The Last-Value Threshold is meant to detect spikes in network usage. By default, this is set to 90%. If 90% of the interface's bandwidth capabilities are reached, it will then check the average bandwidth usage on the interface within the time period specified (default is 915 seconds). If the average exceeds the Short-Term Value threshold (default is 70%), the Monitor fails. If the average is not exceeded, the Monitor succeeds.
This behavior is basically to avoid getting alerted every time a short network spike occurs.
Hopefully this helps answer your question.
Chris Foley | Support Specialist
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