Have you ever thought that when you hold a TV remote and want to use it, what is one thing that you must have? That is you have to necessarily point your control at the device. This one-way, line-of-sight, short-range communication uses infrared (IR) sensors to enable communication and control and it is possible to operate TV remotely only with its control unit.
Now, picture a home with entertainment units, security systems including fire alarm, smoke detector and burglar alarm, air-conditioners and kitchen appliances all within whispering distance from each other and imagine a single unit that talks with all the devices, no longer depending on line-of-sight, and trainsffic no longer being one-way.
This means that the devices and the control unit would all need a common standard to enable intelligible communication. ZigBee is such a standard for embedded systems.
ZigBee is a wireless networking protocol specifically designed for Internet of Things(IOT). It is a low power, low cost consuming network protocol ideal for sensor to sensor communication.
Zigbee is the wireless technology which connects the devices in zigzag manner like bee. ZigBee is a wireless technology developed as an open global standard to address the unique needs of low-cost, low-power wireless M2M networks. The ZigBee standard operates on the IEEE 802.15.4 physical radio specification and operates in unlicensed bands including 2.4 GHz, 900 MHz and 868 MHz.