Slice router: For fine-granularity fault-tolerant Networks-on-Chip

Almost all existing Networks-on-Chip (NoC) fault-tolerant schemes are based on fault-tolerant routing algorithms. In these fault-tolerant schemes, faulty links or routers will be discarded all together. However, only a few part of the discarded link or router is faulty in most cases. It is wasteful to discard the whole link or router. In this paper, we present a slice router architecture which can be used in fine-granularity fault-tolerant NoC. The major motivation of presenting slice router is to refine faulty links and routers. The major idea is that a router is split into several sub-link routers, noted slices. Different from several physically independent routers, slices are coupled together in input/output ports. The coupling of slices makes the network to be able to fine-granularity fault-tolerant. In order to evaluate the fault-tolerant capability of slice routers, we design a loosely-coupled 4-slices router with a backup sub-link in each link. Each slice is a single-cycle output buffered switch. Simulation results prove its fault-tolerant capability in the present of high faulty rates. The critical latency is only increased 0.04ns, because the configuration of slice interfaces is parallel with the output arbiter of slices. Under 65nm technology synthesized results show that, the increased area overhead of a slice router is only a few logic gates compared with the non-coupled slice router.