Host Embedded Controller Interface
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Host Embedded Controller Interface (HECI) is technology introduced in 2006 used for Active Management Technology (
Details
The HECI bus allows the host operating system (OS) to communicate directly with the Management Engine (ME) integrated in the chipset. This bi-directional, variable data-rate bus enables the host and ME to communicate system management information and events in a standards-compliant way, essentially replacing the System Management Bus (SMBus). The bus consists of four wires: a request and grant pair along with a serial transmit and receive data pair.
Original equipment manufacturers (
HECI and the previously used SMBus have the following aspects in common: the Host OS is able to control system management devices such as: on-board fan controllers, remote wake devices such as
Host-Initiated Messages
- Read battery status
- Read thermal data
- Enable/disable wake devices
- Notify devices to change power state (thermal, performance, or power throttling)
Management Engine-Initiated Messages
- Alert Host to battery event
- Low or Critical battery level
- Switch between A/C (wall socket power) and D/C (battery)
- Alert Host to thermal event (Hot or Critical thermal trip)
- Change Fan Speed
- Detect network wake
- Boot/Shutdown System
- Detected Host Intrusion
- Change boot device
- Report system inventory
Example
As an example, assume the case of Wake-on-LAN. Traditionally, the OS controls Wake-on-LAN and must call
When the magic wake packet is received by the LAN device, the encapsulated data is passed to the ME, which has its own TCP/IP stack and can decapsulate the packet. The ME then asserts its request line (REQ#), the host acknowledges by asserting grant (GNT#), and the message is passed to the host to initiate a wake event.
With this technology, the magic packet may be encapsulated in TCP packets thus allowing the packet to traverse network infrastructures via routers and thereby increasing the attack surface, something which traditional Wake-on-LAN does not enable. An advantage in Intel-centric deployments is that the solution does not require non-Intel drivers. If no host/ME interaction is needed, HECI and other ME technologies are OS independent.
See also
- Intel Active Management Technology (AMT)
- Baseboard management controller(BMC)
- Platform Environment Control Interface (PECI)
Sources
- Hofemeier, Gael. "Intel Software Network Blogs >>Intel(r) AMT and the Intel(r) ME". Retrieved 2011-12-14.
- Mungara, Ajay. "Intel Software Network Blogs >> Let us talk about HECI and LMS". Retrieved 2007-12-29.
- "Open Source Intel Active Management Technology Drivers and Tools". Retrieved 2007-12-29.
- "Intel Active Management Technology". Retrieved 2007-12-29.
- "Intel Software Network Blogs >> Baseboard Management Controllers (BMC) vs Virtualization Appliance-Based Management". Archived from the original on 2011-08-13. Retrieved 2007-12-29.