Zigbee is a wireless networking standard that uses low power digital radio signals to connect devices together wirelessly. It operates in the 2.4GHz, 915MHz, and 868MHz frequency bands. Zigbee networks can include full-function devices, reduced-function devices, and coordinators that route data. Devices communicate using the CSMA-CA channel access method to check for clear channels before transmitting data. Zigbee provides low power consumption, low data rates, and high security making it suitable for applications like home automation and sensor networks.