Alibaba Alibaba Huawei Technologies Huawei Technologies Cisco Systems H3C H3C In VXLAN overlay networks, Operation and Management(OAM)functions are important for fault management and performance monitoring. Path Detection(PD) is one critical OAM function which is applied to monitor and/or diagnose the potential paths between two VTEPs or between two Tenant System. In addition, it can assist to identify the locations of failures on data transmission paths. This document specifies a method of PD method for VXLAN Overlay Networks by using a centralized controller. However,the method can be easily extended to support the overlay networks without a centrilized controller. It can also be generalized to other overlay technique such as NVGRE.