PRTG Manual: SNMP Traffic Sensor

The SNMP Traffic sensor monitors traffic on a device via the Simple Network Management Protocol (SNMP).

You can create the sensor on a device that provides traffic data.

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

Sensor in Other Languages

Dutch: SNMP Verkeer
French: Trafic (SNMP)
German: SNMP Datenverkehr
Japanese: SNMP トラフィック
Portuguese: Tráfego (SNMP)
Russian: Трафик по SNMP
Simplified Chinese: SNMP 流量
Spanish: Tráfico (SNMP)

Remarks

Consider the following remarks and requirements for this sensor:

Remark	Description
SNMP v2c or SNMP v3	We recommend that you select SNMP v2c (most common) or SNMP v3 in the credentials for SNMP devices of the parent device (if supported by the target device). SNMP v1 does not support 64-bit counters, which might result in invalid data. For more information, see the Knowledge Base: SNMP Traffic sensor suddenly drops at 610Mbps
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.
Auto-discovery	The auto-discovery always creates SNMP Traffic sensors for all interfaces whose SNMP traffic counters are above 0. As a result, every interface that has had traffic since the last restart of the target system is added, even if it is currently disconnected or disabled. For more information, see the Knowledge Base: How does auto-discovery with SNMP Traffic sensors work?
Knowledge Base	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?

Add Sensor

Setting	Description
Name for Traffic In Channel	For the standard channel Traffic In, enter the channel name. The sensor shows it in graphs and tables. You can change this description in the channel settings later.
Name for Traffic Out Channel	For the standard channel Traffic Out, enter the channel name. The sensor shows it in graphs and tables. You can change this description in the channel settings later.
Name for Traffic Total Channel	For the standard channel Traffic Total, enter the channel name. The sensor shows it in graphs and tables. You can change this description in the channel settings later.

Setting

Description

Name for Traffic In Channel

For the standard channel Traffic In, enter the channel name. The sensor shows it in graphs and tables.

You can change this description in the channel settings later.

Name for Traffic Out Channel

For the standard channel Traffic Out, enter the channel name. The sensor shows it in graphs and tables.

You can change this description in the channel settings later.

Name for Traffic Total Channel

For the standard channel Traffic Total, enter the channel name. The sensor shows it in graphs and tables.

You can change this description in the channel settings later.

Basic Sensor Settings

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

bandwidthsensor
snmptrafficsensor

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

Traffic Specific

Setting	Description
Interface Number	The number and name of the interface in the physical device that this sensor monitors. PRTG shows this value for reference purposes only. We strongly recommend that you only change it if the Paessler support team explicitly asks you to do so. Wrong usage can result in incorrect monitoring data.
Additional Channels	By default, each SNMP Traffic sensor creates the channels Traffic In, Traffic Out, and Traffic Total. Select additional channels for all interfaces. Click the respective channel names to mark the channels and to monitor their data: Errors in and errors out: The number of incoming and outgoing packets that could not be delivered because of errors. Discards in and discards out: The number of discarded incoming and outgoing packets even though no errors have been detected. Unicast packets in unicast packets out: The number of unicast packets that have been delivered. Non unicast packets in and non unicast packets out (32-bit only): The number of non-unicast packets that have been delivered. Multicast packets in and multicast packets out (64-bit only): The number of delivered packets that were addressed to a multicast address. Broadcast packets in and broadcast packets out (64-bit only): The number of delivered packets that were addressed to a broadcast address Unknown protocols: The number of received packets that were discarded because of an unknown or unsupported protocol. You cannot delete additional channels later. You can only disable them. If the sensor shows the Warning status with the message Channels not available, you can disable the affected channels to remove the warning.
Connection Status Handling	An interface is not operational if, for example, an Ethernet port on a switch does not have a cable plugged in. This setting is valid for all selected interfaces. Define how PRTG reacts when an interface is operational: Show down status for all disconnected states: Show the Down status for a disconnected interface. This applies every time the ifOperStatus of the interface is not "up". Show down status when disconnected, ignore when deactivated: Show the Down status for a disconnected interface only if it is not deliberately deactivated in the configuration. This applies if the ifOperStatus of the interface is not "up" and the ifAdminStatus is "up". The sensor stays in the Up status when the interface has been deactivated. Ignore all disconnected states (default): Show the Up status. Monitoring might discontinue without notice.
Alias Availability	If an alias is available for automatic port name updates. PRTG shows this value for reference purposes only. We strongly recommend that you only change it if the Paessler support team explicitly asks you to do so. Wrong usage can result in incorrect monitoring data.

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). Show in and out traffic as positive and negative area graph: Show channels for incoming and outgoing traffic as positive and negative area graph. This visualizes your traffic in a clear way. You cannot use this option in combination with manual Vertical Axis Scaling (available in the channel settings). Manual scaling is not possible if you choose this option. You cannot show a positive/negative graph for a channel if you choose to display its data in percent of maximum (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).
Show in and out traffic as positive and negative area graph: Show channels for incoming and outgoing traffic as positive and negative area graph. This visualizes your traffic in a clear way.
You cannot use this option in combination with manual Vertical Axis Scaling (available in the channel settings). Manual scaling is not possible if you choose this option.
You cannot show a positive/negative graph for a channel if you choose to display its data in percent of maximum (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
Discards In	The number of incoming discards
Discards Out	The number of outgoing discards
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.
Errors In	The number of incoming errors
Errors Out	The number of outgoing errors
Non-Unicast In	The number of incoming non-unicast packets
Non-Unicast Out	The number of outgoing non-unicast packets
Traffic In	The incoming traffic
Traffic Out	The outgoing traffic
Traffic Total	The total traffic This channel is the primary channel by default.
Unicast In	The number of incoming unicast packets
Unicast Out	The number of outgoing unicast packets
Unknown Protocols In	The number of incoming, unknown protocols