Users Guide

Traffic Flow Portlet | Traffic Flow Analyzer
OMNM 6.5.3 User Guide 537
example, Last 8 Hours, Last 120 Minutes, Last 45 Days, etc. If Absolute is selected, you must
enter an absolute start and end time. Click Apply for these settings to take effect.
Data for Last 15 Minutes shows minute-by-minute data and this type of data typically appears
after about 2-5 minutes of collection (after the exporter is first registered and flow packets are
received from this device). Data for Last 24 Hours shows hourly data by default, and this type
of aggregate data is computed after each hour has passed. For example, aggregate data for
9:00 AM will only be computed after the 9:00 hour has passed (9:59 AM has rolled over to
10:00 AM). Likewise, daily data is computed once the day has passed into the next (11:59 PM
has rolled over to 12:00 AM). Changing the time frame displays time-slice data points, each of
which represent a certain time range, such as a single minute of data or a full hour of data.
The granularity of the time-slice data points is determined initially by the length of the
selected time interval, but you can then use the "Select Granularity of Data Points" option to
display different time-slice data points for the same time frame.
The granularity of time-slice data points is determined initially by the length of time frame
(the duration from the start time to the end time), according to the following thresholds:
Less than or equal to 60 minutes: 1 Minute data points
Less than or equal to 12 Hours: 10 Minute data points
Less than or equal to 3 Days: Hourly data points
Less than or equal to 30 Days: Daily data points
More than 30 Days: Weekly data points
Select Granularity of Data Points —Lets you change the granularity of the time-slice data points
that are shown in the graph. The options for granularity are 1 Minute, 10 Minute, Hourly,
Daily, and Weekly. The way this works is that the less granular data (representing longer time
intervals) are aggregates of the more granular data. For example, a 10 minute data point
representing 6:20 would be an aggregate of all 1 minute data from 6:20 to 6:29. Likewise, an
hourly data point from 6:00 would be an aggregate of all 1 minute data from 6:00 to 6:59.
When you select a time frame, the length of the interval determines the granularity of the
data points that are shown at first, but you can change this. For example, the time frame Last
24 Hours will by default show hourly data points, but you can then see more granular data by
selecting 10 Minute from this menu. It would even be possible to show 1 Minute data for this
same time frame, but this might cause the web browser to perform poorly because there
would be hundreds of data points.
Search —Displays a search dialogue to find specific traffic data.
Select Report Type —Lets you change the number of results that are shown and also whether to
show the most or least significant results. You can choose between Top 5, 10 or 25 and Bottom
5, 10 or 25.
Select Mode of Calculation — Lets you change the mode of calculation for data values. NetFlow
and sFlow data are often sampled, which means that the values reported by the exporters
should be understood as representing only a fraction of the total traffic. You can choose to
show either the reported sampled values or the estimated total values. The estimates are
calculated by multiplying the sampled values by the sampling rate, as reported by the exporter
in one of the following ways:
- sFlow sampling, where the sampling rate is in the packet (usually 512 or 1024 or some
power of 2)
- NetFlow V5, where the sampling rate is in the header of the packet