User's Manual

8 Web Page Reference
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Set Date: Displays the current date. The year, month and day can be set using the drop-
down selection boxes.
Time Zone: See Section.8.3.11.9 “Setting the clock”.
Da
ylight Saving: See Section 8.3.11.9 “Setting the clock”
8.3.12
Diagnostics
To furthe
r enhance the diagnostic capabilities of the PTP 600 Series, the storage of link
performance histograms has been extended to 31. To optimize RAM (volatile memory) usage
a cascading histogram approach has been adopted. The root histogram is identical to the
histograms in earlier releases of the software, that is data is stored for one hour at a
resolution of one second. Previously, the histograms were simple cyclic buffers which never
stored more that the last one hour of data. The new cascading histogram approach daisy
chains multiple histograms together. When the first histogram fills up the overflow from the
first is used as an input to the next histogram in line. To optimize memory utilization, a
statistical analysis is performed on the overflow to reduce the amount of data to be stored. In
the case of the PTP 600 Series the cascading histograms are defined as:
• Histogram 1: 1 hour at a resolution of 1 second
• Histogram 2: 24 hours at a resolution of 1 minute
• Histogram 3: 30 Days at a resolution of 1 hour
For example, when histogram 1 fills up and starts to overflow the first minute of overflow is
analyzed and the maximum, minimum and mean over that minute are computed and inserted
into histogram 2. When histogram 2 fills up and starts to overflow the first hour of overflow is
analyzed and the maximum, minimum and mean over that hour is computed and inserted into
histogram 3. When histogram 3 starts to overflow, the overflow data is simply discarded.