ou may have heard the IoT loosely described as ‘an array of edge sensor and actuator devices, connected via the Internet to cloud-based computing and analytics resources’. This description works well enough for the Big Picture – but zoom in more closely, and you’ll find that it’s sometimes not entirely accurate.
The issue lies with the IoT’s edge devices. There are very large numbers of them, and their population is growing rapidly. However, not all are connected directly to the Internet. It’s not always possible or even desirable to do so.
First, let’s consider some near-future forecasts. According to a Juniper report , the number of IoT-connected devices, sensors and actuators will reach over 46 billion in 2021; compared with a United States Census Bureau world population estimate of just over 7.7 billion for 2021, this equates to very nearly six devices per capita.
These are large volumes, and would represent a considerable number of internet connections if they were all connected to the Internet. However, as mentioned, not all IoT devices are directly connected. Typically, an array of devices in a home or factory area will communicate via a non-IP bus such as ZigBee to a router – and the router alone will maintain the edge’s presence on the internet, allowing communication with the system’s remote cloud server. As we shall see, some devices, particularly small sensors, benefit from eliminating the overhead of a high-performance IP-based network. Additionally, the presence of an IP address increases a device’s vulnerability to hacking.