The aim of this work is to propose a novel methodology for quantification of datacommunication network availability. Currently used reliability calculation model is not very suitable for networking environment with many-to-many type of communication. In this paper we propose a novel method to quantify service availability in datacommunication networks. The proposed method reflects the multipoint-to-multipoint nature of datacommunication. The main idea of the proposed method is utilization of a special class of mathematical operations called t-norms.