OT refers to the hardware and software dedicated to detect or induce changes in physical processes. OT involves technologies that are used to directly monitor and/or control physical devices such as valves, pumps, and so on. As an example, consider the computing and connectivity technologies involved in an ICS/SCADA system of a power station or a railway locomotive manufacturing facility, which monitors and controls the various physical systems and plant processes.

By adopting IoT, as industries accelerate into the future, it is important to evaluate the current industrial assets and technologies in a typical industrial deployment, and to determine practical mechanisms to transition to greater efficiencies without compromising resiliency. So, before diving deeper into the subject of IIoT security, the prevalent industrial devices, systems, and technologies are discussed in this section.