The internet of thing (IOT) is the inter-connected of physical devices such as power plug, temperature sensors. These devices attached network module (Wifi, 3G or 4G) can extend the connectivity to internet. A bidirectional communication can be established once the device connected.
The devices can push the data to web and we can send control commands to the devices. Sensor network, Home Automation, and Smart Cities are the use cases in IOT industry.
There are some protocols like ZigBee, MQTT also related to IOT segment. Raspberry Pi, Aurdio, NXP and dragon-board boards can be used for prototype or development.