<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: Passive Application Performance Sensor
The Passive Application Performance sensor monitors Transport Control Protocol (TCP) connection timings using packet sniffer. It can measure the performance of many different web applications without actually having direct access to neither the client nor the server. To obtain valuable data, these applications must work TCP-based and initiate a new session with each request.
The sensor can show the following:
- Total number of packets per second on the selected network card
- Number of dropped packets per second by PRTG because of system overload (more processor power is required if this value is above zero to cope with the traffic)
- Number of currently active connections on all monitored applications.
For defined applications, the sensor can show (together with the corresponding application name):
- Request time in msec: average time between the initial (SYN) packet from the client and the first request package from the client
- Response time in msec: average time between the initial (SYN) packet from the client and first packet of the result from the server
- ACK (acknowledge) time in msec: average time between the initial (SYN) packet of a connection from the client until the server sends an ACK (acknowledge) packet. This means that a TCP connection was successfully established (in LANs this value is zero in most cases and only increases for extreme loads).
- Count: total number of observed connections to the service in the last monitoring interval. This is the number of measurements the average is based on. The higher the value the more reliable/averaged the data is. If this value is zero, PRTG did not see any packets for this service.
Passive Application Performance Sensor
Click here to enlarge: http://media.paessler.com/prtg-screenshots/passive_application_performance.png
- Important notice: Currently, this sensor type is in beta status. The methods of operating can change at any time, as well as the available settings. Do not expect that all functions will work properly, or that this sensor works as expected at all. Be aware that this type of sensor can be removed again from PRTG at any time.
- For a general introduction to the technology behind packet sniffing, please see manual section Monitoring Bandwidth via Packet Sniffing.
- Note: This sensor type can have a high impact on the performance of your monitoring system. Please use it with care! We recommend using not more than 50 sensors, on each probe, of this type of sensor.
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.
On the details page of a sensor, click on the Settings tab to change its settings.
Note: Usually, a sensor connects to the IP Address or DNS Name of the parent device on which you created this sensor. See section Device Settings for details. For some sensor types, you can define the monitoring target explicitly in the sensor settings. Please see below for details about 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, and in alarms, logs, notifications, reports, maps, libraries, and tickets. |
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 is placed in sensor lists. Top priority is at the top of a list. You can choose from one star (low priority) to five stars (top priority). |
Applications |
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Network Adapter |
Select the network adapter you want to monitor. |
Applications |
Define the applications you want to monitor. For each application, use one dedicated line. Use the following syntax to define an application to be monitored: ip:port=application. Provide the IP address and port number of the application. Behind the equals sign, enter a name for the application which will be displayed in the channels. Please enter a string. This sensor will create four sensor channels with the application name, for example, "Application (ACK)". |
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. Note: 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 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 |
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. |
When a Sensor Reports an Error |
Define the number of scanning intervals a sensor has to report an error until the sensor will be set to a Down status. The sensor can try reaching a device several times, depending on your setup you can specify here, to help 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 between:
Note: 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 "down" immediately, so the first option will not apply to these sensor types (all other options can apply). Note: If a sensor has defined error limits for channels, this sensor will always be set to a Down status immediately, so no "wait" option will apply. Note: If a channel uses lookup values, the sensor will always be set to a Down status immediately, so no "wait" options will apply. |
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 monitor for a certain time span (days, hours) throughout the 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. 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:
Note: To terminate a current maintenance window before the defined end date, you can change the time in Maintenance End At field to a date in the past. |
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. 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 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. For more details about access rights, please see section User Access Rights. |
To change display settings, spike filter, and limits, switch to the sensor's Overview tab and click the gear icon of a specific channel. For detailed information, please see Sensor Channels Settings section.
Click 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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