120CHAPTER 8: STATUS MONITORING AND STATISTICS
About the RMON The IETF defines nine groups of Ethernet RMON statistics. The switch Groups supports the following four of these groups:
■Statistics
■History
■Alarms
■Events
This section describes these groups, and discusses how they can be used.
Statistics
The RMON Ethernet 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 the 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 features
The group is useful for analysis of traffic patterns and trends on a LAN segment or VLAN, and to establish baseline information indicating normal operating parameters.
Alarms
The Alarms group provides a versatile, general mechanism for setting threshold and sampling intervals to generate events on any RMON variable. Both rising and falling thresholds are supported, and thresholds can be on the absolute value of a variable or its delta value. In addition, alarm thresholds may be autocalibrated or set manually.
Alarms inform you of a network performance problem and can trigger automated action responses through the Events group.
