1. A method, comprising: obtaining an all-distance bottom-k sketch; computing adjusted weights of the all-distance bottom-k sketch via a Markov-chain based method by utilizing a processor; deriving a bottom-k sketch from the all-distance bottom-k sketch by utilizing the processor; applying the adjusted weights to items in the bottom-k sketch by utilizing the processor; estimating properties of flows through a router based upon the adjusted weights of the all-distance bottom-k sketch of the flows and based on corresponding estimators of a k-min sketch associated with the all-distance bottom-k sketch; estimating a size of subpopulations of items of the flows based on the adjusted weights; and calculating a selectivity of the subpopulations based on the adjusted weights.