Nortel Networks 214393-A manual Alarms, How RMON alarms work

Chapter 8 RMON 131

2Click the Ether Stats tab.

The Ether Stats tab opens (Figure 63 on page 130).

3Highlight the row that contains the port ID you want to delete.

4Click Delete.

The Ether Stats entry is removed from the table.

Alarms

Alarms are useful when you need to know when the values of a variable go out of range. You can define an RMON alarm for any MIB variable that resolves to an integer value. You cannot use string variables (such as system description) as alarm variables.

All alarms share the following characteristics:

•An upper and lower threshold value is defined.

•A corresponding rising and falling event occurs.

•An alarm interval or polling period is reached.

When alarms are activated, you can view the activity in a log or a trap log, or you can create a script to notify you by beeping a console, sending e-mail, or calling a pager.

How RMON alarms work

The alarm variable is polled and the result is compared against upper and lower limit values you select when you create the alarm. If either limit is reached or crossed during the polling period, then the alarm fires and generates an event that you can view in the event log or the trap log.

The alarm’s upper limit is called the rising value, and its lower limit is called the falling value. RMON periodically samples the data based upon the alarm interval. During the first interval that the data passes above the rising value, the alarm fires as a rising event. During the first interval that the data drops below the falling value, the alarm fires as a falling event (Figure 65).

Reference for the BayStack 380-24F Gigabit Switch Management Software