Out-of-band Management

In computing, out-of-band management (sometimes called lights-out management or LOM) involves the use of a dedicated management channel for device maintenance. It allows a system administrator to monitor and manage servers and other network equipment by remote control regardless of whether the machine is powered on, or if an operating system is installed or functional.

By contrast, in-band management like VNC or SSH is based on software that must be installed on the remote system being managed and only works after the operating system has been booted. This solution may be cheaper, but it does not allow access to BIOS settings, or the reinstallation of the operating system and cannot be used to fix problems that prevent the system from booting.

Both in-band and out-of-band management is usually done through the network connection, but an out-of-band management card can use a physically separated network connector if preferred. A remote management card usually has an at least partially independent power supply, and can power the main machine on and off through the network.

This article focuses mainly on out-of-band (OOB) management of servers, but also high-end network devices sometimes offer out-of-band management. Modular/blade systems with dedicated management modules often offer a dedicated OOB ethernet port or Lights out management port. Some 'top of rack' switches also offer this functionality.