H3C Technologies H3C S3600 Series Switches - Manual (Page 863)

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about the total traffic, error statistics and performance statistics of the network segments to which the
ports of the managed network devices are connected. Thus, the NMS can further manage the networks.
Commonly Used RMON Groups
Event group
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
z Sending traps to the NMS
z Logging the event and sending traps to the NMS
z No processing
Alarm group
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:
z Sampling the defined alarm variables periodically
z Comparing the samples with the threshold and triggering the corresponding events if the former
exceed the latter
Extended alarm group
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
z 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.
History group
After a history group is configured, the Ethernet switch 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.