Abstract—Using a unique monitoring experiment, we capture all packets crossing a (lightly utilized) operational,access router from a Tier-1 provider, and use them to provide a detailed ex- amination,of router congestion and,packet delays. The complete capture enables not just statistics as seen from outside the router, but also an accurate,physical router model,to be identified. This enables,a comprehensive,examination,of congestion,and,delay from three points of view: the understanding of origins, mea- surement, and reporting. Our study defines new methodologies and metrics. In particular, the traffic reporting enables a rich description of the diversity of microcongestion behavior, without model assumptions, and at achievable computational cost.