Power cycling is the act of turning a piece of equipment, usually a computer, off and then on again. Reasons for power cycling include having an electronic device reinitialize its configuration or recover from an unresponsive state of its mission critical functionality, such as in a crash or hang situation. Power cycling can also be used to reset network activity inside a modem.
Power cycling can be done manually, usually using a switch on the device to be cycled; automatically, through some type of device, system, or network management monitoring and control; or by remote control; through a communication channel.
In the data center environment, remote control power cycling can usually be done through a Power distribution unit, over TCP/IP. In the home environment, this can be done through home automation powerline communications, via IP protocols (wired orwireless), or by phone line.
IT specialists sometimes satirically refer to power cycling as the "O.F.F.-O.N." test. ~ Wikipedia.org
