A baseboard management controller (BMC) is a specialized service processor that monitors the physical state of a computer, network server or other hardware device using sensors and communicating with the system administrator through an independent connection. The BMC is part of the Intelligent Platform Management Interface (IPMI) and is usually contained in the motherboard or main circuit board of the device to be monitored.
The sensors of a BMC measure internal physical variables such as temperature, humidity, power-supply voltage, fan speeds, communications parameters and operating system (OS) functions. If any of these variables happens to stray outside specified limits, the administrator is notified. That person can then take corrective action by remote control. The monitored device can be power cycled or rebooted as necessary. In this way, a single administrator can remotely manage numerous servers and other devices simultaneously, saving on the overall operating cost of the network and helping to ensure its reliability.