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We can also define the IoT as a network of connected devices, which have embedded and/or equipped with technologies that enable them to perceive, aggregate, and communicate meaningful information about the environment in which they are placed in, and/or themselves. The key characteristics of IoT from a broad‐view perspective are as follows:

 Unique Identity: As mentioned above, IoT is a network of connected devices with unique identifiers. It should be noted, however, that not all IoT devices are directly connected to the Internet. It is not always possible or even desirable to do so. In fact, a good number of IoT devices in a smart home or a factory setting communicate via a non‐IP link such as ZigBee or low‐power wide‐area network (LoRaWAN), which enables these devices to communicate over distances with gateways that interface to standard IP networks. It should also be noted that when such devices use IP, it does not by default mean they are using the public Internet. There could be home and enterprise networks that use IP with data traffic that may never touch the public Internet. Also, even if there is a cluster of non‐IP devices communicating with an aggregation gateway, beyond that gateway, the expectation is that the traffic will be IP‐based. Hence, all the “nodes” of the IoT are expected to create some sort of IP traffic, whether directly, or through some gateway.

 Sensing and Actuating: Sensors and actuators are two crucial elements in IoT systems. Sensors are used to perceive and gather information about some dynamic activity (pressure, temperature, altitude, etc.). The collected information is resulted from the interaction of the sensor with the environment.

 A more general expression for a sensor is a transducer. A transducer is any device that converts one form of energy into another. A microphone, for instance, is a transducer that takes sound energy and converts it to electrical energy in a useful manner for other components in the system to correlate with.

 An actuator is another type of transducer that is found in the majority of IoT systems. Actuators operate in the reverse manner as sensors. They typically take a form of energy and convert it into a physical action. For example, a speaker takes an electrical signal and converts it into a diaphragm vibration which replicates an audio signal.

 Connectivity, Communication, and Data Distribution: IoT devices are connected to the Internet either directly or through another device (gateway) where network connections are used for transporting data and interacting with users. Also, these devices allow users to access information and/or control devices remotely using a variety of communication protocols and technologies.

 Automation: Regardless of the application, most IoT devices are about automation, such as in industrial automation, business process automation, or home automation. Thus, such devices can generate, exchange, and produce data with minimal or no human intervention.

 Intelligence: Intelligence in IoT lies in the knowledge extraction from the generated data and the smart utilization of this knowledge to solve a challenge, automate a process, or improve a situation. There is no real IoT benefit without artificial intelligence, machine learning, Big Data² analytics, and cognitive algorithms.

Figure 1.1 depicts the abovementioned IoT characteristics.