3com S7906E 설치 설명서

 

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RMON allows multiple monitors (management devices). A monitor provides two ways of data gathering: 

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Using RMON probes. Management devices can obtain management information from RMON 

probes directly and control network resources. In this approach, management devices can obtain 

all RMON MIB information. 

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Embedding RMON agents in network devices such as routers, switches, and hubs to provide the 

RMON probe function. Management devices exchange data with RMON agents using basic SNMP 

operations to gather network management information, which, due to system resources limitation, 

may not cover all MIB information but four groups of information, alarm, event, history, and 

statistics, in most cases. 

The 3Com device adopts the second way and realizes the RMON agent function. 

With the RMON agent 

function, the management device can monitor all the traffic flowing among the managed devices on all 

connected LAN segments; obtain information about error statistics and performance statistics for network 

management.

 

Among the RMON groups defined by RMON specifications (RFC 2819), the realized public MIB of the 

device supports the event group, alarm group, history group and statistics group. Besides, 3Com also 

defines and implements the private alarm group, which enhances the functions of the alarm group. This 

section describes the five kinds of groups in general. 

The statistics group defines that the system collects statistics on various traffic information on an 

interface (at present, only Ethernet interfaces are supported) and saves the statistics in the Ethernet 

statistics table (ethernetStatsTable) for query convenience of the management device. It provides 

statistics about network collisions, CRC alignment errors, undersize/oversize packets, broadcasts, 

multicasts, bytes received, packets received, and so on. 

After the creation of a statistics entry on an interface, the statistics group starts to collect traffic statistics 

on the interface. The result of the statistics is a cumulative sum. 

The history group defines that the system periodically collects statistics on traffic information at an 

interface and saves the statistics in the history record table (ethernetHistoryTable) for query 

convenience of the management device. The statistics data includes bandwidth utilization, number of 

error packets, and total number of packets. 

A history group collects statistics on packets received on the interface during each period, which can be 

configured through the command line interface (CLI). 

The event group defines event indexes and controls the generation and notifications of the events 

triggered by the alarms defined in the alarm group and the private alarm group. The events can be 

handled in one of the following ways: 

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Log: Logging event related information (the occurred events, contents of the event, and so on) in 

the event log table of the RMON MIB of the device, and thus the management device can check the 

logs through the SNMP Get operation.