What is Intelligent Platform Management Interface ?

The Intelligent Platform Management Interface (IPMI) is a standardized computer system interface used by system administrators to manage a computer system and monitor its operation.

IPMI is a message-based, hardware-level interface specification: an IPMI sub-system operates independently of the operating system (OS) to allow administrators to manage a system remotely in the absence of an operating system or of the system management software, and thus can be used before an OS has booted (allowing e.g. BIOS settings to be remotely monitored or changed), when the system is powered down, or after OS or system failure, which is the key characteristic of IPMI compared with in-band system management by e.g. remote login such as SSH.

System administrators can use IPMI messaging to monitor platform status (e.g. system temperatures, voltages, fans, power supplies and chassis intrusion); to query inventory information; to review hardware logs of out-of-range conditions; or to perform recovery procedures such as issuing requests from a remote console through the same connections e.g. system power-down and rebooting, or configuring watchdog timers. The standard also defines an alerting mechanism for the system to send a simple network management protocol (SNMP) platform event trap (PET).

IPMI components

An IPMI sub-system consists of a main controller, called the baseboard management controller (BMC) and other management controllers distributed among different system modules that are referred to as satellite controllers. The satellite controllers within the same chassis connect to the BMC via the system interface called Intelligent Platform Management Bus/Bridge (IPMB) — an enhanced implementation of I²C (Inter-Integrated Circuit). The BMC connects to satellite controllers or another BMC in another chassis via the Intelligent Platform Management Controller (IPMC) bus or bridge. It may be managed with the Remote Management Control Protocol (RMCP), a specialized wire protocol defined by this specification. RMCP+ (a UDP-based protocol with stronger authentication than RMCP) is used for IPMI over LAN.

Interfaces to the baseboard management controller

The baseboard management controller (BMC) is the intelligence in the IPMI architecture. It is a specialized microcontroller embedded on the motherboard of a computer, generally a server. The BMC manages the interface between system management software and platform hardware.