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Comment: According to the RAMI 4.0 architecture, the “standard” way for Industrie 4.0 platforms to integrate legacy equipment (or any other kind of legacy “object”, including software components) into will be to encapsulate them inside an ad-hoc Administration Shell wrapper, which will expose them as I4.0 Components. The I4.0 interface specification has not been published yet, but a key enabling technology will probably be OPC UA, used as both a communication protocol and a data meta-model. In FAR-EDGE, OPC UA will be one of the field communication technology supported.
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Comment: Relevant architectures for FAR-EDGE are Platform Industrie 4.0 (RAMI 4.0), Industrial Internet Consortium (IIRA), OpenFog Consortium (OpenFog RA). We will use the 3D coordinate system from RAMI 4.0 to map the elements of the FAR-EDGE Platform to concepts that are commonly understood and agreed on within the Industrie 4.0 community. We are also taking care that the FAR-EDGE Platform implementation will be compatible with future Industrie 4.0 compliant equipment – in particular I4.0 Components – by supporting OPC UA as the main protocol for field communication. Regarding IIRA and OpenFog RA, in the FAR-EDGE RA we are adopting a key architectural pattern included in both of them (with different names): a layered approach that leverages peer-to-peer communication in each layer to decentralize control. The most visible trait of the FAR-EDGE reference architecture is its partitioning into horizontal layers having different scopes – i.e., in bottom-up order: Fog (field, shopfloor), Edge (plant), Cloud (enterprise, supply chain). This pattern in inspired from a similar one in IIRA, called Layered Databus. However, in FAR-EDGE there is no “databus” included in each layer, but rather an additional layer called the Ledger, positioned between the Edge and the Cloud ones. Its role is to coordinate the execution of distributed processes running on Edge Gateways. The horizontal partitioning of the RA is driven by technical concerns (e.g., where software components are deployed, who are the stakeholders of their implementation). There is also a vertical partitioning, though, which is orthogonal to the horizontal one. This is a high-level functional decomposition which identifies three functional scopes: Automation, Virtualization and Analytics (more on that in the API section below).