Separable networks with unreliable servers

We model and analyse stochastic networks with unreliable servers which have various applications, e.g. in telecommunication networks and production systems. Starting from standard BCMP networks, we introduce degradable network models where we incorporate breakdowns of servers and their repair. Breakdowns and repairs occur in different ways: Concurrently in groups or single nodes. Working and repair periods are determined by state dependent intensities. We apply different rules for the customers' routing connected with nodes in repair status. These rules originate from communication and/or production theory where they are used to resolve blocking situations. The main results are steady state distributions of product form for the supplemented Markovian network processes.