The concept of D-spectrum is a useful tool to investigate the reliability and stochastic properties of networks. In this paper, we consider a network consisting of components (links or nodes), and assume that the network has two states: up, and down. We study the D-spectrum-based reliability of the network under the assumption that the components are subject to failure according to a counting process. Mixture representation of the reliability of the network lifetime is given in terms of the reliability functions of arrival times. It is shown that, when the D-spectra of two networks are stochastically ordered, then under some conditions the lifetimes of two networks are also stochastically ordered. Under the special case when the process of the failure of the components is a nonhomogeneous Poisson process, we arrive at a mixture representation for the reliability function of the network lifetime, and explore several stochastic and aging properties of the network lifetime under different scenarios. The failure rate of the network lifetime and its asymptotic behavior is investigated. D-spectrum based representation theorems are also given on the basis of the stochastic precedence concept.Index Terms-D-spectrum, increasing failure rate, nonhomogeneous Poisson process, record values, stochastic ordering, stochastic precedence, system signature, two-state networks.
ACRONYMSAND ABBREVIATIONS NHPP Nonhomogeneous Poisson process NBU New better than used NWU New worse than used MRL Mean residual lifetime m.v.f. Mean value function IFR Increasing failure rate DFR Decreasing failure rate NOTATIONS the node set of network the link set of network Manuscript