A system and method for policing individual flows and subflows of a data stream. Data traffic streams are classified into separate traffic flows, which in turn can be further classified into subflows, thereby providing for different priority levels of subsets of the flow. The subflows may be still further classified into additional subflows, creating a hierarchical, layered prioritization that can be metered at each vertical and horizontal level of the hierarchy. A packet flow rate of each of the subflows is compared to a predefined rate limit to allow subflows of a flow to have different priorities therebetween.