What Is QoS on a Router & Do You Need It?

Quality of Service, better known as QoS, is a feature that allows you to prioritize different kinds of Internet traffic or services. The result is, usually, a performance improvement for the most important activities and a bit of waiting for the less important ones.
What Is QoS on a Router & Do You Need It

After extensive testing and research, we have put together this article that explores in detail how QoS might help (or hinder) your browsing experience.

Keep reading to learn more.

What is QoS?

Imagine you are at home, getting ready for a job interview via Zoom. You sit down, greet the interviewer, and before he can even get started—your call drops.

You re-join, but your video is frozen, and the audio is out of sync. After a couple of minutes, the interviewer says it’s better if you reschedule. Ouch.

What happened? 

As you go out, your roommate yells, “I’m downloading the whole Lord of the Rings trilogy; want to watch it?

Cue chaos.

These are the type of situations Quality of Service (QoS) aims to solve. 

With QoS, your router identifies different types of traffic and prioritizes what’s most important to you [1]. 

You can set up categories like videoconferencing, gaming, and VoIP calls to be above any other type of traffic. 

This way, your router will ensure those activities have all the bandwidth they need to work without interruptions before using it for anything else [2].

Let’s go back to the example above, with QoS enabled this time.

If you had set up QoS in your router, with video conferencing as a priority, your call would have been flawless. However, your roommate might have complained that his movies are downloading slowly.

Instead of sharing it half and half, your router would have made sure you had enough bandwidth for your call to work correctly. Only then will it give some to your roommate for his download.

As we can see, some types of traffic are usually more critical than others. Your friend would’ve been fine if the download took an extra half an hour. But video calls cannot wait. 

It’s not always black and white, though.

If you don’t really need it, QoS could hinder your performance instead of making it better. You will need to confirm that QoS will help before setting it up on your router.

Do You Need QoS?

Not always. If your bandwidth is enough, QoS won’t offer any real improvements.

Adding to that, incorrectly setting up QoS will actually result in a performance decrease.

However, if you are facing a problem that QoS can help solve, the performance boost can be significant. Let’s expand some more.

As we said above, having enough bandwidth is a good reason to skip QoS. Here’s an example:

You have a 1000 Mbps (1 Gbps) internet connection, and your priority is videoconferencing. You set up QoS to prioritize video calls. And limit file downloads so they can only use 200 Mbps.

Let’s say you are in a multi-user videoconference that is taking up 300 Mbps of your bandwidth. You are also downloading a large 200 GB file simultaneously, which you need later today. 

In this case, out of your 1000 Mbps connection, only 500 Mbps total are being used. 

300 Mbps are used for the video call, and 200 Mbps for the download.

Your video call is already using everything it needs; there’s no way to assign more to it simply because it doesn’t need it.

On the other hand, your file is being throttled to 200 Mbps. Making the download take significantly longer, for no apparent reason. 

As you can see, turning on QoS is not always the best move. 

You will need to have a good understanding of your bandwidth requirements in order to utilize QoS effectively.

Types of QoS

There are different ways to set up QoS depending on what your router allows.

By Device:

On the lower end of the QoS offering is filtering by device. This is the type of QoS you will find in budget routers

It’s as simple as it sounds.

You let your router know which devices will connect to it (usually through their IP address) and assign a priority to each of them.

The highest priority device will always have dibs on your bandwidth. And only after fulfilling its needs will your router assign bandwidth to lower priority devices.

By Service:

Similar to our example at the beginning, you might want to prioritize video conferencing above anything else, regardless of what device you are using.

You could also set up services like streaming, VoIP calls, gaming, or torrents as the top priority.

By Application:

On the higher end of the spectrum, you’ll find devices that can even prioritize traffic by application [3]. Here you could, for example, set up Netflix as the highest priority and YouTube as the lowest.

This way, your Netflix feed will always be fluid and high definition, while your kid’s YouTube videos might buffer if there is not enough bandwidth. 

How Does My Router Know What Is What?

That depends on how you set up QoS.

As we learned, some routers can prioritize traffic by device simply by knowing its IP address. Or by application simply by, well, differentiating between different apps you use.

But how does it know how to differentiate by service? Which is, in fact, one of the most common ways to set up QoS, even in business environments.

Various types of traffic, like torrents, downloads, or calls, travel through the internet using different identification tags called “ports”. 

For example, FTP (file transfer protocol) utilizes ports 20 and 21 to travel. E-mail usually uses port 25, and Internet browsing travels through ports 80 and 443.

In this case, your router doesn’t really know exactly what you are doing. It will just prioritize traffic from one port over the others.

Other Considerations

QoS will look different for everyone. 

Priorities, applications, and devices vary from person to person. But here are a few other things to take into account if you are thinking about implementing QoS in your home router:

  • As we learned above, there are different types of QoS. Not only do they prioritize different things (devices vs. applications for example), they also do it in different ways.

    With QoS by device, you usually set up a speed limit and your router will throttle this device when it exceeds its assigned bandwidth. This option, while helpful, might throttle some of your devices even when it doesn’t really need to.

    QoS by application is managed a bit differently. In this case, your router will assign the maximum possible bandwidth to the prioritized app. How much it assigns will vary by the application’s needs. This is known as adaptive or advanced QoS, because your router intelligently decides how much bandwidth to assign at any given moment. This helps ensure you are always taking advantage of your full bandwidth.
  • This one might be obvious: your router needs to support QoS. While most modern routers, even budget ones, have some type of QoS features, it’s not always the case. There are plenty of high-end routers without any kind of QoS.
  • If an application needs more bandwidth than your ISP provides, QoS will not help. If your bandwidth is 15 Mbps, and an application needs 25 Mbps to function correctly, no amount of QoS will improve the experience. You simply don’t have enough bandwidth.
  • If your latency is too high, QoS will be of little help.
  • Not only routers are capable of QoS. In enterprise environments, you are more likely to see QoS applied at the firewall or switch level for improved performance.
  • Setting up QoS by service is not always perfect. As we learned, your router prioritizes traffic based on the port. If unwanted traffic is using one of the prioritized ports for some reason, your router won’t know the difference and will let it pass first.

Wrap Up

QoS is a double-edged sword. It might significantly improve your experience or make it three times worse.

You will need to be clear about your particular situation to know the best way to implement QoS. 

For some people, QoS by device is of the utmost importance. While for others, streaming video might be crucial no matter what device they are using. 

If you are not sure if bandwidth is your issue, here are some examples of how much different services use

And if you are convinced that QoS is the solution to your problems, you’ll need to access your router’s menu to set it up. Here’s a guide on how to do that.

Was this post helpful?

Leave a Comment