Configuring Rmon; Overview; Working Mechanism; Rmon Groups - HP 1920 Gigabit Ethernet Switch Series User Manual

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.
HP 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, HP implements the statistics group, history group, event
group, and alarm group supported by the public MIB. HP also implements 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.
93