Page 22 - U4SSC Data and API requirements for centralized smart city platforms

Figure 7: The concept of the SC Hub

More specifically, the SC Hub should offer standardized APIs for data flow management and
interworking with SCP (e.g., in an analogous manner like network slots in a network hub) to: the
IoT local owners; the local public and private service providers; the remote service providers
(e.g., distant cloud-based services); and the local stakeholders and utility systems. As such, all
these partners should comply with the specification rules of the SC Hub and submit data under
predefined formats. They could also use specific, open SDK when it is needed to develop compatible
information and service flows. The SC Hub consists of layers – like those defined by the Open
Systems Interconnection model (OSI model) (ISO, 1994) for the typical network hub – that will
enable data flow within the SC Hub and between the APIs, which are analysed in the following
sections. Moreover, the SC Hub will not necessarily perform data operations (processing, storage,
and wrangling) like the digital hub (Figure 6) does, but only transmits data.

4.1 Connecting the data sources: the SC Hub’s architecture

The SCHub architecture is inspired by an IoT architecture, whose main components have been
discussed extensively in (Fremantle et al., 2015; Ray, 2016; Fahmideh and Zowgi, 2020). Their
application in the SCHub concept, however, needs special attention to address the specific needs
of the SC deployment environment and scale. More specifically, the SCHub reference architecture
must tackle the following parameters:

Generality: the SCHub reference architecture must be general enough to be able to accommodate
current and future needs for integration of devices and services.

Applicability: the SCHub reference architecture must be applicable at city scale. This allows the
optimization of the reference architecture by not including components and services that are
needed in different deployment levels. At the same time, this makes it easier to make the design
decision necessary to optimize this type of deployment

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