System Architecture Design

pSHIELDSystem Architecture DesignPUApplication ScenariopSHIELD Middleware LayerLegacy MiddlewareCapabilitiespSHIELD Middleware AdapterCore SPD ServicesandInnovative SPD FunctionalitiesSensed MetadataElaborated MetadataRules for discoveryand compositionSemanticKnowledgeRepositoryControl algorithmsHeterogeneous SPD‐relevantparameters and measurementsSPD Security AgentCommands for composition andconfiguration of SPD modulesExchangedmetadatapSHIELD Node LayerpSHIELD Node AdapterInnovative SPDFunctionalitiespSHIELD Network LayerpSHIELD Network AdapterInnovative SPDFunctionalitiesOther SPD SecurityAgentsLegacy NodeCapabilitiesLegacy NetworkCapabilitiespSHIELD OverlayLayerFigure 11 – pSHIELD Middleware layer.Given an application scenario, the pSHIELD Middleware layer is in charge to get heterogeneous SPDrelevantparameters and measurements from the Node and Network layer adapters. This information,jointly with the ones gathered from the Middleware layer, are semantically enriched and sent to theOverlay layer as sensed metadata. Once the Overlay layer elaborates these information as inputs ofproper control algorithms, it sends back to the Middleware layer the best rules to discover and composethe available SPD middleware, network and node resources. Indeed the discovery and compositionservices are part of the Core SPD Services provided by the pSHIELD Middleware layer. The Core SPDServices are detailed in the following section. Once activated, the Core SPD Services elaborate theproper commands and configuration to compose the available legacy Middleware, Network and Nodelayer capabilities as well as their innovative SPD functionalities.Given an application scenario, it is possible to identify a legacy Middleware layer (e.g., CORBA, DCOM,etc.), composed by several Legacy Middleware Capabilities (e.g., remote procedure call, messagingqueues, etc.). To be pSHIELD compliant, a Middleware layer must have a pSHIELD Middleware adapter,providing a mandatory set of Core SPD Services (i.e., discovery, composition, orchestration) and anoptional set of innovative SPD functionalities (e.g., identification, authentication, auditing, accounting, antitampering,etc.).3.4.1 SPD Driven SemanticsIn order to cope with the intrinsic Embedded Systems complexity and heterogeneity the proposed solutionis to design and implement a proper abstract, comprehensive semantic model able to provide ahomogeneous representation of heterogeneous SPD-related parameters and conceptual models. So thePUD2.3.2Issue 5 Page 42 of 122