Operation Manual – SNMP-RMONH3C S3100 Series Ethernet Switches Chapter 2 RMON Configuration2-2RMON probe function. Through the RMON-capable SNMP agents running on theEthernet switch, an NMS can obtain the information about the total traffic, errorstatistics and performance statistics of the network segments to which the ports of themanaged network devices are connected. Thus, the NMS can further manage thenetworks.2.1.2 Commonly Used RMON GroupsI. Event groupEvent group is used to define the indexes of events and the processing methods of theevents. The events defined in an event group are mainly used by entries in the alarmgroup and extended alarm group to trigger alarms.You can specify a network device to act in one of the following ways in response to anevent:z Logging the eventz Sending trap messages to the NMSz Logging the event and sending trap messages to the NMSz No processingII. Alarm groupRMON alarm management enables monitoring on specific alarm variables (such as thestatistics of a port). When the value of a monitored variable exceeds the threshold, analarm event is generated, which then triggers the network device to act in the waydefined in the events. Events are defined in event groups.With an alarm entry defined in an alarm group, a network device performs the followingoperations accordingly:z Sampling the defined alarm variables periodicallyz Comparing the samples with the threshold and triggering the correspondingevents if the former exceed the latterIII. Extended alarm groupWith extended alarm entry, you can perform operations on the samples of alarmvariables and then compare the operation results with the thresholds, thus implementmore flexible alarm functions.With an extended alarm entry defined in an extended alarm group, the network devicesperform the following operations accordingly:z Sampling the alarm variables referenced in the defined extended alarmexpressions periodicallyz Performing operations on the samples according to the defined expressionsz Comparing the operation results with the thresholds and triggering correspondingevents if the operation result exceeds the thresholds.
