(Intelligent Platform Management Interface) A protocol for monitoring server hardware for temperature, voltage, chassis intrusion, etc. Introduced in 1998 by Intel, HP, NEC and Dell, IPMI defines a standard set of messages for the characteristics of hardware components. Sensors funnel data into a Baseboard Management Controller (BMC), which sends IPMI messages over the server's system bus to the network as well as over an independent, internal Platform Management Bus (IPMB).

Intelligent Platform Management Bus (IPMB)
The IPMB is an I2C-based bus that resides inside the server cabinet. It provides out-of-band communications in case of server failure, which could render the server's system bus inoperable. The IPMB can connect externally via the ICMB bus.

Intelligent Chassis Management Bus (ICMB)
The ICMB is used to connect the IPMI server to the outside world. Signals can be transported over an I2C bus, a CAN bus or via RS-485 connections. See I2C bus, RS-485 and CAN bus.