Learn in the textbookIoT Networks
DefinitionAn IoT area network (IoTエリアネットワーク) links IoT devices such as sensors within a limited space like a factory or a home, and connects them through an IoT gateway to the wide-area network and IoT servers outside.
ExplanationThe IoT gateway is the entry and exit point between traffic inside the area and the wide-area network outside, relaying data and converting its format. Inside the area, devices connect by short-range wireless such as ZigBee, and also by PLC, a wired method that uses the power lines carrying electricity as the communication path. With multi-hop (マルチホップ) relaying, where one device picks up another's signal and passes it on again and again, the network covers a wider area than any single device's signal can reach.
AnalogyThink of an apartment building: the rooms (devices) are joined by the building's wiring or wireless, and everyone goes in and out to the street through the front entrance (the gateway).
Memory hookThe "gate" in gateway is literally a gate: the one that separates the inside of the area from the outside.