PRTG Manual: QoS (Quality of Service) Round Trip Sensor

Sensor Name

Enter a name to identify the sensor.

Parent Tags

Shows tags that the sensor inherits from its parent device, parent group, and parent probe.

This setting is for your information only. You cannot change it.

Tags

Enter one or more tags. Confirm each tag with the Spacebar key, a comma, or the Enter key. You can use tags to group objects and use tag-filtered views later on. Tags are not case-sensitive. Tags are automatically inherited.

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

For performance reasons, it can take some minutes until you can filter for new tags that you added.

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

• qossensor

Priority

Select a priority for the sensor. This setting determines the position of the sensor in lists. The highest priority is at the top of a list. Choose from the lowest priority () to the highest priority ().

Timeout (Sec.)

Enter a timeout in seconds for the request. Enter an integer. The maximum timeout value is 900 seconds (15 minutes).

If the reply takes longer than this value, the sensor cancels the request and shows a corresponding error message.

QoS Target

Define the type of target that receives the UDP packets:

• PRTG probe (recommended): Use a probe as the connection endpoint.
• Custom target: Use the PRTG QoS Reflector as the connection endpoint.

For more information about the QoS Reflector, see the Knowledge Base: How can I monitor QoS round trips without using remote probes?

Target Probe

This setting is only visible if you select PRTG probe (recommended) above. Define the target probe that receives the UDP packets. The dropdown list shows all local probes and remote probes in your setup.

If you want to run the sensor on the local probe, select a remote probe as the Target Probe. If no remote probe is available, install and connect a remote probe first. Alternatively, you can use the PRTG QoS Reflector.

If you want to run the sensor on a remote probe, select either a different remote probe or the local probe as the target. The sensor measures values for the network track between the parent probe and the target probe.

You must ensure that firewalls or network address translation (NAT) rules allow UDP packets to reach the target probe. The probe automatically opens the Windows firewall on the target system. For details, see the Knowledge Base: What connection settings are necessary for the QoS (Quality of Service) Round Trip sensor?

In PRTG Hosted Monitor, you can only select a different remote probe as the target probe. QoS measurements for connections to the hosted probe are not possible.

Target Host/IP Address

Define the IP address of the QoS target:

• If you use the QoS Reflector, enter the address of the system on which the reflector script runs.
• If you use a probe, enter the address of the probe to which the source probe connects.

If you do not use NAT rules, this is usually the IP address in parentheses next to the probe name under Target Probe.

Port

Define the source and target port for the UDP packets. Both the source probe and the target probe use this port. Enter an integer. The default port is 50000. PRTG supports the port numbers 1024-65536 for UDP packets.

Use a different port for each QoS (Quality of Service) Round Trip sensor to make sure that packets can be assigned correctly.

The port must be available on both the source system and the target system.

Number of Packets

Define the number of packets that the sensor sends with each scanning interval. Enter an integer. The default value is 1000. The minimum value is 10. The maximum value is 1000.

We recommend that you use the default value.

Packet Size (Bytes)

Define the size of the packets in bytes that the sensor sends. Enter an integer. The default value is 172. The minimum value is 172. The maximum value is 4500.

We recommend that you use the default value.

Packet Delay (ms)

Define the time in milliseconds (ms) that the sensor waits between two packets. Enter an integer. The default value is 20. The minimum value is 10. The maximum value is 1000.

We recommend that you use the default value.

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 is always displayed 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 different channels are shown for this sensor:

• 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).

Stack Unit

This setting is only visible if you enable Stack channels on top of each other as Graph Type. Select a unit from the list. All channels with this unit are 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.

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 in percent.

Jitter Average

The average jitter in in milliseconds (msec)

Jitter Max

The maximum jitter in msec

This channel is the primary channel by default.

Jitter Min

The minimum jitter in msec

MOS

The mean opinion score (MOS)

Packet Delay Variation Average

The average packet delay variation in msec

Packet Delay Variation Max

The maximum packet delay variation in msec

Packet Delay Variation Min

The minimum packet delay variation in msec

Packets Corrupted

The corrupted packets in percent

Packets Duplicated

The duplicated packets in percent

Packets Lost

The lost packets in percent

Packets Out Of Order

The out of order packets in percent

RTT (Average)

The average round-trip time (RTT) in msec

RTT (Maximum)

The maximum RTT in msec

RTT (Minimum)

The minimum RTT in msec