Motorola PTP 400 Series - Manual (Page 132)

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8.3.14 Diagnostics
Link performance data is stored as a set of cascaded histograms:
• Histogram 1: the last hour at a resolution of 1 second
• Histogram 2: the last day (24 hours) at a resolution of 1 minute
• Histogram 3: the last month (30 days) at a resolution of 1 hour
The histograms are linked together by cascading data from one to the next: As a histogram
fills up, the data overflow is used as input to the next histogram in the chain.
For example, raw data is collected at a 1 second resolution and stored in Histogram 1.
Once Histogram 1 fills up, every minute the oldest minute of data (i.e. the 60 oldest seconds)
are analyzed and removed from the histogram (to make room for new data). The maximum,
minimum and mean values are computed and inserted as the next data set in Histogram 2.
Once Histogram 2 fills up, every hour the oldest hour of data (i.e. the 60 oldest minutes) are
analyzed and removed from the histogram (to make room for new data). The maximum,
minimum and mean values are computed and inserted as the next data set in Histogram 3.
Once Histogram 3 fills up, every hour the oldest hour of data is discarded.