Towards a middlebox policy taxonomy: Path impairments

Recent years have seen the rise of middleboxes, such as firewalls, NATs, proxies, or Deep Packet Inspectors. Those middleboxes play an important role in today's Internet, including enterprise networks and cellular networks. However, despite their huge success in modern network architecture, they have a negative impact on the Internet evolution as they can slow down the TCP protocol evolution and its extensions. Making available a summary of the potential middlebox network interferences is of the highest importance as it could allow researchers to confront their new transport protocol to potential issues caused by middleboxes. And, consequently, allowing again innovation in the Internet. This is exactly what we tackle in this paper. We propose a path impairment oriented middlebox taxonomy that aims at categorizing the initial purpose of a middlebox policy as well as its potential unexpected complications. Based on a measurement campaign on IPv4 and IPv6 networks, we confront our taxonomy to the real world. Our dataset is freely available.