi facilitated innovations can effectively improve the WiFi network services.

大多数软件化WiFi网络都依赖专用软件来实现新颖的无线功能。然而，这种方法不够灵活，并且引入了管理复杂性。另一方面，可编程转发管道将数据包处理建模为转发规则的多个阶段，在促进网络创新方面显示出极大的灵活性，并且已被公认为抽象SDN数据平面的共识。在本文中，我们介绍Po-Fi，这是软件定义的WiFi网络的架构。Po-Fi基于协议无关转发（POF），通过将WiFi AP抽象为可编程转发管道来遵循SDN共识，并提供丰富而统一的可编程性，使用户能够通过转发规则实现新颖的无线功能。与以前的方法相比，Po-Fi在促进WiFi创新方面具有很高的灵活性。为了说明这一点，我们通过Po-Fi实现了广泛的用例，包括每客户端虚拟AP（VAP），无缝移动性，多AP MPTCP数据传输，用于无线回程的平滑远程AP切换以及TDMA MAC调度。我们使用商品硬件实施Po-Fi原型，并通过实际实验评估用例。