Monitor quality of service (QoS) with PRTG

...and suddenly, delays are a thing of the past


  • QoS monitoring included

  • Cisco monitoring included

  • Alarm system included

  • PRTG monitors jitter, packet loss, latency, and MOS

  • PRTG provides for
    stable VoIP


Free Download

Unlimited version of PRTG for 30 days. After 30 days, PRTG reverts to a free version.
Or, you can upgrade to a paid license anytime.


The PRTG QoS Tool


 i What is a sensor?

In PRTG, “sensors” are the basic monitoring elements. One sensor usually monitors one measured value in your network, e.g. the traffic of a switch port, the CPU load of a server, the free space of a disk drive. On average you need about 5-10 sensors per device or one sensor per switch port.

View video (3:26 min.)


Five PRTG sensors for testing and measuring quality of service:

QoS One Way Sensor

QoS (Quality of Service) One Way Sensor

The QoS (Quality of Service) One Way Sensor measures the quality of service of the data line between two devices. For it to work, you'll need to install a remote probe on or near the second device.

QoS Roundtrip Sensor

QoS (Quality of Service) Round Trip Sensor

The QoS (Quality of Service) Round Trip Sensor measures quality of service across an entire path, i.e. the round trip of a data packet. The round-trip time is displayed in milliseconds. You can use the PRTG QoS Reflector with this sensor as an alternative to a remote probe. 

Cisco IP-SLA Sensor

Cisco IP SLA Sensor

Many Cisco devices determine QoS values by themselves. With the Cisco IP SLA Sensor, you can read these values and incorporate them into your monitoring. This sensor is included at no extra charge! More on Cisco IP SLA monitoring.

SNMP Cisco CBQoS Sensor

SNMP Cisco CBQoS Sensor

The SNMP Cisco CBQoS Sensor displays additional data per category, both before and after the creation of QoS guidelines. To do so, it uses Cisco’s Class-Based Quality of Service. With this sensor, data is queried via SNMP. More on SNMP monitoring.

 i SNMP stands for Simple Network Monitoring Protocol. Its usefulness in network administration comes from the fact that it allows information to be collected about network-connected devices in a standardized way across a large variety of hardware and software types. SNMP is a protocol for management information transfer in networks, for use in LANs especially, depending on the chosen version.
Read more

Ping Jitter Sensor

Ping Jitter Sensor

The Ping Jitter Sensor calculates jitter for a set of ping signals. You can use ping monitoring to monitor the availability of all your network devices.

Ping Jitter Sensor

Custom sensors

PRTG comes with more than 250 preconfigured sensors. It also lets you create your own custom sensors. During installation, you can choose to have the Auto Discovery feature run automatically. PRTG uses ping to gather information on your network devices and immediately set up your initial monitoring.


A sneak peek at the QoS monitor PRTG



Quality of service: 3 key questions and answers

What is quality of service?

Quality of service refers to the quality of a communication service from the point of view of the user. Both the establishment of the connection and the connection communication should be stable, with data packets transmitted free of errors and in their entirety. Quality of service is an extremely important consideration, especially for companies.

How do you measure quality of service?

Quality of service is measured by four main parameters: packet loss, delay time (latency), deviation (jitter), and the mean opinion score. These four parameters, among others, are measured by PRTG and must fall within specific threshold values to ensure quality of service does not suffer.

How can I achieve a high quality of service?

As an administrator, it’s your job to monitor and optimize your company’s quality of service. If transmission errors occur, you must be able to quickly identify the problem. To do so, you’ll need QoS software or a QoS program that monitors quality of service and promptly notifies you in the event of disruptions.


Free Download

Unlimited version of PRTG for 30 days. After 30 days, PRTG reverts to a free version.
Or, you can upgrade to a paid license anytime.



Monitoring QoS: The 4 main parameters


Packet loss

QoS parameter 1: Packet loss

When it comes to quality of service, packet loss plays a vital role. Packets can get lost, or arrive as duplicates or in the wrong order. PRTG captures all three of these scenarios. As a result, administrators can quickly uncover the source of the error. Packet loss may be caused by network overloads, poorly performing devices, or hardware/software errors. More on packet loss.


QoS parameter 2: Latency

Latency (latency time) also plays an important role in real-time communication. Latency is the amount of time a packet needs to be sent to its recipient and then back to its sender again. Even the smallest delay can have an immediate effect on the quality of the transmission. More on latency monitoring.


QoS parameter 3: Jitter

Jitter is the deviation in the transmission time of a data packet. If jitter buffers are used by the receiver, then certain amounts of jitter are still acceptable from the point of view of the user. As an administrator, you need to be quickly informed of jitter so you can step in and take action at once. More on jitter monitoring.

Mean opinion score (MOS)

QoS parameter 4: Mean opinion score (MOS)

The mean opinion score (MOS) measures the overall quality of voice and image transmissions. It is the average of several valuation parameters. The worst MOS value is 1 (impossible to understand the person on the line despite great effort), while the highest value is 5 (no effort required to understand the voice on the other end of the line).


“We can all work with greater peace of mind knowing
that our systems are constantly being monitored.”

Markus Puke, Network Administrator, Schüchtermann Klinik, Germany


Trusted by 500,000 users and recognized
by industry analysts as a leader

“Fantastic network and infrastructure monitoring solution that is easy to deploy and easier still to use. Simply the best available.”

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“Software is absolutely perfect, Support is superior. Meets all needs and requirements, This is a must have solution if you are needing any form of monitoring.”

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“The tool excels at its primary focus of being a unified infrastructure management and network monitoring service.”

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Keep a constant eye on your network –
even while on the go

PRTG can be started within minutes and it's compatible with many mobile devices.


PRTG comes with all the features you need, plus more your IT infrastructure won't want to live without.


PRTG monitors these vendors and applications, and more, in one view!



Free Download

Unlimited version of PRTG for 30 days. After 30 days, PRTG reverts to a free version.
Or, you can upgrade to a paid license anytime.



QoS recommendations: ITU-T vs. PRTG

The ITU-T recommends:

The International Telecommunication Union (ITU-T) is responsible for telecommunications standards. It provides several recommendations with regard to quality of service. For example: packet loss should be no higher than 5%, while with latency, delays of 125 milliseconds or less are still acceptable.

PRTG recommends:

PAESSLER AG is considerably stricter than the ITU-T. PRTG recommends a packet loss rate of 0%, and maximum latency and jitter values of 100 and 25 milliseconds, respectively. Thanks to such stringent requirements, you can quickly become aware of disruptions – and get to work on them at once. 


Free Download

Unlimited version of PRTG for 30 days. After 30 days, PRTG reverts to a free version.
Or, you can upgrade to a paid license anytime.



3 good reasons to choose PRTG

Comprehensive monitoring

Comprehensive monitoring

PRTG lets you keep an eye on your entire IT infrastructure – not just your quality of service. With PRTG, you no longer need a slew of individual monitoring programs that run concurrently and require their own separate maintenance. Instead, you can enjoy a high-performance, all-in-one monitoring tool that covers your entire IT environment.

All features included

All features included

With a license, you get access to the full range of PRTG features. In other words: all sensors and apps, the notification system, and support are included. PRTG is a reliable investment for ensuring the quality and security of your network. More than 500,000 administrators worldwide put their trust in PRTG.  

Stable VOIP

Stable VoIP

PRTG lets you control your quality of service, which includes the quality of your VoIP.  Your coworkers will have one less reason to call the help desk and can therefore stay focused on their jobs. This saves both time and worry. And in the event of disruptions, you’ll be alerted at once – before others notice something is up.


Practical tip: “Hey Konstantin, what can I do with the PRTG QoS Reflector?”

“When using our QoS (Quality of Service) Round Trip Sensor, you usually need to place a remote probe on a second Windows computer to measure the round-trip values of data packets. With the PRTG QoS Reflector, this is no longer necessary. The Reflector is a Python script that sends data packets from the endpoint back to PRTG. The QoS Reflector also runs on all Linux systems, even a small Raspberry Pi.”

Konstantin Wolff, Software Developer at Paessler AG



PRTG The Swiss Army knife

PRTG: The Swiss Army knife for sysadmins

Adapt PRTG individually and dynamically to your needs relying on a strong API:

  • HTTP API: Access monitoring data and manipulate monitoring objects using HTTP requests
  • Custom Sensors: Create your own sensors for customized monitoring
  • Custom Notifications: Create your own notifications to send alarms to external systems
  • REST Custom Sensor: Monitor almost everything that provides XML or JSON


Over 95% of our customers recommend PRTG


Paessler AG worldwide trialled PRTG in over 600 IT departments.
The aim was to tune the network monitoring software closer to the needs of the administrators.
The result of the survey: over 95% of the participants would recommend PRTG - or already had.

Recommend PRTG



Network Monitoring Software - Version (December 1st, 2021)


Download for Windows and cloud-based version PRTG Hosted Monitor available


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