Tunnelling and Mirroring Operational Technology Data with IP-based Middlewares

Accessing runtime information originated from Operational Technology (OT) communication protocols by Information Technology (IT) applications remains a challenging task. Middlewares and gateways could provide a possible solution to bridge this OT/IT gap. In this context, this paper examines the feasibility of interconnecting legacy OT protocols via different middlewares and gateways by presenting two simplified scenarios. Each scenario exemplifies a possible use-case by either mimicking bidirectional tunnelling or propagating (mirroring) of automation data. Both scenarios use OPC Unified Architecture (OPC UA) and Message Queuing Telemetry Transport (MQTT) and a respective gateway prototype. The paper concludes by outlining future research challenges by discussing the limitations of the selected scenarios related to configuration, deployment and scalability.