Using benes networks at fault-tolerant and deflection routing based network-on-chips

Fault tolerance and energy consumption are two key aspects of future Network-on-Chips (NoCs). The utilization of deflection routing and Banyan networks for fault-tolerant and energy efficient router architectures was proposed recently. Compared to traditionally deployed crossbars, Banyan networks can reduce hardware costs and improve the energy efficiency of router architectures. However, they also cause substantial disadvantages in terms of fault tolerance, as they are internal blocking, single-path networks. In contrast, Benes networks have some considerable advantages if they are used for fault-tolerant NoCs, as they are rearrangeable non-blocking, multi-path networks. In this paper, we identify the problems of Banyan networks when it comes to fault tolerance. Further, we show that a router architecture, which is instead based on a Benes network, can solve all identified problems, if constructed carefully. Comparisons to existing fault-tolerant and deflection routing based NoCs are presented. The achieved results show, that compared to Banyan networks, Benes networks can improve the performance at almost no additional hardware costs.