PRTG Manual: SNMP RMON Sensor
The SNMP RMON sensor monitors traffic on a device using the Remote Monitoring (RMON) standard via Simple Network Management Protocol (SNMP). It can be created on an SNMP compatible device which provides traffic data via RMON. Depending on the data returned by your device, traffic data for each port can be displayed in different channels, allowing detailed analysis.
For example, available channels for each traffic port may include Transmitted kbit/s, Packets (#/s), Broadcast Packets (#/s), Multicast Packets (#/s), CRC Errors (#/s), Undersize Packets (#/s), Oversize Packets (#/s), Fragments (#/s), Jabbers (#/s), Collisions (#/s), Packets <= 64 Byte (#/s), Packets 65 - 127 Bytes (#/s), Packets 128 - 255 Bytes (#/s), Packets 256 - 511 Bytes (#/s), Packets 512 - 1023 Bytes (#/s), Packets 1024 - 1518 Bytes (#/s), and Drop Events (#/s).
For a general introduction to the technology behind SNMP, please see Monitoring via SNMP section.
The Add Sensor dialog appears when adding a new sensor on a device manually. It only shows the setting fields that are imperative for creating the sensor. Therefore, you will not see all setting fields in this dialog. You can change all settings in the sensor's Settings tab later.
For SNMP devices with multiple interfaces multiple sensors are created at once in the Add Sensor dialog. The settings you make in this dialog are valid for all of the sensors that are created.
The following settings for this sensor differ in the 'Add Sensor' dialog in comparison to the sensor's settings page:
RMON Specific |
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Interface number |
Select the interfaces you want to add a sensor for. A list of SNMP device interfaces is shown; containing all traffic interfaces which the device provides via Remote Monitoring (RMON). In the In Use column you will see a Yes if there was already traffic detected on this interface in the past, and a No if there wasn't any traffic yet on this interface (since last device restart, usually). The In Use column does not show whether or not an interface is currently connected! One sensor will be created for each interface. You can group-select and -unselect interfaces by using the buttons Select all items and Deselect all items. |
On the sensor's details page, click on the Settings tab to change settings.
Note: If not set explicitly in a sensor's settings, it will connect to the IP Address or DNS Name defined in the settings of the parent device the sensor is created on.
Basic Sensor Settings |
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Sensor Name |
Enter a meaningful name to identify the sensor. The name will be shown by default in the device tree and in all alarms. |
Tags |
Enter one or more tags, separated by space or comma. You can use tags to group sensors and use tag-filtered views later on. Tags are not case sensitive. We recommend using the default value. You can add additional tags to it, if you like. Other tags are automatically inherited from objects further up in the device tree. Those are not visible here. |
Priority |
Select a priority for the sensor. This setting determines where the sensor will be placed in sensor lists. Top priority will be at the top of a list. You can choose from one star (low priority) to five stars (top priority). |
RMON Specific |
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Port |
Shows the number of the interface port in your physical device that this sensor is monitoring. Once a sensor is created this value cannot be changed. It is shown for reference purposes only. If you need to change this, please add the sensor anew. |
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. |
Chart Type |
Define how different channels will be shown for this sensor.
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Stack Unit |
This setting is only available if stacked graphs are selected 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. |
By default, all following settings are inherited from objects 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. To change a setting for this object, disable inheritance by clicking on the check mark symbol in front of the respective setting name. You will then see the options described below.
Scanning Interval |
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Scanning Interval |
The scanning interval determines the time the sensor waits between two scans. Select a scanning interval (seconds, minutes, or hours) from the list. You can change the available intervals in the system administration. |
Schedules, Dependencies, and Maintenance Window |
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Note: Inheritance for schedules, dependencies, and maintenance windows cannot be interrupted; the according settings from the parent objects will always be active. However, you can define additional settings here. They will be active in parallel to the parent objects' settings. |
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Schedule |
Select a schedule from the list. Schedules can be used to pause monitoring for a certain time span (days, hours) throughout the week. You can create new schedules and edit existing ones in the account settings. Note: Schedules are generally inherited. New schedules will be added to existing ones, so all schedules are active. |
Maintenance Window |
Specify if you want to set-up a one-time maintenance window. During a maintenance window this object and all child objects will not be monitored. They will enter a paused state then. Choose between:
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Maintenance Begins At |
This field is only visible if maintenance window is enabled above. Use the date time picker to enter the start date and time of the maintenance window. |
Maintenance End At |
This field is only visible if maintenance window is enabled above. Use the date time picker to enter the end date and time of the maintenance window. |
Dependency Type |
Define a dependency type. Dependencies can be used to pause monitoring for an object depending on the status of another. You can choose between:
Note: Testing your dependencies is easy! Simply choose 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. |
Dependency |
This field is only visible if the select object option is enabled above. Click on the reading-glass symbol and use the object selector to choose an object on which the current sensor will be dependent on. |
Delay (Seconds) |
Define a time span. After the master object for this dependency comes back to an Up status, monitoring of the depending 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 in seconds. Note: This setting is not available if you choose this sensor to be the Master object for parent. In this case, please define delays in the parent Device Settings or the superior Group Settings. |
Access Rights |
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User Group Access |
Define which user group(s) will have access to the object you're editing. A table with user groups and right 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. |
Channel Unit Configuration |
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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):
Note: Custom channel types can be set on sensor level only. |
Click on the Channels tab to change display settings, spike filter, and limits. For detailed information, please see Sensor Channels Settings section.
Click on the Notifications tab to change notification triggers. For detailed information, please see Sensor Notifications Settings section.
For more general information about settings, please see Object Settings section.
For information about sensor settings, please see the following sections:
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