Out-of-band management
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In systems management, out-of-band management (OOB; also lights-out management or LOM) is a process for accessing and managing devices and infrastructure at remote locations through a separate management plane from the production network. OOB allows a system administrator to monitor and manage servers and other network-attached equipment by remote control regardless of whether the machine is powered on or whether an OS is installed or functional. It is contrasted to in-band management which requires the managed systems to be powered on and available over their operating system's networking facilities.
OOB can use dedicated management interfaces, serial ports, or cellular 4G and 5G networks for connectivity.
Out-of-band management is now considered an essential network component to ensure business continuity and many manufacturers have it as a product offering.
Out-of-band versus in-band
By contrast, in-band management through VNC or SSH is based on in-band connectivity (the usual network channel). It typically requires software that must be installed on the remote system being managed and only works after the operating system has been booted and networking is brought up. It does not allow management of remote network components independently of the current status of other network components. A classic example of this limitation is when a sysadmin attempts to reconfigure the network on a remote machine only to find themselves locked out and unable to fix the problem without physically going to the machine. Despite these limitations, in-band solutions are still common because they are simpler and much lower-cost.
Design
A complete remote management system allows remote reboot, shutdown, powering on; hardware sensor monitoring (fan speed, power voltages, chassis intrusion, etc.); broadcasting of video output to remote terminals and receiving of input from remote keyboard and mouse (
As management via serial port has traditionally been important on servers, a complete remote management system also allows interfacing with the server through a serial over LAN cable.
As sending monitor output through the network is bandwidth intensive, cards like AMI's
The remote system can be accessed either through an
There are also various scaled-down versions, up to devices that only allow remote reboot by power cycling the server. This helps if the operating system hangs, but only needs a reboot to recover.
An older version of out-of-band management is a layout involving the availability of a separate network that allows network administrators to get command-line interface access over the
If a location has several network devices, a
Implementation
Remote management can be enabled on many computers (not necessarily only servers) by adding a remote management card (while some cards only support a limited list of motherboards). Newer server motherboards often have built-in remote management and need no separate management card.
Internally,
Both in-band and out-of-band management are usually done through a network connection, but an out-of-band management card can use a physically separated network connector if preferred. A remote management card usually has at least a partially independent power supply and can switch the main machine on and off through the network. Because a special device is required for each machine, out-of-band management can be much more expensive.
Serial consoles are an in-between case: they are technically OOB as they do not require the primary network to be functioning for remote administration. However, without special hardware, a serial console cannot configure the UEFI (or BIOS) settings, reinstall the operating system remotely, or fix problems that prevent the system from booting.
See also
- Cisco IMC – Out-of-band management platform by Cisco
- Dell DRAC – Out-of-band management platform by Dell
- Desktop and mobile Architecture for System Hardware – Protocol standard for out-of-band management
- Intel Active Management Technology – Out-of-band management platform by Intel
- HP Integrated Lights-Out – Out-of-band management platform by HP
- IBM Remote Supervisor Adapter – Full-length ISA or PCI adapter by IBM
- LOM port – Out-of-band management platform by Sun Microsystems
- Management Component Transport Protocol – Low-level protocol used for controlling hardware components
- Opengear – Company that manufactures out-of-band management systems
- Perle Systems – Manufacturer of device networking hardware
References
- ^ "On-board IPMI BMC specification". Super Micro Computer. Retrieved 2014-02-21.
- ^ "American Megatrends MegaRAC G4 user's guide" (PDF). American Megatrends. p. 1. Retrieved 2020-07-10.
- ^ "features embedded VNC® for remote control at Intel Developer Forum". RealVNC. 2011-09-02. Retrieved 2014-02-21.
- ^ Oracle Integrated Lights Out Manager
- ^ "Intel Ethernet Controller I210 Datasheet" (PDF). Intel. 2013. pp. 1, 15, 52, 621–776. Retrieved 2013-11-09.