Some embodiments provide a statistics collection framework that is used to aggregate statistic for interfaces such as logical ports and logical port pairs. Flows that are related with these interfaces are tagged with the identifier of the logical entities for which statistics are being collected. The interface statistics is periodically sent in the background to a statistics aggregator. The read queries for the interface statistics are directed to the statistics aggregator. The statistics aggregator, therefore, acts as a cumulative cache for the interface statistics.