Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) - Manual (Page 1986)

RMON Introduction and Configuration
Software Reference for x310 Series Switches
73.2 AlliedWare Plus TM Operating System - Version 5.4.4C C613-50046-01 REV A
Introduction
The chapter describes the Remote Network MONitoring (RMON) service on the switch,
and describes a configuration example showing how to set up an RMON alarm.
This RMON alarm configuration example described creates SNMP traps and log messages
when the rate of receipt of Broadcast packets on a switch port exceeds a threshold, and
creates SNMP traps and log messages when the rate of receipt of Broadcast packets on a
switch drops below a lower threshold.
For detailed information about the commands used to configure RMON, see Chapter 74,
RMON Commands
RMON is disabled by default in AlliedWare Plus
TM
. No RMON alarms or events are
configured.
Overview
The Remote Network MONitoring (RMON) MIB (RFC2819) was developed by the IETF to
support monitoring and protocol analysis of LANs with a focus on Layer 1 and 2
information in networks. RMON is an industry standard that provides the functionality in
network analyzers.
An RMON implementation operates in a client/server model. Monitoring devices (or
‘probes’) contain RMON agents that collect information and analyze packets. The probes
are servers and the Network Management applications that communicate with them are
clients. While agent configuration and data collection uses SNMP, RMON operates
differently than SNMP systems:
■ Probes have responsibility for data collection and processing, reducing SNMP traffic
and reducing processing load for clients.
■ Information is only transmitted to the management application when required, not
polled.
RMON is mainly used for ‘flow-based’ monitoring, while SNMP is mainly used for ‘device-
based’ management. RMON data collected deals mainly with traffic patterns on the
network, and SNMP data collected usually deals with the status of individual devices on
the network.
One disadvantage of flow based monitoring is that remote devices have much more of the
management burden, and require more resources. AlliedWare Plus minimizes the
management and resources burden by implementing a subset of the RMON MIB group to
provide a minimal RMON agent implementation supporting statistics, history, alarms, and
events.
The RMON groups supported in AlliedWare Plus
TM
are:
■ Statistics - collects ethernet statistics on a switch port, such as utilization and
collisions.
■ History - collects a history of ethernet statistics on a switch port.
■ Alarms - monitor a MIB object for a specified interval, trigger an alarm at a specified
value (the ‘rising threshold’), and resets the alarm at another value (the ‘falling
threshold’). Alarms are used with events to trigger alarms, which generate logs or
SNMP traps.
■ Events - specify the action to take when an event is triggered by an alarm.
The action of an event can generate a log or an SNMP trap.