The IEEE 1500 standard structure provides a test wrapper to test routers and a bypass to shield faulty routers.However

if a bypass fails

not only we cannot use it to tolerate fault

but also it will disturb other test responses in the same scan chain.To solve the problem

we propose a diagnostic method for bypass fault in routers' test wrapper in NoC.We use the Depth-first shortest path to get the shortest path from the scan-in port to the scan-out port

and we separate routers by using recursive partitioning stepwise refinement to construct multiple scan test chains.So the localization of bypass fault could be realized.Then we also propose an architecture to tolerate the bypass fault.