Remote management of client computers often requires the managed computer to be turned on with an operating system running. When a computer is turned on with a running operating system, the computer is considered in-band.
Out-of-band is when a client computer is in one of the following out-of-band states:
The computer is plugged in but is not actively running (off, standby, hibernating).
The operating system is not loaded (software or boot failure).
The software-based management agent is not available.
Out-of-band management is the ability to manage computers in these states. Computers with Intel AMT, ASF, DASH, or IPMI capabilities can be managed out of band.