56 CHAPTER 7: STATUS MONITORING AND STATISTICS
Statistics
The Statistics group provides traffic and error statistics showing packets, 
bytes, broadcasts, multicasts and errors on a LAN segment or VLAN. 
Information from the Statistics group is used to detect changes in traffic 
and error patterns in critical areas of your network.
History
The History group provides historical views of network performance by 
taking periodic samples of the counters supplied by the Statistics group.
The group is useful for analyzing the traffic patterns and trends on a LAN 
segment or VLAN, and for establishing the normal operating parameters 
of your network.
Alarms
The Alarms group provides a mechanism for setting thresholds and 
sampling intervals to generate events on any RMON variable. 
Alarms are used to inform you of network performance problems and 
they can trigger automated responses through the Events group.
Events
The Events group provides you with the ability to create entries in an 
event log and send SNMP traps to the management workstation. Events 
are the action that can result from an RMON alarm. In addition to the 
standard five traps required by SNMP (link up, link down, warm start, cold 
start, and authentication failure), RMON adds two more: rising threshold 
and falling threshold.
Effective use of the Events group saves you time; rather than having to 
watch real-time graphs for important occurrences, you can depend on 
the Event group for notification. Through the SNMP traps, events can 
trigger other actions, therefore providing a way to automatically respond 
to certain occurrences.