In modern telecommunication systems and networks causal relationships in the gnoseological (cognitive) plan are not clearly traceable which leads to uncertainty when choosing or building a mathematical model due to incompleteness of the source data (knowledge). It gives rise to multicriterial uncertainty which in turn makes it impossible to solve the problem of a telecommunications network optimal control properly. In such conditions it is difficult to build an adequate model of a telecommunication network based on deterministic and probabilistic-statistical mathematics since there are no objects that can accurately display information vagueness. Therefore it is of interest to develop and research telecommunication systems and networks models using the apparatus of fuzzy sets theory and their influence on decision-making processes on network element state. The paper shows that the use of fuzzy logic to control the resources of a telecommunications network made it possible to create an easily scalable management system the logic of which allows the easy build and change of its structure on a systematic basis by expanding (changing) the rule base. To adjust the membership functions to the nature of the traffic you can apply special operations on fuzzy sets: concentrating and stretching.