Towards a General Solution for Detecting Traffic Differentiation at the Internet Access

摘要

In recent years network neutrality has been widely debated from both technical and economic points of view. Various cases of traffic differentiation at the Internet access have been reported throughout the last decade, in particular aimed at bandwidth consuming traffic flows. In this paper we present a novel application-agnostic method for the detection of traffic differentiation, through which we are able to correctly identify where a shaper is located with respect to the user and evaluate whether it affected delays, packet losses or both. The tool we propose, ChkDiff, replays the user's own traffic in order to target routers at the first few hops from the user. By comparing the resulting flow delays and losses to the same router against one other, and analyzing the behaviour on the immediate router topology spawning from the user end-point, ChkDiff manages to detect instances of traffic shaping. We provide a detailed description of the design of the tool for the case of upstream traffic, the technical issues it overcomes and a validation in controlled scenarios.