Operation Manual – SNMP-RMONH3C S3100-52P Ethernet switch Chapter 2 RMON Configuration2-3III. 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.IV. History groupAfter a history group is configured, the Ethernet switch collects network statisticsinformation periodically and stores the statistics information temporarily for later use. Ahistory 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 tocollect history data, sample and store data of a specific port periodically.V. Statistics groupStatistics group contains the statistics of each monitored port on a switch. An entry in astatistics group is an accumulated value counting from the time when the statisticsgroup is created.The statistics include the number of the following items: collisions, packets with CyclicRedundancy Check (CRC) errors, undersize (or oversize) packets, broadcast packets,multicast packets, and received bytes and packets.With the RMON statistics management function, you can monitor the use of a port andmake statistics on the errors occurred when the ports are being used.2.2 RMON ConfigurationBefore performing RMON configuration, make sure the SNMP agents are correctlyconfigured. For the information about SNMP agent configuration, refer to sectionConfiguring Basic SNMP Functions.
