However, standard Ethernet is not a viable solution for industrial control infrastructure given the need for real-time operation. Operational technology (OT) control networks need to ensure that the message being communicated is delivered to where it is needed on time. This ensures the correct operation of the task or process at hand. The TCP/IP protocol for routing traffic does not inherently guarantee this level of deterministic performance. In the same way that standard Ethernet enables file sharing or access to network devices such as printers, Industrial Ethernet allows controllers to access data and send instruction commands from PLCs to sensors, actuators, and robots dispersed across the factory floor. The key difference is the impact of delayed or undelivered messages. In non-real-time applications, if the webpage is slow to update, the impact is minimal, while in a manufacturing environment, the impact can be high, from wasted materials to accidental human harm. For control systems to work, the message must get to its destination reliably, on time, every time.
As a result, Industrial Ethernet has emerged as the technology of choice at the control level of the operating technology. The goal is to enable seamless connectivity not just between the IT and high level OT networks, but right down through the various layers of the factory’s OT network to the end node sensor, as illustrated in Figure 3. Today, complex, power hungry gateways are required to enable connectivity from the lower levels of the OT network, to Ethernet at higher layers, where a converged IT/OT network is required. Having a plant-wide, interoperable automation network based on Ethernet would eliminate the need for these gateways, thereby simplifying the network itself. In fact, protocol gateways used to translate and enable connection to the upper layer of the OT network are not directly addressable and have resulted in isolation in the network. This data isolation limits the ability to share information across the factory floor. This is contrary to the vision of Industry 4.0 outlined earlier, where manufacturers want to collect telemetry data from the OT side to drive analytics and business processes on the IT side.