RMON Configuration 489
RMON Configuration Remote Network Monitoring (RMON) is a type of IETF-defined MIB. It is the most
important enhancement to the MIB II standard. It is mainly used for monitoring the
data traffic on a segment and even on a whole network. It is one of the most widely
used Network Management standards.
RMON is implemented fully based on the SNMP architecture (which is one of its
outstanding advantages) and compatible with the existing SNMP framework, and
therefore it is unnecessary to adjust the protocol. RMON includes NMS and the Agent
running on the network devices. On the network monitor or detector, RMON Agent
tracks and accounts different traffic information on the segment connected to its
port, such as 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 SNMP monitor the remote
network device more actively and effectively, which provides a highly efficient means
for the monitoring of the subnet operations. RMON can reduce the communication
traffic between the NMS and the agent, thus facilitating effective management over
large interconnected networks.
RMON allows multiple monitors. It can collect data in two ways.
■One is to collect data with a special RMON probe. NMS directly obtains the
management information from the RMON probe and controls the network
resource. In this way, it can obtain all the information of the RMON MIB.
■Another way is to implant the RMON Agent directly into the network devices (such
as a Switch, Hub), so that the devices become network facilities with RMON probe
function. RMON NMS uses the basic SNMP commands to exchange data
information with SNMP Agent and collect NM information. However, limited by
the device resources, normally, not all the data of the RMON MIB can be obtained
with this meth od. In most cas es, only four groups of information can be collected.
The four groups include trap information, event information, history information
and statistics information.
The Switch implements RMON as described in the second bullet point above. 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 (generally remote management) over the network.
Configuring RMON RMON configuration includes:
■Adding/Deleting an Entry to/from the Alarm Table
■Adding/Deleting an Entry to/from the Event Table
■Adding/Deleting an Entry to/from the History Control Terminal
■Adding/Deleting an Entry to/from the Extended RMON Alarm Table
■Adding/Deleting an Entry to/from the Extended RMON Alarm Table
Adding/Deleting an Entry to/from the Alarm Table
RMON alarm management can monitor the specified alarm variables such as the
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 the NMS. The events are
defined in the event management. The alarm management includes browsing,
adding and deleting the alarm entries.