Operation Manual – SNMP and RMONH3C S7500 Series Ethernet Switches Chapter 2 RMON Configuration2-2an NMS operating in this way can only obtain information about four groups(instead of all the information in the RMON MIB). The four groups are alarm group,event group, history group and statistics group.An S7500 switch implements RMON in the second way. With the embedded RMONagent, the S7500 series switch can serve as a network device with the RMON probefunction. Through the RMON-capable SNMP agents running on the Ethernet switch, anNMS can obtain the information on the total traffic, error statistics and performancestatistics of the network segments to which the ports of the managed network devicesare connected. Thus, the NMS can further manage the networks.2.1.2 Commonly Used RMON GroupsI. Event groupThe event group is used to define event indexes and the processing methods for theevents. The events defined in an event group are mainly used in alarm group andextended 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 monitors on specific alarm variables (such as thestatistics of a port). When the value of a monitored variable exceeds the upperthreshold or lower threshold, an alarm event is generated, which triggers the networkdevice to act in the set way. 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 (alarm-variable) once in each specifiedperiod (sampling-time)z Comparing the sampled value with the set threshold and triggering thecorresponding events if the sampled value exceeds the thresholdIII. Extended alarm groupWith extended alarm entries, you can perform operations on the samples of an alarmvariable and then compare the operation result with the set threshold, thusimplementing more flexible alarm functions.With an extended alarm entry defined in an extended alarm group, the network devicesperform the following operations accordingly:
