A fault tolerant NoC architecture based upon external router backup paths

As the scale of integration of digital circuits increases, there is a corresponding increase in the probability of permanent failures in NoCs. As a result, it is essential that NoCs have fault tolerance mechanisms in order to cope with this issue. In this article, we present a NoC architecture for a fault-tolerant multiprocessor chip based upon the use of backup paths which are external to the router, which allows maintaining communication between non-faulty network´s routers. In the event of a permanent failure in a router, the control mechanism of backup paths is triggered in such a way that the faulty router is by-passed and the data is routed in a transparent way. Thus, data going through the faulty router from east to west and from north to south go all the way through to the final destination. The routing algorithm used in this version of the architecture uses a modified version of the XY routing algorithm. The results of performance evaluation show that the proposed architecture has a higher resiliency and provides lower latency than NoCs that make use of partially adaptive or stochastic algorithms.