Creating Alarms; Figure 8 Alarm Example-Threshold Less Than 260 - Nortel Passport 8600 Configuring

44 Chapter 2 Configuring RMON
The first time outbound traffic other than spanning tree Bridge Protocol Data
Units (BPDUs) occurs, the rising alarm fires. When outbound traffic other than
spanning tree ceases, the falling alarm fires. This process provides the system
administrator with time intervals of any nonbaseline outbound traffic.
If the alarm is defined with a falling threshold less than 260 (assuming the alarm
polling interval is 10 seconds), say 250, then the rising alarm can fire only once
(Figure
alarm (the opposite threshold) must fire. Unless the port goes inactive or spanning
tree is disabled (which would cause the value for outbound octets to drop to zero),
the falling alarm cannot fire because the baseline traffic is always greater than the
value of the falling threshold. By definition, the failure of the falling alarm to fire
prevents the rising alarm from firing a second time.
Figure 8 Alarm example—threshold less than 260
Rising threshold = 320
Baseline traffic = 260
Falling threshold = 250
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Creating alarms

When you create an alarm, you select a variable from the variable list
(Appendix A, "RMON alarm variables," on page
component, to which it is connected. Some variables require port IDs, card IDs, or
other indexes (for example, spanning tree group IDs). You then select a rising and
a falling threshold value. The rising and falling values are compared against the
actual value of the variable that you choose. If the variable falls outside of the
rising or falling value range, an alarm is triggered and an event is logged or
trapped.
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8). The reason is that for the rising alarm to fire a second time, the falling
Creating a port history alarm
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206) and a port, or other switch