Fog computing has been widely adopted to meet the performance of explosive growth of IoT applications. In both 5G and IoT applications, low latency and ultra-reliable communication are two key features which cloud-based only architecture cannot meet those performance requirements. Fog computing which adds a hierarchy of elements between the cloud and endpoint devices can meet those requirements in a secure, high performance, open, and interoperable way. To validate whether future fog node products can meet trusted computing criteria and performance requirements or not, a common testbed is necessary. In this paper, we will first discussion the security practice (the fundamental pillar of OpenFog architecture) required for future testbed designs. National Chiao Tung University (NCTU) is leading to attempt to provide Security-as-a-Service (SECaaS) in NCTU testbed based on 4G wireless networks and two other fog enabled testbeds provided by ITRI's smart lamp posts testbed and Shanghai Tech's software defined (SD) LTE fog nodes testbed are also discussed for rapid prototyping of vertical industry applications. Two use cases, indoor autonomous vehicle and BATS codes multihop wireless will also be presented as the potential examples for testbeds.