Creating Alarms; Figure 66 Alarm Example - Threshold Less Than 260 - Nortel BayStack 380-24F Reference

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 66 Alarm example — threshold less than 260
Rising threshold = 326?
Baseline traffic = 260
Falling threshold = 250

Creating alarms

When you create an alarm, you select a variable from the variable list and a port,
or other switch component, to which it is connected. Some variables require port
IDs, card IDs, or other indices (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.
When you create an alarm, you also select a sample type, which can be either
absolute or delta. Absolute alarms are defined on the cumulative value of the
alarm variable. An example of an alarm defined with absolute value is card
operating status. Because this value is not cumulative, but instead represents
states, such as card up (value 1) and card down (value 2), you set it for absolute
value. Therefore, an alarm could be created with a rising value of 2 and a falling
value of 1 to alert a user to whether the card is up or down.
Most alarm variables related to Ethernet traffic are set to delta value. Delta alarms
are defined based on the difference in the value of the alarm variable between the
start of the polling period and the end of the polling period. Delta alarms are
sampled twice per polling period. For each sample, the last two values are added
together and compared to the threshold values. This process increases precision
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