2-2An H3C S5600 Ethernet switch implements RMON in the second way. With an RMON agentembedded in, an S5600 Ethernet switch can serve as a network device with the RMONprobe function. Through the RMON-capable SNMP agents running on the Ethernet switch,an NMS can obtain the information about the total traffic, error statistics and performancestatistics of the network segments to which the ports of the managed network devices areconnected. Thus, the NMS can further manage the networks.Commonly Used RMON GroupsEvent 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 alarm groupand 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 traps to the NMSz Logging the event and sending traps to the NMSz No processingAlarm 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 way definedin 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 corresponding events ifthe former exceed the latterExtended alarm groupWith extended alarm entry, you can perform operations on the samples of alarm variablesand then compare the operation results with the thresholds, thus implement more flexiblealarm 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 alarm expressionsperiodicallyz 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.History groupAfter a history group is configured, the Ethernet switch collects network statisticsinformation periodically and stores the statistics information temporarily for later use. A
