Software switches are pivotal in the Software-Defined Networking (SDN) paradigm, particularly in the early phases of development, deployment and testing. Currently, the most popular one is Open vSwitch (OVS), leveraged in many production-based environments. However, due to its kernel-based nature, OVS is typically complex to modify when additional features or adaptation is required. To this regard, a simpler user-space is key to perform these modifications.

In this article, we present a rich overview of BOFUSS, the basic OpenFlow user-space software switch. BOFUSS has been widely used in the research community for diverse reasons, but it lacked a proper reference document. For this purpose, we describe the switch, its history, architecture, uses cases and evaluation, together with a survey of works that leverage this switch. The main goal is to provide a comprehensive overview of the switch and its characteristics. Although the original BOFUSS is not expected to surpass the high performance of OVS, it is a useful complementary artefact that provides some OpenFlow features missing in OVS and it can be easily modified for extended functionality. Moreover, enhancements provided by the BEBA project brought the performance from BOFUSS close to OVS. In any case, this paper sheds light to researchers looking for the trade-offs between performance and customization of BOFUSS.

软件开关在软件定义网络（SDN）范例中至关重要，特别是在开发，部署和测试的早期阶段。当前，最流行的一种是在许多基于生产的环境中使用的Open vSwitch（OVS）。但是，由于其基于内核的性质，OVS通常在需要附加功能或改编时很复杂。在这方面，更简单的用户空间是执行这些修改的关键。

在本文中，我们提供了BOFUSS（基本的OpenFlow用户空间软件开关）的丰富概述。由于各种原因，BOFUSS已在研究社区中广泛使用，但缺少适当的参考文件。为此，我们描述了转换，转换的历史，体系结构，用例和评估，以及对利用该转换的作品的调查。主要目标是提供有关开关及其特性的全面概述。尽管原始BOFUSS不会超越OVS的高性能，但是它是有用的补充产品，可提供OVS缺少的一些OpenFlow功能，并且可以轻松对其进行修改以扩展功能。此外，BEBA项目提供的增强功能使BOFUSS的性能接近OVS。任何状况之下，