SOA at device level in the industrial domain: Assessment of OPC UA and DPWS specifications

Service-oriented Architecture (SOA) is increasingly relevant across several domains of application by promising systems openness and unification over a common design and communication paradigm. At device level, the application of SOA is carried, on one hand, by Devices Profile for Web Services (DPWS) and complementary web-based specifications oriented towards resource management, and, on the other hand, by OPC Unified Architecture (OPC UA) framework. These are currently the major candidates to be deployed at device level in a service-oriented industrial scenario. This document offers an overlook over both approaches, along with some complementary WS-* specifications through an extensive technical assessment. Also, it illustrates that neither one of these specifications can alone entirely cope with the requirements of service-oriented industrial domain device level and that a combined approach promises to deliver an important contribution. Synergies between the two sets of specifications for a more conformant solution are identified, and a convergence approach is enunciated in an era where it is imperative to avoid unnecessary layers of integration across enterprise infrastructure to ensure a more agile, lean and sustainable development.