Models the NIST Framework for Improving Critical Infrastructure Cybersecurity This notice refers only to the SABSA EA Models of NIST CSF and not the NIST CSF itself, which is freely available at https://doi.org/10.6028/NIST.CSWP.04162018; These models are shared in accordance with the terms of the Open Source Licence published at https://sabsa.org/open-source-licence. The format (but not the content of this Model- including that accompanying this limited open source licence) made available by the Institute (as defined hereafter) (the Model) is © 2021, The SABSA Institute C.I.C (a registered community interest company in England under registration number 08439587) (the Institute). One great example of architecture frameworks applications for service systems, the “High Level Reference Model for the Smart Grid,” developed by NIST in 2010 under the “Energy Independence and Security Act of 2007” (EISA),is presented below: EISA designated the development of a Smart Grid as a national policy goal, specifying that an interoperability framework should be “flexible, uniform and technology neutral. The law also instructed that the framework should accommodate “traditional, centralized generation and distribution resources” while also facilitating incorporation of new, innovative Smart Grid technologies, such as distributed renewable energy resources and energy storage. (NIST 2010) The NIST reference model was developed as “a tool for identifying the standards and protocols needed to ensure interoperability and cyber security, and defining and developing architectures for systems and subsystems within the smart grid." Figure 1 illustrates this model and the strategic (organizational), informational (business operations, data structures, and information exchanges required among system entities), and technical needs of the smart grid (data structures, entities specifications, interoperability requirements, etc.).