PRTG Manual: SNMP RMON Sensor

The SNMP RMON sensor monitors traffic on a device using the Remote Monitoring (RMON) standard via the Simple Network Management Protocol (SNMP).

You can create it on an SNMP-compatible device that provides traffic data via RMON. Depending on the data that the device returns, PRTG displays traffic data for each port in different channels, which allows a detailed analysis. If available, the sensor queries 64-bit counters.

SNMP RMON Sensor

For a detailed list and descriptions of the channels that this sensor can show, see section Channel List.

Sensor in Other Languages

Dutch: SNMP RMON
French: RMON (SNMP)
German: SNMP RMON
Japanese: SNMP RMON
Portuguese: RMON (SNMP)
Russian: RMON по SNMP
Simplified Chinese: SNMP RMON
Spanish: RMON (SNMP)

Remarks

Consider the following remarks and requirements for this sensor:

Remark	Description
Localhost	It might not work to query data from a probe device via SNMP (querying localhost, 127.0.0.1, or ::1). Add this device with the IP address that it has in your network and create the sensor on this device instead.
IPv6	This sensor supports IPv6.
Performance impact	This sensor has a very low performance impact.
Port name templates	You can define the displayed sensor name with port name templates in the SNMP compatibility options of the parent device.
Knowledge Base	Knowledge Base: What value does the Transmitted channel of an RMON sensor show? Knowledge Base: Automatically update port name and number for SNMP Traffic sensors when the device changes them Knowledge Base: Where is the volume line in graphs?

Basic Sensor Settings

The sensor has the following default tags that are automatically predefined in the sensor's settings when you add the sensor:

snmprmon

For more information about basic sensor settings, see section Sensor Settings.

RMON Specific

Setting	Description
Port	The number of the interface port that this sensor monitors.
Channel Mask	Describes which channels are available. This information might be useful for the Paessler support team.

Sensor Display

Setting	Description
Primary Channel	Select a channel from the list to define it as the primary channel. In the device tree, PRTG displays the last value of the primary channel below the sensor's name. The available options depend on what channels are available for this sensor. You can set a different primary channel later by clicking below a channel gauge on the sensor's Overview tab.
Graph Type	Define how this sensor shows different channels: Show channels independently (default): Show a graph for each channel. Stack channels on top of each other: Stack channels on top of each other to create a multi-channel graph. This generates a graph that visualizes the different components of your total traffic. You cannot use this option in combination with manual Vertical Axis Scaling (available in the channel settings).
Stack Unit	This setting is only visible if you select Stack channels on top of each other above. Select a unit from the list. PRTG stacks all channels with this unit on top of each other. By default, you cannot exclude single channels from stacking if they use the selected unit. However, there is an advanced procedure to do so.

Setting

Description

Primary Channel

Select a channel from the list to define it as the primary channel. In the device tree, PRTG displays the last value of the primary channel below the sensor's name. The available options depend on what channels are available for this sensor.

You can set a different primary channel later by clicking below a channel gauge on the sensor's Overview tab.

Graph Type

Define how this sensor shows different channels:

Show channels independently (default): Show a graph for each channel.
Stack channels on top of each other: Stack channels on top of each other to create a multi-channel graph. This generates a graph that visualizes the different components of your total traffic.
You cannot use this option in combination with manual Vertical Axis Scaling (available in the channel settings).

Stack Unit

This setting is only visible if you select Stack channels on top of each other above.

Select a unit from the list. PRTG stacks all channels with this unit on top of each other. By default, you cannot exclude single channels from stacking if they use the selected unit. However, there is an advanced procedure to do so.

Inherited Settings

By default, all of these settings are inherited from objects that are higher in the hierarchy. We recommend that you change them centrally in the root group settings if necessary. To change a setting for this object only, click under the corresponding setting name to disable the inheritance and to display its options.

For more information, see section Inheritance of Settings.

Channel List

Which channels the sensor actually shows might depend on the target device, the available components, and the sensor setup.

Channel	Description
Broadcast Packets	The number of broadcast packets
Collisions	The number of collisions
CRC Errors	The number of CRC errors
Downtime	In the channel table on the Overview tab, this channel never shows any values. PRTG uses this channel in graphs and reports to show the amount of time in which the sensor was in the Down status
Drop Events	The number of drop events
Fragments	The number of fragments
Jabbers	The number of jabbers
Multicast Packets	The number of multicast packets
Oversize Packets	The number of oversize packets
Packets	The number of packets
Packets <= 64 Byte	The number of packets with less than or equal to 64 bytes
Packets 65 - 127 Bytes	The number of packets with 65 - 127 bytes
Packets 128 - 255 Bytes	The number of packets with 128 - 255 bytes
Packets 256 - 511 Bytes	The number of packets with 256 - 511 bytes
Packets 512 - 1023 Bytes	The number of packets with 512 - 1023 bytes
Packets 1024 - 1518 Bytes	The number of packets with 1024 - 1518 bytes
Transmitted	The transmitted bytes This channel is the primary channel by default.
Undersize Packets	The number of undersize packets