Technical Product Specification

Intel® Server System R2000LH2/T2 Product Family TPS Intel® Intelligent Power Node Manager (NM)
Revision 1.0
93
13.1.3
Role of BMC in NM
This section summarizes the BMC role in the NM feature implementation.
13.1.3.1
External Communications Link
The BMC provides the access point for remote commands from external management SW and
generates alerts to that SW. The ME plays the role of an IPMI satellite controller that
communicates to the BMC over a secondary IPMB. There are mechanisms to forward
commands to ME and send response back to originator. Similarly events generated by ME to
the BMC (via IPMB) have to be sent by the BMC to the external SW over the LAN link. It is the
responsibility of BMC to implement these mechanisms for communication with Node Manager
(NM).
This section provides an overview of how the external communication link to ME works. Refer to
the Intel
®
Intelligent Power Node Manager 2.0 External Architecture Specification using IPMI for
details of this interface.
13.1.3.1.1
Command Passing via BMC
External SW wishing to communicate with the NM will send bridged IPMI commands to BMC.
This will be in the form an IPMI packet encapsulated in another packet, following standard IPMI
bridging as described in the IPMI 2.0 Specification. BMC forwards the encapsulated command
to NM engine on the ME and returns the response to the sender.
Due to the fact that some of the NM commands have potential for performance limiting and
system shut-down, the BMC FW enforces an administrator privilege for any commands bridged
to the ME.
13.1.3.1.2
Alerting
Alerts may be sent from the NM in the ME to the external SW by one of two different methods
depending on the nature of the alert.
Alerts that signify fault conditions that should be recorded in the system SEL will be sent to the
BMC by the ME using the IPMI Platform Event Message command. The BMC deposits such
events into the SEL. The external SW must configure the BMC’s PEF and alerting features to
send that event out as an IPMI LAN alert, directed to the SW application over the LAN link.
Alerts that provide useful notification to the external SW for NM management, but do not
represent significant fault conditions that need to be put into the SEL, will be sent to the BMC
using the IPMI Alert Immediate command. This requires that the external SW application
provides the NM on the ME with the alert destination and alert string information needed to
properly form and send the alert. The external SW must first properly configure the alert
destination and string in the BMC LAN configuration using standard IPMI commands, then
provide the associated selectors to the BMC using the Set Node Manager Alert Destination
OEM command.
13.1.3.2
BIOS-BMC-ME Communication
Unlike the implementation in previous generation servers in which the BIOS and ME
communicated through the BMC, this generation of platforms the BIOS communicates directly
with the ME via PECI.