Device and Sensor Setup > Sensor Settings

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

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.

This sensor supports IPv6.

This sensor has a very low performance impact.

You can define the displayed sensor name with port name templates in the SNMP compatibility options of the parent device.

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

Setting	Description
Sensor Name	Enter a name to identify the sensor. By default, PRTG shows this name in the device tree, as well as in alarms, logs, notifications, reports, maps, libraries, and tickets. If the name contains angle brackets (<>), PRTG replaces them with braces ({}) for security reasons. For more information, see the Knowledge Base: What security features does PRTG include?
Parent Tags	The tags that the sensor inherits from its parent device, parent group, and parent probe. This setting is for your information only. You cannot change it.
Tags	Enter one or more tags. Confirm each tag with the Spacebar key, a comma, or the Enter key. You can use tags to group objects and use tag-filtered views later on. Tags are not case-sensitive. Tags are automatically inherited. It is not possible to enter tags with a leading plus (+) or minus (-) sign, nor tags with parentheses (()) or angle brackets (<>). For performance reasons, it can take some minutes until you can filter for new tags that you added. The sensor has the following default tags that are automatically predefined in the sensor's settings when you add the sensor: snmprmon
Priority	Select a priority for the sensor. This setting determines the position of the sensor in lists. The highest priority is at the top of a list. Choose from the lowest priority () to the highest priority ().

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, the last value of the primary channel is always displayed 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 different channels are shown for this sensor: 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. All channels with this unit are stacked 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, the last value of the primary channel is always displayed 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 different channels are shown for this sensor:

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. All channels with this unit are stacked 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.

Scanning Interval

For more information, see section Root Group Settings, section Scanning Interval.

Schedules, Dependencies, and Maintenance Window

You cannot interrupt the inheritance for schedules, dependencies, and maintenance windows. The corresponding settings from the parent objects are always active. However, you can define additional schedules, dependencies, and maintenance windows. They are active at the same time as the parent objects' settings.

Schedules, Dependencies, and Maintenance Window

For more information, see section Root Group Settings, section Schedules, Dependencies, and Maintenance Window.

Access Rights

For more information, see section Root Group Settings, section Access Rights.

Channel Unit Configuration

Which channel units are available depends on the sensor type and the available parameters. If no configurable channels are available, this field shows No configurable channels.

Channel Unit Configuration

For more information, see section Root Group Settings, section Channel Unit Configuration.

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