PRTG Manual: SNMP Traffic Sensor
The SNMP Traffic sensor monitors traffic on a device using the Simple Network Management Protocol (SNMP). You can create it on a device that provides traffic data. PRTG creates one traffic sensor for each individual port.
The sensor can show the following:
- Traffic in
- Traffic out
- Traffic total
You can also add additional channels:
- Errors in and out
- Discards in and out
- Unicast packets in and out
- Non-unicast packets in and out
- Multicast packets in and out
- Broadcast packets in and out
- Unknown protocols
Which channels the sensor actually shows might depend on the monitored device and the sensor setup.
SNMP Traffic Sensor
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: SNMP trafico
- You can define the displayed sensor name with port name templates in the SNMP Compatibility Options of the parent device.
- 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 device that you monitor). SNMP v1 does not support 64-bit counters, which may result in invalid data. For details, see the Knowledge Base: SNMP Traffic Sensor suddenly drops at 610Mbps
- It might not work to query data from a probe device via SNMP (querying localhost, 127.0.0.1, or ::1). Add this device to PRTG with the IP address that it has in your network and create the SNMP sensor on this device instead.
- 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 monitored device is added, even if it is currently disconnected or disabled. For details, see the Knowledge Base: How does auto-discovery with SNMP Traffic sensors work?
- 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?
The Add Sensor dialog appears when you manually add a new sensor to a device. It only shows the setting fields that are required for creating the sensor. Therefore, you will not see all setting fields in this dialog. You can change (nearly) all settings in the sensor's Settings tab later.
Select the ports on SNMP devices with multiple interfaces that you want to monitor. PRTG creates one sensor for each port that you select in the Add Sensor dialog. The settings you select will be valid for all sensors that you create when you finish this dialog.
The following settings in the Add Sensor dialog differ in comparison to the sensor's Settings tab.
Traffic Specific |
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Interface Numbers |
You see a list with the names of all items that you can monitor. Add check marks in front of the respective lines to select the desired items. You can also use the check box in the table header to select and deselect all items.
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Description "IN" Channel |
For the standard channel Traffic In, enter the channel name here. The sensor will show it in graphs and tables. You can change this description and the description of all other channels in the sensor channel settings later. |
Description "OUT" Channel |
For the standard channel Traffic Out, enter the channel name here. The sensor will show it in graphs and tables. You can change this description and the description of all other channels in the sensor channel settings later. |
Description "TOTAL" Channel |
For the standard channel Traffic Total, enter the channel name here. The sensor will show it in graphs and tables. You can change this description and the description of all other channels in the sensor channel settings later. |
On the details page of a sensor, click the Settings tab to change its settings.
Usually, a sensor connects to the IP Address or DNS Name of the parent device on which you created the sensor. See the Device Settings for details. For some sensors, you can explicitly define the monitoring target in the sensor settings. See below for details on available settings.
Basic Sensor Settings |
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Sensor Name |
Enter a meaningful 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. |
Parent Tags |
Shows Tags that this sensor inherits from its parent device, group, and probe. This setting is shown for your information only and cannot be changed here. |
Tags |
Enter one or more Tags, separated by spaces or commas. You can use tags to group sensors and use tag–filtered views later on. Tags are not case sensitive. We recommend that you use the default value. There are default tags that are automatically predefined in a sensor's settings when you add a sensor. See section Default Tags below. You can add additional tags to the sensor if you like. Other tags are automatically inherited from objects further up in the device tree. These are visible above as Parent Tags.
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Priority |
Select a priority for the sensor. This setting determines where the sensor is placed in sensor lists. A sensor with a top priority is at the top of a list. Choose from one star (low priority) to five stars (top priority). |
bandwidthsensor, snmptrafficsensor
Traffic Specific |
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Interface Number |
Shows the number and name of the interface in your physical device that this sensor monitors. This value is shown for reference purposes only. We strongly recommend that you only change it if Paessler support explicitly asks you to do so. Wrong usage can result in incorrect monitoring data! |
Additional Channels |
By default, each SNMP Traffic sensor will create the channels Traffic In, Traffic Out, and Traffic Total. Select additional channels for all selected interfaces. Click the respective channel names to mark the channels and monitor their data. You can choose between the following additional channels:
|
Connection Status Handling |
Define how PRTG will react when an interface is operational. An interface that is not operational is, for example, an ethernet port on a switch with no cable plugged in. This setting is valid for all interfaces selected above. Choose between:
|
Alias Availability |
Shows if an alias is available for automatic port name updates. This value is shown for reference purposes only. We strongly recommend that you only change it if Paessler support explicitly asks you to do so. Wrong usage can result in incorrect monitoring data! |
Sensor Display |
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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 will always be displayed underneath the sensor's name. The available options depend on what channels are available for this sensor.
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Chart Type |
Define how to show different channels for this sensor.
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Stack Unit |
This setting is only available if you select Stack channels on top of each other above. Select a unit from the list. All channels with this unit will be 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. |
By default, all of the following settings are inherited from objects that are higher in the hierarchy and should be changed there if necessary. Often, best practice is to change them centrally in the Root group's settings. For more information, see section Inheritance of Settings. To change a setting for this object only, disable inheritance by clicking the button next to inherit from under the corresponding setting name. You will then see the options described below.
Scanning Interval |
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Click |
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Scanning Interval |
Select a scanning interval (seconds, minutes, or hours). The scanning interval determines the amount of time that the sensor waits between two scans. You can change the available intervals in the system administration on PRTG on premises installations. |
If a Sensor Query Fails |
Define the number of scanning intervals that the sensor has time to reach and check a device again in case a sensor query fails. Depending on the option that you select, the sensor can try to reach and check a device again several times before the sensor will show a Down status. This can avoid false alarms if the monitored device only has temporary issues. For previous scanning intervals with failed requests, the sensor will show a Warning status. Choose from:
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Schedules, Dependencies, and Maintenance Window |
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Schedule |
Select a schedule from the list. Schedules can be used to monitor for a certain time span (days or hours) every week.
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Maintenance Window |
Specify if you want to set up a one-time maintenance window. During a maintenance window, the current sensor and all child objects will not be monitored. They will be in a Paused status instead. Choose between:
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Maintenance Begins |
This field is only visible if you enable Set up a one-time maintenance window above. Use the date time picker to enter the start date and time of the maintenance window. |
Maintenance Ends |
This field is only visible if you enable Set up a one-time maintenance window above. Use the date time picker to enter the start date and time of the maintenance window. |
Dependency Type |
Define a dependency type. You can use dependencies to pause monitoring for an object depending on the status of another object. You can choose from:
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Dependency |
This field is only visible if you enable Select a sensor above. Click the Search button and use the object selector to select a sensor on which the current sensor will depend. |
Dependency Delay (Sec.) |
This field is only visible if you enable Select a sensor above. Define a time span in seconds for dependency delay. After the master sensor for this dependency comes back to an Up status, monitoring of the dependent objects will be additionally delayed by the defined time span. This can help avoid false alarms, for example, after a server restart, by giving systems more time for all services to start up. Enter an integer value.
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Access Rights |
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Click |
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User Group Access |
Define the user groups that will have access to the selected object. A table with user groups and types of access rights is shown. It contains all user groups from your setup. For each user group, you can choose from the following access rights:
You can create new user groups in the System Administration—User Groups settings. To automatically set all objects further down in the hierarchy to inherit this object's access rights, set a check mark for the Revert children's access rights to inherited option.
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Channel Unit Configuration |
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Click |
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Channel Unit Types |
For each type of sensor channel, define the unit in which data is displayed. If defined on probe, group, or device level, these settings can be inherited to all sensors underneath. You can set units for the following channel types (if available):
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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?
Knowledge Base: SNMP Traffic Sensor suddenly drops at 610Mbps
Knowledge Base: How does auto-discovery with SNMP Traffic sensors work?
Knowledge Base: What SNMP sensors does PRTG offer?
Knowledge Base: My SNMP sensors don't work. What can I do?
To change display settings, spike filtering, and limits, switch to the sensor's Overview tab and click the gear icon of a specific channel. For detailed information, see section Sensor Channel Settings.
Click the Notification Triggers tab to change notification triggers. For detailed information, see section Sensor Notification Triggers Settings.
For more general information about settings, see section Object Settings.
For information about sensor settings, see the following sections:
