Brocade Fabric Watch Administrator's Guide - Supporting Fabric OS v5.3.0 (53-1000438-01, June 2007)

18 Fabric Watch Administrator’s Guide
53-0000438-01
Port persistence
1
In-between event triggers
Fabric Watch event triggers are usually set to notify the user of a warning or failure condition, but
there is an exception. You can define the In-Between event trigger to receive a notification of fault
recovery. For example, when measuring port performance, crossing the high threshold triggers an
Above threshold event, which displays a warning message. The threshold might be crossed for a
period so brief that is not a true cause for an alarm. An In-Between event trigger indicates that the
port performance has returned to the acceptable range.
Use the In-Between event trigger to:
- Verify a successful recovery from a faulty condition.
- Reset the counter value for the next event.
- Identify an element that is consistently operating under marginal condition.
Figure 8 illustrates event notification using an In-Between event trigger. The arrow marked with one
indicates the point at which event notification occurs.
FIGURE 8 In-between event trigger
Fabric Watch alarm behavior
Fabric Watch alarm behavior depends on the threshold states associated with the Above, Below
and Changed thresholds. Threshold states can be INFORMATIVE, IN_RANGE, and OUT_OF_RANGE.
Alarms are generated only for the following transitions:
• IN_RANGE to OUT_OF_RANGE
An alarm is generated
• OUT_OF_RANGE to IN_RANGE
An alarm is generated
No alarm is generated for INFORMATIVE to IN_RANGE (or IN_RANGE to INFORMATIVE)
See Appendix , “Default Threshold Values” for more details about the threshold states for Above,
Below, and Changed.
Port persistence
The data collected in port monitoring can vary a great deal over short time periods. Therefore, the
port can become a source of frequent event messages (the data can exceed the threshold range
and return to a value within the threshold range).