Design and evaluation of a fault-tolerant adaptive router for parallel computers

In this paper, we propose a design methodology for fault-tolerant adaptive routers for parallel and distributed computers. The key idea of our method is integrating minimal and non-minimal routing that is supported by independent virtual channels (VCs). Distinguishing the routing functions for each set of VCs simplifies the design of fault-tolerant algorithms. After describing the method, we show an application of a routing algorithm for two-dimensional mesh and torus networks. This algorithm, called Detour-NF, supports three routing modes: deterministic, minimal fully adaptive and non-minimal fault-tolerant operations. We also discuss the hardware cost and operational speed of minimal and non-minimal routers based on our design, which uses hardware description language (HDL). Communication performance and fault-tolerance are demonstrated by an HDL simulation. The experimental results show that supporting both minimal and non-minimal routing modes is advantageous for high-bandwidth and low-latency communication, as well as fault-tolerance.