1. A method of extracting a communication network behavioral metric based on a relevancy of the metric to network behavior, comprising: identifying a network metric x that is defined as a random variable that represents a quantitative measure of a network behavior accumulated over a period of time; selecting a network feature; generating a metric disintegration model for the network metric x comprising at least one normal behavior probability distribution function for the metric x for each value of the network feature, respectively, and at least one abnormal behavior probability distribution function for the metric x for each value of the network feature, respectively; increasing a number of the values of the metric x that indicates normal network behavior and/or abnormal network behavior based on the metric disintegration model; and selecting a network metric x as a behavioral metric based on a relevancy η of the network metric x to the network behavior; wherein the relevancy η is given as follows: η =  Φ sn  +  Φ sa   Φ  Φ is a sample space of all possible values of x; Φ sn is a subset of Φ based on the values of x that indicates normal network behavior; Φ sa is a subset of Φ based on the values of x that indicates abnormal network behavior.