The System Monitor lets you:
Use the System Monitor in addition to the Control Panel to monitor the R/3 System.
The System Monitor displays the instances of your R/3 System as icons in a network graphic. The status of each instance is indicated by different colors. For example, if a system is not running, this is shown in the graphic in red.

See also:
Calling the System Monitor System Monitor Display Operation Modes and the System Monitor Monitors in the CCMS