Connectivity Framework
4: Connectivity Framework Layer
For IIoT systems, a connectivity framework should effectively handle an increasing number of data objects as more memory resources are added, and should support data objects of varying sizes.
4.2.4.2 APPS
IIoT systems comprise independently developed applications, each with evolving interfaces and data formats that should continue to interoperate with older versions of that interface. Forcing all apps to coordinate their update simultaneously to a new interface and data format version is unrealistic; there needs to be version negotiation between components. Interacting teams need tools, processes and eventually architectural support to solve the system-integration problem.
Data-centric connectivity frameworks allow applications to control data-oriented interfaces directly. Applications interact with shared data objects described by explicitly defined data types. Differences in data-oriented interfaces between apps can be automatically detected and adapted to match a participant’ s expectations, so as to decouple application interface dependencies and allow large projects to evolve interfaces and make parallel progress on multiple fronts.
For IIoT systems, a connectivity framework should support component interface evolution so that new capabilities can be added over time, without impacting the already existing components.
4.2.5 AVAILABILITY CONSIDERATIONS
4.2.5.1 REDUNDANCY
Failure of IIoT systems during operation can have fatal consequences. The system-relevant time period of continuous operation is dependent on the context of the system. For a power plant, the relevant time period could span years. For a medical imaging machine, the relevant time period could be only a few seconds.
But hosts and networks do fail, so redundant infrastructure( duplicate or triplicate or more) and failover mechanisms should be put in place. They rely on the connectivity infrastructure to communicate fault conditions and effect the appropriate state changes. To provide continuous system availability, a connectivity framework should support redundant endpoints and networks, and remove duplicate data transparently when the same update is received over multiple paths.
For IIoT systems, a connectivity framework should support continuous availability over a systemrelevant time period.
4.2.5.2 RECOVERY
An IIoT connectivity framework should be continuously available. It should not have single points of failure, and it should provide mechanisms for timely detection of system component failures. There should be mechanisms for component state durability and for state recovery and failover.
For IIoT systems, a connectivity framework should provide mechanisms for data durability and state recovery from fault conditions.
IIC: PUB: G5: V1.0: PB: 20170228- 36-