System Architecture Design

pSHIELDSystem Architecture DesignPUA functional component describes a functional entity that, in general, does not have necessarily a physicalcounterpart (e.g. a software functionality, a middleware service, an abstract object, etc.). A physicalcomponent describes an entity that can be mapped into a physical object (e.g. a hardware component). Afunctional component, as well as a physical component, can require or provide functionalities, properties,connections, services, configuration parameters, energy, etc. To model these aspects, we use theinterface symbol. An interface can be used to import all the needed elements to make a component toproperly work. An interface can also be used to export some elements as outcome of the componentoperations or physical structure.From the pSHIELD perspective, there exist three different types of Embedded System Devices (ESDs):Legacy Embedded System Device (L-ESD): it represents an individual, atomic physical EmbeddedSystem device characterized by legacy Node, Network and Middleware functionalities. This device can bemodelled as depicted in the following figure. So, the legacy functionalities of an L-ESD can be partitionedinto three subsets:− Node layer functionalities: hardware functionalities such as processors, memory, battery, I/Ointerfaces, peripherals, etc.−Network layer functionalities: communication functionalities such as connectivity, protocol stacks,etc.− Middleware layer functionalities: firmware and software functionalities such as services,functionalities, interfaces, protocols, etc.The L-ESD exposes three interfaces: (i) the legacy, technology-dependent middleware services, (ii) thelegacy, technology-dependent network services and (iii) the legacy, technology-dependent nodecapabilities.pSHIELD Embedded System Device (pS-ESD): is a L-ESD equipped at least with the minimal set ofpSHIELD functionalities at Middleware Layer. This device can be modelled as depicted in the second ofthe following figures: The pS-ESD exposes the same functionalities as the L-ESD plus an additionalinterface: the pSHIELD Middleware layer services.pSHIELD SPD Embedded System Device (pS-SPD-ESD): is a pS-ESD equipped at least with theminimal set of pSHIELD Overlay functionalities. This device can be modelled as depicted in the third ofthe following figures.The pS-SPD-ESD exposes the same functionalities as the pS-ESD plus an additional interface: thepSHIELD Overlay layer SPD services provided by a so-called Service Agent operating in that ESD.PUD2.3.2Issue 5 Page 108 of 122