VoIP Monitoring
Software PRTG


  • QoS Monitoring & IP SLA Monitoring. All in one.
  • PRTG monitors the VoIP quality and runs VoIP latency tests.
  • PRTG alerts you before phone errors occur.


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100 Sensors, perfect for small networks



PRTG's predefined QoS Round Trip Sensor measures the Quality of Service of your lines. Some of the parameters covered by this sensor are latencyjitterpacket loss, duplicate packets, and the Mean Opinion Score (MoS). This sensor is included free of charge! There are no hidden costs. On the contrary - take advantage of this sensor along with the other 100 free sensors for as long as you use PRTG. 


Higher-priced Cisco switches and routers have a built-in monitoring tool, or so-called IP SLA monitoring. Among other things, IP SLA monitoring measures the quality of your service. PRTG provides a preconfigured Cisco IP SLA Sensor for this purpose. With this sensor, PRTG lets you monitor your Cisco device data - at no extra charge - as part of the 100 free sensors that you can use to get started. You may also choose to use it as part of your license, and thereby simplify the calculation of your purchase cost.


PRTG's alarm feature runs discreetly in the background and focuses on that which is most important. Notifications are customizable according to your needs. Decide when alerts should be sent, and the way you would like to receive them: by email, SMS, or page. As an IT manager, you can rest assured that you will be notified of issues promptly, before emergencies crop up. This alarm feature is likewise included!


Thanks to the dashboard designer, you can create your own personal dashboard - and keep a constant eye on your entire monitoring environment. For inspiration, see some examples of dashboards from our users. Even while on the go, you'll enjoy a constant overview by way of our app, which is available for Android, iOS, and Windows phones.


PRTG is more than "just" a VoIP monitoring tool. It also lets you monitor, among other things, your bandwidthLANservers, and CPU. PRTG is an all-in-one solution. Once it is configured, your monitoring is good to go, and you can confidently go about your work. It is easy to see why so many of our customers love our tool!





Voice over Internet Protocol (VoIP)

VoIP has become the telephony standard in medium-sized companies and groups. Every VoIP call saves money. VoIP software is easier to configure and more versatile. The voice is digitized, then sent across the network connection and reassembled. This process, however, is prone to malfunctions. Some examples: packets arrive too late, as duplicates, or in the wrong order...

QoS Monitoring

With QoS monitoring, data line performance is monitored using parameters such as latency, packet loss, and jitter. QoS monitoring can take place internally, i.e. as inside a large building (the company LAN). Otherwise, the connection to external offices in other locations can be monitored if the latter are equipped with remote probes suitable for VoIP monitoring. More information on Quality of Service monitoring.


For IP SLA monitoring, first you must properly configure your Cisco devices, and then add them to PRTG. Be sure to enable SNMP access, for data will be queried via this protocol. In the second step, create the appropriate IP SLA sensor and follow the subsequent instructions. The first data will arrive in no time at all. More information on IP SLA.



PRTG can be installed within minutes and it's compatible with most mobile devices.

Andreas Reimann

“The support we received from Paessler AG was extremely reassuring. Their reaction time, know-how, and solutions were outstanding in every department.”

Andreas Reimann, Senior Networking Communication Architect at Zürich Airport. Zürich Airport uses more than 4,500 sensors for its monitoring. To the case study (german)

PRTG simplifies your day

Our monitoring software works for you and promptly notifies you of potential issues.
It frees you to concentrate on your day-to-day tasks with peace of mind.


PRTG is quick to report complications - before the onset of crashes. For you, this results in less work and greater savings. And by keeping a constant eye on latency, packet loss, and other parameters, you'll also optimize the quality of your VoIP calls. 


Setting up PRTG takes no time at all. 200+ predefined sensors provide for comprehensive network monitoring.  PRTG comes equipped with several VoIP sensors, including those designed for Cisco devices. Initial monitoring is set up automatically during installation.


80% of our customers report substantial or even exceptional network management cost savings. Our customers report that their PRTG licenses have paid for themselves in an average of 3 ½ months.

PRTG – Smart Setup

by Kimberley, Product Evangelist

Here we show you the first steps with PRTG: from the installation to the initial configurations, we explain how easy PRTG works and how the software is built.

View video (16:11 Min., english)

Frustrated with your current monitoring software? A tip for those making the switch

Do you currently use Nagios or other commercial monitoring software? Frustrated with awkward user interfaces and hidden costs? Then make the quick and easy switch to PRTG. Our Smart Setup is extremely user-friendly. Installation takes a few short minutes. Preconfigured sensors are automatically created during setup - another free PRTG feature. 




When calling, perhaps the following are true: There is static on the line. There are delays. There are echoes.

If so, then you have a problem with the quality of your VoIP service. Take advantage of the parameters below to measure performance.

Latency: Latency measures the time data packets need to travel from the sender to the recipient. According to ITU-T, which is responsible for telecommunications standards within the International Telecommunications Union, delays should not exceed 125 milliseconds. When it comes to latency, PRTG recommends a maximum delay of 100 milliseconds, in order that you may be notified sufficiently in advance and can react before noticeable disruptions occur.

Packet losses: Packet loss is one of the most frequent errors to take place during VoIP, as well as during video conferences and streaming. ITU-T recommends a maximum loss rate of 5 percent. For packet losses, PRTG recommends a default setting of 0%. For even the smallest losses can cause interruptions. PRTG also lets you know if packets are "duplicates" or "out of order."  

Jitter: Jitter is also an important parameter for determining your quality of service. Jitter measures the deviation from the average latency value. PRTG recommends that this deviation be less than 20 to 25 milliseconds. This value, too, lies significantly below the ITU-T recommendation.

Mean Opinion Score (MOS): The MOS rates the call quality on a scale of 1 to 5. The higher the score, the better the quality. The rating is based on jitter, latency, and other parameters. MOS is a kind of summary that is displayed in the sensor overview with the other key information.

The Swiss Army knife for admins


Adapt PRTG individually and dynamically, to your specific needs, using the 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

150,000 administrators worldwide trust in our software.



Quote Stefan Linke

Praxis-Tipp: "Practical tip: “Hey Stephan, do you have any tips for VoIP monitoring? ”"

“To simulate a telephone that uses the same network as your real IP telephone, simply set up our QoS Reflector Script on a Raspberry Pi and connect the latter to the desired point on the network. By doing so, you can guarantee that you are measuring the right network path with our QoS Round Trip Sensor. This is important because VoIP traffic is usually treated with priority.”

Stephan Linke works in the PAESSLER AG Technical Support department.

Award winning solution

We work hard on making our software as powerful and easy-to-use
as possible for our customers each and every day.
Of course it makes us proud when we get awards for that.




  • QoS Round Trip Sensor: The QoS Roundtrip Sensor monitors the quality of the network connection while taking QoS parameters such as latency, packet loss, and jitter into consideration. Read more about the QoS Roundtrip Sensor here.
  • QoS One Way Sensor: The QoS One Way Sensor monitors the quality of the network connection between two probes. Find out more about the QoS One Way Sensor here.
  • Cisco IP SLA Sensor:

    This sensor takes advantage of the ability of Cisco devices, which feature IP SLA, to read and analyze data. Find out more about the Cisco IP SLA Sensor here.

  • SNMP Cisco CBQoS Sensor: Even Cisco devices with CBQoS can be monitored with their own special sensor. Find out more about the SNMP Cisco CBQoS Sensor here.


Made in Germany: The PRTG Network Monitoring Tool is the fruit of an engaged team. The company was founded by Dirk Paessler. PESSLER AG's headquarters are located in the city of Nuremberg, in the heart of Germany. We combine typical German virtues such as high quality standards, industriousness, and commitment with international, cosmopolitan flair. Read more about our firm here. By the way: We are regularly looking for new recruits.

Case Studies: Airports, utility companies, banks, colleges, hospitals: PRTG is present in every industry. For each of our customers, business and organizational processes depend on the proper functioning of the network infrastructure. PRTG's customer satisfaction is close to 100%. Read in our case studies how our customers use PRTG.

Product tests: It goes without saying that we are convinced by the quality of PRTG. But what about the others? PRTG has always performed extremely well in tests. PRTG user "LanLine" sums it up best: "PRTG was already good several years ago, and has gotten better from version to version ever since." Such has been our steadfast and sincere goal. Read more about monitoring software product tests and comparisons here.

Support: Our support team works hard every day to help customers solve their monitoring problems. Our goal is to resolve all inquiries within 24 hours (on business days). We've drafted a comprehensive manual and built up an extensive knowledge base featuring videos, webinars, and FAQs. All support, of course, is also included!

Getting started is easy: The first 100 PRTG sensors are free, allowing you to evaluate our monitoring tool with no strings attached. For small companies, these 100 sensors are already enough for emergency monitoring. To upgrade, simply search for a suitable license. You can modify your license any time you like. 


Download Network Monitoring Software for Windows - Version (April 18th, 2017)
Languages English, German, Spanish, French, Portuguese, Dutch, Czech, Russian, Japanese, and Simplified Chinese
Pricing Free for up to 100 sensors (Price List)
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