Intel® NetStructure™ MPCHC5525 System Master Processor Board IPMI Reference Driver User’s Guide 11
IBMU Functionality
2.1.4 Basic Communication Principles
The system management software communicates with the devices via the BMC. It can
communicate with:
•Boards/devices with IPMI controller
•Boards/devices without IPMI controller (nonintelligent devices)
•On-board se nsors
The following sections describe the basic communication procedure between the system
management software and the boards/devices given in the list above.
2.1.4.1 Boards/Devices with IPMI Controller
As seen in Figure1, the BMC contains SDRs of all sensors in the system. If the temperature
threshold value is exceeded on a board set as PM, the PM sends an eve nt mess age to the BMC. The
system management software can then trigger actions, for example, to incr ea se the fan speed.
2.1.4.2 Nonintelligent Devices
For nonintelligent devices, there are no SDRs in the SDR repository of the BMC. Since
nonintelligent devices have no IPMI controller , they do not send event messages. For this reason,
the system management software must regularly request sensor data (e.g., temperature) and check
whether the valu e has exceeded the normal range.
2.1.4.3 On-Board Temperature Sensor
The on-board temperature sensor is connected to the IPMI controller; therefore, there is also an
SDR for this sensor in the BMC’s SDR repository. If, for example, the temperature thr es hold value
is exceeded, the IPMI controller sends an event message to the BMC. The system management
software can then trigger actions, for example, to increase the fan speed.
2.1.5 Requirements
2.1.5.1 Boards/Devices with IPMI Controller and On-Board Sensors
For communication between system management software and IPMI controller devices or on-
board sensors, the following components are necessary:
•SDRs – For each sensor at ta ch e d to an IPMI controller an SD R mus t be av ai la ble
•IPMI driver for operating system
•Middleware
•System management software