Internet of Things – Architecture © - 90 -
order to support global manageability, interoperability, and scalability,
this aspect needs to provide a common communication paradigm for
every possible networking solution. This is the narrow waist for the
Internet of Things. The difference between identifiers (unique descriptors
of the Digital Artefact; either active or passive), and locators (descriptors
of the position of a given IoT element in the network), is the first
convergence point in the IoT Communication Model. Thus, this
interoperability aspect is in charge of making any two systems
addressable from one another notwithstanding the particular
technologies they are adopting. In the case of our recurring example the
AndroidApp must be able to receive alarms generated by the alarm
Service, which in turns, must receive information from the Mote Runner
Device: in order for this to be possible the system must ensure that the
correct identifiers are supported by all the communicating technologies or
can be resolved via appropriate methods; End-to-end aspect: this aspect takes care of reliability, transport issues,
translation functionalities, proxies/gateways support and parameter
configuration when the communication crosses different networking
environments. By providing additional interoperability aspects on top of
those of the Network and ID aspect, this aspect provides the final
component for achieving a global M2M communication model.
Connections are also part of the end-to-end scope. Also, Application
Layer aspects are taken care of here. Moreover Application Protocols in
the IoT tend to embed confirmation messages, and congestion control
techniques require being more complex than what is achievable in the
Transport Layer in the legacy models. With reference to the recurring
example, this aspect will take care of modelling the overall
communication between the Alarm Service and the Mote Runner Node
and between the AndroidApp and the Alarm Service; Data aspect: the topmost aspect of the IoT Communication Model is
related to data definitions and transfers. While the Information Model
provides a high-level description for data of IoT systems, the purpose of
this aspect is to model data exchange between any two actors in the IoT.
As described in the IoT Information Model (See Section 3.4), data
exchanged in IoT can adopt many different representations, ranging from
raw data to complex structures where meta-information is added to
provide context specific links. Finally, to make this possible, the data
aspect needs to model the following characteristics [Rossi 2013]:- Capability of providing structured attributes for data description;
- Capability of being translated (possibly by compression
/decompression) the one to each other, e.g. CoAP is a