Extreme Networks ExtremeWare 7.2e, Installation And User Manual

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RMON
ExtremeWare 7.2e Installation and User Guide 139
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 user-defined sample intervals and bucket
counters for complete customization of trend analysis.
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 can
be autocalibrated or set manually.
Alarms inform you of a network performance problem and can trigger automated action responses
through the Events group.
Events
The Events group creates entries in an event log and/or sends SNMP traps to the management
workstation. An event is triggered by an RMON alarm. The action taken can be configured to ignore it,
to log the event, to send an SNMP trap to the receivers listed in the trap receiver table, or to both log
and send a trap. The RMON traps are defined in RFC 1757 for rising and falling thresholds.
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, which provides a mechanism for an automated response to certain
occurrences.
Configuring RMON
RMON requires one probe per LAN segment, and standalone RMON probes traditionally have been
expensive. Therefore, Extreme’s approach has been to build an inexpensive RMON probe into the agent
of each system. This allows RMON to be widely deployed around the network without costing more
than traditional network management. The switch accurately maintains RMON statistics at the
maximum line rate of all of its ports.
For example, statistics can be related to individual ports. Also, because a probe must be able to see all
traffic, a stand-alone probe must be attached to a nonsecure port. Implementing RMON in the switch
means that all ports can have security features enabled.
To enable or disable the collection of RMON statistics on the switch, use one of the following
commands:
enable rmon
disable rmon
By default, RMON is disabled. However, even in the disabled state, the switch responds to RMON
queries and sets for alarms and events. By enabling RMON, the switch begins the processes necessary
for collecting switch statistics.