Brocade Fabric Watch Administrator's Guide (53-1000243-01, November 2006)

Fabric Watch Administrator’s Guide 1-15
Publication Number: 53-1000243-01
Configuring Events
1
Time Bases
Time bases are time periods within Fabric Watch. This configurable field impacts the comparison of
sensor-based data with user-defined threshold values.
Setting Time Base to None
If you set a time base to none, Fabric Watch compares a data value against a threshold boundary level.
When the absolute value of the measuring counter exceeds the threshold boundary, an event is triggered.
Figure 1-3 shows a high limit of 65 degrees Celsius placed on a counter measuring temperature. During
each sample period, Fabric Watch measures the temperature and compares it against the high threshold.
If the measured temperature exceeds the high threshold, it triggers an event.
Figure 1-3 Time Base Set to None
Specifying a Time Base
If you specify a time base value other than none (seconds, minute, hour, or day), Fabric Watch does not
use the current data value. Instead, it calculates the difference between the current data value and the data
value as it existed one time base ago. It compares this difference to the threshold boundary limit.
For example, if you specify the time base minute, Fabric Watch calculates the counter value difference
between two samples a minute apart. It then compares the difference (current data value – data value one
minute ago) against the preset threshold boundary.
When you set a time base to a value other than none, there are two main points to remember when
configuring events:
• Fabric Watch triggers an event only if the difference in the data value exceeds the preset
threshold boundary limit.
• Even if the current data value exceeds the threshold, Fabric Watch does not trigger an event if
the rate of change is below the threshold limit.