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- Metrics are important for the server, NMIS would use Reachability, Availability and Health to represent the network.
Reachability being the pingability of device,
Availability being (in the context of network gear) the interfaces which should be up, being up or not, e.g. interfaces which are "no shutdown" (ifAdminStatus = up) should be up, so a device with 10 interfaces of ifAdminStatus = up and ifOperStatus = up for 9 interfaces, the device would be 90% available.
Health is a composite metric, made up of many things depending on the device, router, CPU, memory. Something interesting here is that part of the health is made up of an inverse of interface utilisation, so an interface which has no utilisation will have a high health component, an interface which is highly utilised will reduce that metric. So the health is a reflection of load on the device, and will be very dynamic.
The overall metric of a device is a composite metric made up of weighted values of the other metrics being collected. The formula for this is based is configurable, so you can have weight Reachability to be higher than it currently is, or lower, your choice.
For more references go to NMIS Metrics, Reachability, Availability and Health
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You will be able to visualize device graphs with gaps, this is an example of how to recognize this behavior.
NMIS Polling Summary (menú: System > Host Diagnostics> NMIS Polling Summary)
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