Actual and derived state
Each in a service model has an actual state and a derived state.
A device element's actual state is determined by events that occur on the device, regardless of the service models in which it participates. A service model member's actual state is generated from the service model in its own service context. The element's derived state is generated from policy propagation within a given context. In the Service Impact graph, the symbol that appears inside the node's border reflects the actual state; the border that outlines the node reflects the derived state.
In the following example graph, the actual and derived states are down. The parents of the device have a degraded and at-risk actual state, yet the derived state based on the contextual policy, is degraded.
Visual state indicators
Availability | Performance | Symbol / Actual State | Border / Derived State |
---|---|---|---|
UP | ACCEPTABLE | ![]() |
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ATRISK | Not applicable. | ![]() |
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DEGRADED | DEGRADED | ![]() |
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DOWN | UNACCEPTABLE | ![]() |
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A member's actual and derived states can be different. As shown in the following example, a service's actual state can be up, but an applied context policy changed its derived state to down.