3com WX3000 User Manual

 

2-2 

Event group is used to define the indexes of events and the processing methods of the events. The 

events defined in an event group are mainly used by entries in the alarm group and extended alarm 

group to trigger alarms. 

You can specify a network device to act in one of the following ways in response to an event: 

z 

Logging the event 

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Sending trap messages to the NMS 

z 

Logging the event and sending trap messages to the NMS 

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No processing 

RMON alarm management enables monitoring on specific alarm variables (such as the statistics of a 

port). When the value of a monitored variable exceeds the threshold, an alarm event is generated, 

which then triggers the network device to act in the way defined in the events. Events are defined in 

event groups. 

With an alarm entry defined in an alarm group, a network device performs the following operations 

accordingly: 

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Sampling the defined alarm variables periodically 

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Comparing the samples with the threshold and triggering the corresponding events if the former 

exceed the latter 

With extended alarm entry, you can perform operations on the samples of alarm variables and then 

compare the operation results with the thresholds, thus implement more flexible alarm functions. 

With an extended alarm entry defined in an extended alarm group, the network devices perform the 

following operations accordingly: 

z 

Sampling the alarm variables referenced in the defined extended alarm expressions periodically 

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Performing operations on the samples according to the defined expressions 

z 

Comparing the operation results with the thresholds and triggering corresponding events if the 

operation result exceeds the thresholds. 

After a history group is configured, the device collects network statistics information periodically and 

stores the statistics information temporarily for later use. A history group can provide the history data of 

the statistics on network segment traffic, error packets, broadcast packets, and bandwidth utilization. 

With the history data management function, you can configure network devices to collect history data, 

sample and store data of a specific port periodically. 

Statistics group contains the statistics of each monitored port on the device. An entry in a statistics 

group is an accumulated value counting from the time when the statistics group is created.