3com 3.01.01 User Manual

C

HAPTER

 11: S

YSTEM

 M

ANAGEMENT

NMS and the agent running on the network devices. On the network monitor or 
detector, RMON agent tracks and accounts for different traffic information on the 
segment connected to its port. For example, the total number of packets on a 
segment in a certain period of time or that of the correct packets sent to a host. 

RMON helps the SNMP monitor the remote network device more actively and 
effectively, which provides a highly efficient means for monitoring subnet 
operations. RMON can reduce communication traffic between the NMS and the 
agent, thus facilitating an effective management over large interconnected 
networks.

RMON allows multiple monitors. It can collect data in two ways.

1 The first way is with a special RMON probe. NMS directly obtains the management 

information from the RMON probe and controls the network resource. In this way, 
it obtains all the information of RMON MIB.

2 The second way is to implant the RMON Agent directly into the network devices, 

such as routers, switches, hubs, and so on, so that the devices become network 
facilities with RMON probe functions. RMON NMS uses the basic SNMP 
commands to exchange data information with the SNMP Agent and to collect NM 
information. However, not all the data of the RMON MIB can be obtained with this 
method, depending on resources. In most cases, only four groups of information 
can be collected. The four groups are: trap information, event information, history 
information and statistics information.

The Switch 8800 implements RMON using the second method. With the 
RMON-supported SNMP agent running on the network monitor, NMS can obtain 
such information as the overall traffic of the segment connected to the managed 
network device port, the error statistics and performance statistics, thereby 
implementing the management (usually remote) over the network. 

RMON configuration includes tasks described in the following sections:

■

■

■

■

■

■

RMON alarm management can monitor the specified alarm variables, such as, 
statistics on a port. When a value of the monitored data exceeds the defined 
threshold, an alarm event will be generated. Generally, the event will be recorded 
in the device log table and a Trap message will be sent to NMS. The events are 
defined in event management. The alarm management includes browsing, adding 
and deleting alarm entries. 

Use the following commands to add or delete an entry to or from the alarm table.