RMON Configuration 489RMON Configuration Remote Network Monitoring (RMON) is a type of IETF-defined MIB. It is the mostimportant enhancement to the MIB II standard. It is mainly used for monitoring thedata traffic on a segment and even on a whole network. It is one of the most widelyused Network Management standards.RMON is implemented fully based on the SNMP architecture (which is one of itsoutstanding advantages) and compatible with the existing SNMP framework, andtherefore it is unnecessary to adjust the protocol. RMON includes NMS and the Agentrunning on the network devices. On the network monitor or detector, RMON Agenttracks and accounts different traffic information on the segment connected to itsport, such as the total number of packets on a segment in a certain period of time orthat of the correct packets sent to a host. RMON helps SNMP monitor the remotenetwork device more actively and effectively, which provides a highly efficient meansfor the monitoring of the subnet operations. RMON can reduce the communicationtraffic between the NMS and the agent, thus facilitating effective management overlarge 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 themanagement information from the RMON probe and controls the networkresource. 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 (suchas a Switch, Hub), so that the devices become network facilities with RMON probefunction. RMON NMS uses the basic SNMP commands to exchange datainformation with SNMP Agent and collect NM information. However, limited bythe device resources, normally, not all the data of the RMON MIB can be obtainedwith this method. In most cases, only four groups of information can be collected.The four groups include trap information, event information, history informationand statistics information.The Switch implements RMON as described in the second bullet point above. Withthe RMON-supported SNMP Agent running on the network monitor, NMS can obtainsuch information as the overall traffic of the segment connected to the managednetwork device port, the error statistics and performance statistics, therebyimplementing 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 TableAdding/Deleting an Entry to/from the Alarm TableRMON alarm management can monitor the specified alarm variables such as thestatistics on a port. When a value of the monitored data exceeds the definedthreshold, an alarm event will be generated. Generally, the event will be recorded inthe device log table and a trap message will be sent to the NMS. The events aredefined in the event management. The alarm management includes browsing,adding and deleting the alarm entries.
