HP FlexNetwork NJ5000, User Manual

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Configuring RMON
Overview
Remote Network Monitoring (RMON) is an enhancement to SNMP. It enables proactive remote
monitoring and management of network devices and subnets. An RMON monitor periodically or
continuously collects traffic statistics for the network attached to a port on the managed device. The
managed device can automatically send a notification when a statistic crosses an alarm threshold,
so the NMS does not need to constantly poll MIB variables and compare the results.
RMON uses SNMP notifications to notify NMSs of various alarm conditions such as broadcast traffic
threshold exceeded. In contrast, SNMP reports function and interface operating status changes such
as link up, link down, and module failure.
HPE devices provide an embedded RMON agent as the RMON monitor. An NMS can perform basic
SNMP operations to access the RMON MIB.
Working mechanism
RMON monitors typically take one of the following forms:
•
Dedicated RMON probes
—NMSs can obtain management information from RMON probes
directly and control network resources. NMSs can obtain all RMON MIB information by using
this method.
•
RMON agents embedded in network devices
—NMSs exchange data with RMON agents by
using basic SNMP operations to gather network management information. Because this
method is resource intensive, most RMON agent implementations provide only four groups of
MIB information: alarm, event, history, and statistics.
You can configure your device to collect and report traffic statistics, error statistics, and performance
statistics.
RMON groups
Among the RFC 2819 defined RMON groups, HPE devices implement the statistics group, history
group, event group, and alarm group supported by the public MIB. HPE devices also implement a
private alarm group, which enhances the standard alarm group.
Ethernet statistics group
The statistics group defines that the system collects various traffic statistics on an interface (only
Ethernet interfaces are supported), and saves the statistics in the Ethernet statistics table
(ethernetStatsTable) for future retrieval. The interface traffic statistics include network collisions,
CRC alignment errors, undersize/oversize packets, broadcasts, multicasts, bytes received, and
packets received.
After you create a statistics entry for an interface, the statistics group starts to collect traffic statistics
on the interface. The statistics in the Ethernet statistics table are cumulative sums.
History group
The history group defines that the system periodically collects traffic statistics on interfaces and
saves the statistics in the history record table (ethernetHistoryTable). The statistics include
bandwidth utilization, number of error packets, and total number of packets.
The history statistics table record traffic statistics collected for each sampling interval. The sampling
interval is user-configurable.