Abstract: The present invention optimises and reduces the needed information exchange between network entities through the interfaces which connect them. The main property of the event based reporting method of the present invention is its flexibility because it is able to change the reporting rate depending on the value of the input parameter in each instant of time. That is, it sends more reports or less reports depending on if the parameter to be reported is changing quickly or slowly, respectively. The main idea of the present invention is that reports of a data network parameter are based on the relative change of the data network parameter value with respect to the previously reported data network parameter value.