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CLI-based Configuration Guide - Network Management and Monitoring

AR100, AR120, AR150, AR160, AR200, AR1200, AR2200, AR3200, and AR3600 V200R009

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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Overview of RMON and RMON2

Overview of RMON and RMON2


Remote Network Monitoring (RMON) and RMON2 implementation is based on SNMP and uses the same network management station (NMS) as SNMP to manage network elements. RMON, defined by IETF, is a widely used network management protocol. It provides packet statistics and alarm functions for Ethernet interfaces. The management devices use RMON to remotely monitor and manage network elements. RMON2 is an enhancement of RMON. Currently, the device can collect and analyze statistics on IP packets.

SNMP collects statistics about network communication by using the agent software embedded in the managed devices. The NMS polls the agent to provide network communication information. The agent then searches the Management Information Base (MIB) and returns the required information to the NMS. The NMS can manage the network based on returned information. The MIB counter only records the statistics, but cannot analyze history information about routine communication. To display traffic volume and changes on a whole day, the NMS has to keep on polling and analyze network traffic based on the obtained information.

SNMP polling has the following disadvantages:

  • Occupies a large number of network resources. Polling generates many communication packets. On a large-sized network, congestion may occur or even the network is blocked. Therefore, SNMP is not applicable to large-sized networks and cannot recycle large amount of data, such as routing information.
  • Increases the burden of network administrators. The network administrators are responsible for collecting all data using the NMS software. It is difficult for an administrator to monitor more than three network segments.

IETF develops RMON to improve usability of network management information and lighten the burden on the NMS and network administrators. Compared with SNMP, RMON is more applicable to large-sized networks and can monitor traffic on one or multiple network segments. The characteristics of RMON are as follows:

  • SNMP is the basis of RMON, and RMON is an enhancement of SNMP.

    RMON is implemented based on the SNMP structure and compatible with SNMP. It consists of NMS and agents. Network administrators can use the SNMP NMS to implement RMON without additional training.

  • RMON enables SNMP to monitor remote network devices effectively and actively.

    Using RMON, managed devices automatically send traps when alarm thresholds are exceeded. Therefore, the management devices do not need to obtain MIB variables by continuous polling and comparison. The RMON reduces traffic volume between the management and managed devices, and allows large-size networks to be more easily and effectively managed.

RMON defines multiple monitors to collect network management information in either of the following ways:

  • The NMS obtains management information directly from the RMON probe and controls network resources. This allows the NMS to obtain all RMON MIB information.
  • A RMON agent is embedded into a network device, so that the device can provide the RMON probe function. The NMS uses SNMP protocol to exchange data with the RMON agent and collect network management information. Due to the limitation on resources, the NMS can only obtain information about statistics, history, alarms, and events groups.

Huawei devices have embedded RMON agent. The management device can obtain information including traffic volume, error packet statistics, and performance statistics of the entire network segment connected to the interfaces on the managed devices to implement network monitoring.


RMON2 is an extension of RMON, and has the same mechanism as RMON.

RMON and RMON2 both monitor traffic on Ethernet links; however, RMON monitors traffic at only MAC layer and RMON2 monitors traffic at the upper layers above MAC layer.

RMON2 codes and decodes data packets from Layer 3 to Layer 7 of the OSI model. In RMON2, the RMON agents provide two major functions:

  • Monitor traffic based on network layer protocols and addresses, including IP protocol. This enables the agent to learn its connected external LAN network segment and monitor traffic flowing to the LAN through the switch.
  • Record the incoming and outgoing traffic of the specific application, such as email, FTP, and WWW because it can decode and monitor the traffic.

The RMON agent on Huawei devices can collect statistics about IP packets on the network segments connected to the managed devices, and monitors traffic flowing to these interfaces from the hosts on the network segments.

Updated: 2019-05-17

Document ID: EDOC1000174072

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