122 APPENDIX C: RMONAbout the RMON GroupsThe IETF define nine groups of Ethernet RMON statistics. This sectiondescribes these groups, and details how they can be used.StatisticsThe Statistics group provides traffic and error statistics showingpackets, bytes, broadcasts, multicasts and errors on a LAN segment.Information from the Statistics group is used to detect changes intraffic and error patterns in critical areas of your network.HistoryThe History group provides historical views of network performanceby taking periodic samples of the counters supplied by the Statisticsgroup. The group features user-defined sample intervals and bucketcounters for complete customization of trend analysis.The group is useful for analysis of traffic patterns and trends on aLAN segment, and to establish baseline information indicatingnormal operating parameters.AlarmsThe Alarms group provides a versatile, general mechanism for settingthresholds and sampling intervals to generate events on any counteror integer variable. Both rising and falling thresholds are supported,and thresholds can be on the absolute value of a variable or its deltavalue. In addition, the 3Com SmartAgent allows alarm thresholds tobe autocalibrated.Alarms are used to inform you of a network performance problemand they can trigger automated action responses through the Eventsgroup.HostsThe Hosts group specifies a table of traffic and error statistics foreach host on a LAN segment. Statistics include packets sent andreceived, octets sent and received, as well as broadcasts, multicasts,and error packets sent.The group supplies a simple discovery mechanism listing all hosts thathave transmitted. The next group, Hosts Top N, requiresimplementation of the Hosts group.
