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Industrial Ethernet Book 99

Technology The OpenFog RA description is a composite of perspectives and multiple stakeholder views used to satisfy a given fog computing deployment or scenario. The OpenFog Reference Architecture is a 162-page document that features an abstract architectural description, providing an in-depth look at the full OpenFog RA. How fog computing works Fog computing solves performance challenges in advanced digital deployments in IoT, 5G and artificial intelligence. These include the control of performance, latency and network efficiency. It’s important to note that cloud and fog computing are on a mutually beneficial, inter-dependent continuum. Fog does not replace the cloud; it works with cloud to enable the requirements of selected use cases. Certain functions are naturally more advantageous to carry out in fog nodes, while others are better suited to cloud. The traditional backend cloud will continue to remain an important part of computing systems as fog computing emerges. To illustrate how fog computing works, consider an oil pipeline with pressure and flow sensors and control valves. One could transport its sensor readings to the cloud (i.e. using expensive satellite links), analyze the readings in cloud servers to detect abnormal conditions, and send commands back to adjust the positon of the valves. However, the bandwidth to transport the sensor and actuator data to and from the cloud could cost thousands of dollars per month; those connections could be susceptible to hackers; it may take several hundred milliseconds to react to an abnormal sensor reading, during which time a major leak could spill significant oil; and if the connection to the cloud is down or the cloud is overloaded, control is lost. In that same scenario, if a hierarchy of local fog nodes is placed near the pipeline, they can connect to sensors and actuators with inexpensive local networking facilities. Fog nodes can add extra security controls, lessening the hacker threat. Fog nodes can react to abnormal conditions in milliseconds, quickly closing valves to greatly reduce the severity of spills. This example illustrates the advantages of local control in the fog nodes to produce a more robust control system. Moving most of the decision-making functions of this control system to the fog, and only contacting the cloud occasionally to report status or receive commands, creates a superior control system. The OpenFog RA describes a generic fog platform that is designed to be applicable to any vertical market or application. This architecture is applicable across many different markets including, but not limited to, transportation, agriculture, smart-cities, smart–buildings, healthcare, hospitality, energy and financial services. It provides business value for IoT applications that require real-time decision making, low latency, improved security, and are networkconstrained. Pillars of OpenFog architecture The OpenFog RA is driven by a set of core principles called pillars. These pillars, depicted in the above figure, form the principals, approach and intention that guided the definition of the reference architecture. They represent the key attributes that a system needs to embody the OpenFog definition of a horizontal, system-level architecture that provides the distribution of computing, storage, control, and networking functions closer to the data source (users, things, etc.) along the cloud-to-thing continuum. Architecture description The OpenFog RA description is a composite of perspectives and multiple stakeholder views used to satisfy a given fog computing deployment or scenario. Before going into the lower level details of the view, it is important to first look at the composite architecture description, depicted in the figure above. The abstract architecture includes perspectives, shown in grey vertical bars on the sides of the architectural description. The perspectives include: Performance: Low latency is one of the driving reasons to adopt fog architectures. There are multiple requirements and design considerations across multiple stakeholders to ensure this is satisfied. This includes time critical computing, time sensitive networking, network time protocols, etc. It is a cross cutting concern because it has system and deployment scenario impacts. Security: End-to-end security is critical to the success of all fog computing deployment scenarios. If the underlying silicon is secure, but the upper layer software has security issues (and vice versa) the solution is not SOURCE: OPENFOG CONSORTIUM 25 4.2017 industrial ethernet book


Industrial Ethernet Book 99
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