PRTG Manual: SNMP Traffic Sensor

Interface Number

You see a list with the names of all items that are available to monitor. Add check marks in front of the respective lines to select the desired items. PRTG creates one sensor for each selection. You can also use the check box in the table head to select and deselect all items.

You can see the connection status of an interface in the respective table column.

You can select and deselect interfaces by using the buttons Select all connected interfaces, Select all disconnected interfaces, and Deselect all interfaces.

Description "IN" Channel

For the standard channel Traffic In, enter the channel name here. The sensor shows 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 shows 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 shows it in graphs and tables. You can change this description and the description of all other channels in the sensor channel settings later.

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.

It is not possible to enter tags with a leading plus (+) or minus (-) sign, nor tags with round parentheses (()) or angle brackets (<>).

Priority

Select a priority for the sensor. This setting determines where the sensor is placed in sensor lists. Top priority is at the top of a list. Choose from one star (low priority) to five stars (top priority).

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. Choose additional channels for all selected interfaces. Click on the respective channel name(s) to mark them and monitor their data.

You can choose from the following additional channels:

• Errors In & Out: The number of in-/outbound packets that could not be delivered because of errors.
• Discards In & Out: The number of discarded in-/outbound packets even though no errors had been detected.
• Unicast Packets In & Out: The number of unicast packets that were delivered.
• Non Unicast Packets In & Out (32-bit only): The number of non-unicast packets that were delivered.
• Multicast Packets In & Out (64-bit only): The number of delivered packets that were addressed to a multicast address.
• Broadcast Packets In & 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.

Additionally created channels cannot be deleted later. You can only disable them.

If the sensor shows a Warning status with the message Channels not available, you can disable affected sensor channels here to remove the warning.

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 from:

• Show alarm for all "disconnected" states: The sensor for the interface will always turn into a Down status for a disconnected interface. This applies if the ifOperStatus of the interface is not "up".
• Show alarm when disconnected, but ignore when deactivated: The sensor will turn into a 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". So the sensor will keep the Up status when the interface has been deactivated.
• Ignore all "disconnected" states: The sensor will not show an alarm and the Up status will persist.
  Monitoring will be discontinued without notice.

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!

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.

You can set another primary channel later by clicking on the pin symbol of a channel in the sensor's Overview tab.

Chart Type

Define how to show different channels for this sensor.

• Show channels independently (default): Show an own 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 will generate an easy-to-read 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 Sensor Channel Settings). Manual scaling is not possible if you choose this option.
• Show in and out traffic as positive and negative area chart: Show channels for incoming and outgoing traffic as positive and negative area chart. This will visualize your traffic in a clear way.
  You cannot use this option in combination with manual Vertical Axis Scaling (available in the Sensor Channel Settings). Manual scaling is not possible if you choose this option.
  You cannot show a positive/negative chart for a channel if you choose to display its data in percent of maximum (available in the Sensor Channel Settings).

Stack Unit

This setting is only available if you choose Stack channels on top of each other above. Choose 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.

Click to disrupt the inheritance. See section Inheritance of Settings for more information.

Scanning Interval

Select a scanning interval (seconds, minutes, or hours) from the list. The scanning interval determines the time 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 a sensor has time to reach and check a device again in case a sensor query fails. The sensor can try to re-reach and check a device several times, depending on the option you select here, before it will be set to a Down status. This helps you avoid false alarms if the monitored device has only temporary issues. For previous scanning intervals with failed requests, the sensor will show a Warning status. Choose from:

• Set sensor to down immediately: The sensor will show an error immediately after the first failed request.
• Set sensor to warning for 1 interval, then set to down (recommended): After the first failed request, the sensor will show a warning status. If the following request also fails, the sensor will show an error.
• Set sensor to warning for 2 intervals, then set to down: Show an error status only after three consecutively failed requests.
• Set sensor to warning for 3 intervals, then set to down: Show an error status only after four consecutively failed requests.
• Set sensor to warning for 4 intervals, then set to down: Show an error status only after five consecutively failed requests.
• Set sensor to warning for 5 intervals, then set to down: Show an error status only after six consecutively failed requests.

Sensors that monitor via Windows Management Instrumentation (WMI) always wait at least one scanning interval until they show an error. It is not possible to set a WMI sensor to Down immediately, so the first option will not apply to these sensor types. All other options can apply.

If a sensor has defined error limits for channels, it will always show a Down status immediately, so no "wait" option will apply.

If a channel uses lookup values, it will always show a Down status immediately, so no "wait" options will apply.

Inheritance for schedules, dependencies, and maintenance windows cannot be interrupted. The corresponding settings from the parent objects will always be active. However, you can define additional settings here. They will be active at the same time as the parent objects' settings.

Schedule

Select a schedule from the list. Schedules can be used to monitor for a certain time span (days, hours) every week. With the period list option it is also possible to pause monitoring for a specific time span. You can create new schedules and edit existing ones in the account settings.

Schedules are generally inherited. New schedules will be added to existing ones, so all schedules are active at the same time.

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:

• Not set (monitor continuously): No maintenance window will be set and monitoring will always be active.
• Set up a one-time maintenance window: Pause monitoring within a maintenance window. You can define a time span for a monitoring pause below and change it even for a currently running maintenance window.

To terminate a current maintenance window before the defined end date, change the time entry in Maintenance Ends to a date in the past.

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:

• Use parent: Use the dependency type of the parent device.
• Select a sensor: Use the dependency type of the parent device. Additionally, pause the current sensor if another specific sensor is in a Down status or in a Paused status caused by another dependency. Select below.
• Master sensor for parent: Make this sensor the master object for its parent device. The sensor will influence the behavior of its parent device: If the sensor is in a Down status, the device will be paused. For example, it is a good idea to make a Ping sensor the master object for its parent device to pause monitoring for all other sensors on the device in case the device cannot even be pinged. Additionally, the sensor will be paused if the parent group is paused by another dependency.

Testing your dependencies is easy! Simply select Simulate Error Status from the context menu of an object that other objects depend on. A few seconds later, all dependent objects should be paused. You can check all dependencies in your PRTG installation by selecting Devices | Dependencies from the main menu bar.

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. Please enter an integer value.

This setting is not available if you set this sensor to Use parent or to be the Master sensor for parent. In this case, please define delays in the parent Device Settings or in its parent Group Settings.

Click to disrupt the inheritance. See section Inheritance of Settings for more information.

User Group Access

Define which user group(s) will have access to the object you're editing. 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:

• Inherited: Use the access rights settings of the parent object.
• None: Users in this group cannot see or edit the object. The object neither shows up in lists nor in the device tree. Exception: If a child object is visible to the user, the object is visible in the device tree, though not accessible.
• Read: Users in this group can see the object and review its monitoring results.
• Write: Users in this group can see the object, review its monitoring results, and edit the object's settings. They cannot edit access rights settings.
• Full: Users in this group can see the object, review its monitoring results, edit the object's settings, and edit access rights settings.

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.

For more details on access rights, see section User Access Rights.

Click to disrupt the inheritance. See section Inheritance of Settings for more information.

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):

• Bandwidth
• Memory
• Disk
• File
• Custom

Custom channel types can be set on sensor level only.