1.1. IPMI IMPLEMENTATION
Figure 1.2: Parts of a Management Controller
interface to all the sensors, events, and Field Replacable Unit (FRU) data in the system.
Figure 1.2 shows the various parts of the management controller. Note that most everything is optional; depending on what a management controller does it may only need some things. The Baseboard Management Controller (BMC) is required to have a lot of the items.
The MC Processor is generally a small, inexpensive, but reliable microcontroller. Several companies sell processors that have a lot of the IPMI components already implemented and software to help a company implement IPMI on their system.
The system interface provides a way for the main processor to communicate with the management controller. Some systems do not have this connection and only use external interfaces and/or Intelligent Platform Management Bus (IPMB) interfaces. System interfaces include SMIC, KCS, and BT interfaces.
An MC (generally the BMC) may have other interfaces to an external management system through serial ports or Ethernet.
Generally, sensors sit on an I2C bus since many off-the-shelf sensors can sit directly on the bus with no extra logic. Wherever the sensors sit, the MC provides a more abstract interface to the sensors so that the management system does not have to know the details of how to talk to the sensor. Sensors may be traditional analog sensors like temperature and voltage. But they may report other things, too, like the