Abstract
Reliability is one of the most important characteristics of the functioning of supply chains. The carried out analysis have shown that, despite some progress, a number of questions remain open, in particular, the terminology, the selection of key indicators and methods of their calculation as well as there is no economic evaluation of redundant and restorable supply chains. The paper presents a formed conceptual apparatus of logistics systems' reliability theory, the discrete-continuous model of the simple supply chain’s functioning as well as it contains the proposal to assess the reliability not only with the help of faultlessness but as well by using the leading function of costs associated with the maintenance of supply chains’ operability