1. A method, comprising: repeatedly detecting at least one parameter of at least one observable object of a network; checking the at least one parameter with regard to fulfilling predetermined criteria; and forming a vector based on the at least one parameter depending on whether the at least one parameter fulfills the predetermined criteria, wherein the vector comprises several values which describe properties or functioning of the observable object, and the formed vector is evaluated to monitor a behavior of the observable object, and wherein a number of parameters that fulfill the predetermined criteria during an observation period, is counted, to form key performance indicator (KPI) values which form part of the vector, each parameter having its own criteria.