claims by companies that the bandwidth demands of online services exceeds current availability. However, the allegations of throttling we attempt to address differ substantially from these debates in scope and execution, and fit into a history of interference with the free flow of information, offline and online, and recurrent security intrusions on the end-to-end privacy of the communication of users, often originating from government-affiliated actors [@foxitdiginotar].

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Degradations in network performance and content accessibility can be the product of a number of phenomenon and externalities, localized to one point or commonly experienced across a wider range of Internet users. In order to accurately and definitively measure broadly-targeted degradation, such as throttling, it is necessary to obtain data from a diversity of hosts, in terms of connection type, physical location, time of usage and nature of usage.

A number of tools have been developed to actively probe qualities of infrastructure directly relevant to throttling and disruption [@dischinger2010glasnost; @filasto2012ooni; @kreibich2010netalyzr]. These techniques compare whether traffic flows of differing types sent at an identical rates are received differently, thereby comparing against an established baseline to give a clear indication of potential discrimination. Where such data has been core to network neutrality 