Down indicates that a system has failed. For example, Router Down indicates that a router has failed. A system failure causes all ports or interfaces on the system and all objects accessed through the system to be unreachable.
The events used as symptoms to diagnose Down vary. It depends on whether the system is connected to other systems by a physical or logical link. When a system is not connected to other systems, the event is system Unresponsive.
When a system is connected to one or more systems, the events used as symptoms to diagnose system Down include:
MightBeDown for the system itself and any connected systems.
DetectedProblemSymptomImported for any peer network adapter and any peer subinterfaces.