The perspective of nanometric technologies foreshadows the advent of processors consisting of hundreds of computation cores. However, the exploitation of these processors will require to cope with reliability and variability issues inherent to these aggressive manufacturing processes. In this thesis, we present a coherent set of techniques for the utilization of many-cores processors subject to high defect and variability rates. First, the interconnection network reliability is addressed, with the presentation of several deadlock-free fault-tolerant routing algorithms, without routing tables for improving their scalability. The different variants of these algorithms allow for the tune-up of NoC complexity, depending on applications' reliability requirements. For example, the most performant routing algorithm is able to transmit packets as long as a fault-free path exists, with defect rates as high as 40%. Evolutions have also been studied, in order to improve the interconnect performances in the presence of a large number of faults. Second, we propose a self-adaptive technique for the management of parallel applications, based on a fault-tolerant interconnect. The dynamic tasks mapping is based on the adaptive search of computing nodes, in order to reduce the application's energy consumption in the presnece of variability. Third, we present a high-level simulation model named VOCIS (Versatile On-Chip Interconnect Simulator), developed during this thesis. The model allows in-depth study of interconnection networks and fault-tolerant routings under complex settings, in order to meet the specific constraints of this work. The architecture and visualization features are described. Finally, we analyse and illustrate original experimental results obtained with this model.