\input zb-basic \input zb-ioport \iteman{io-port 05553313} \itemau{Lekadir, Ouiza; Aissani, Djamil} \itemti{Stability of two-stage queues with blocking.} \itemso{Le Thi, Hoai An (ed.) et al., Modelling, computation and optimization in information systems and management sciences. Second international conference MCO 2008, Metz, France - Luxembourg, September 8--10, 2008. Proceedings. Berlin: Springer (ISBN 978-3-540-87476-8/pbk). Communications in Computer and Information Science 14, 520-529 (2008).} \itemab Summary: Queueing networks are known to provide a useful modeling and evaluation tool in computer and telecommunications. Unfortunately, realistic features like finite capacities, retrials, priority, \dots usually complicate or prohibit analytic solutions. Numerical and approximate computations as well as simplifications and performance bounds for queueing networks therefore become of practical interest. However, it is indispensable to delimit the stability domain wherever these approximations are justified. In this paper we applied for the first time the strong stability method to analyze the stability of the tandem queues $\left[M/G/1 \rightarrow ./M/1/1\right]$ . This enables us to determine the conditions for which the characteristics of the network with retrials $\left[M/G/1/1 \rightarrow ./M/1/1\right]$ , can be approximated by the characteristics of the ordinary network $\left[M/G/1 \rightarrow ./M/1/1\right]$ (without retrials). \itemrv{~} \itemcc{} \itemut{queueing networks; tandem queues; stability; retrials; blocking; Markov chain} \itemli{doi:10.1007/978-3-540-87477-5\_55} \end