Glasnost: Enabling End Users to Detect Traffic Differentiation

Holding residential ISPs to their contractual or legal obligations of “unlimited service ” or “network neutral-ity ” is hard because their traffic management policies are opaque to end users and governmental regulatory agen-cies. We have built and deployed Glasnost, a system that improves network transparency by enabling ordi-nary Internet users to detect whether their ISPs are dif-ferentiating between flows of specific applications. We identify three key challenges in designing such a sys-tem: (a) to attract many users, the system must have low barrier of use and generate results in a timely man-ner, (b) the results must be robust to measurement noise and avoid false accusations of differentiation, which can adversely affect ISPs ’ reputation and business, (c) the system must include mechanisms to keep it up-to-date with the continuously changing differentiation policies of ISPs worldwide. We describe how Glasnost addresses each of these challenges. Glasnost has been operational for over a year. More than 350,000 users from over 5,800 ISPs worldwide have used Glasnost to detect dif-ferentiation, validating many of our design choices. We show how data from individual Glasnost users can be aggregated to provide regulators and monitors with use-ful information on ISP-wide deployment of various dif-ferentiation policies.