How Your WiFi Band Impacts Low Latency Connections

By PJ Palomaki

Our home network is one of those things we often take for granted. We can see our broadband as just another utility in the household, which feeds our myriad of devices with data from all over the globe. It enables us to watch TV series on our Smart TV’s and browse social media on our mobile devices. We can even turn down our thermostat for holiday, from our smart watch, while boarding the plane. We hardly ever need to interact with the device that brings this internet access to our household, the router, and most of the time our only reminder of its existence are those blinking lights. That, and the odd occasion when suddenly, out of nowhere, our WiFi network goes down and we reach to the back of the box, sitting in the far corner of the living room and turn it off and on again, kicking it back to life and restoring peace and normality to the household. That was, until we got that new router with two WiFi access points, 2.4 Ghz and 5 Ghz, and we were left questioning which one should we use…

2.4 Ghz Vs 5 Ghz Wifi

We feel so at home with our trusty 2.4 Ghz network that we might feel suspicious that there’s a new player on the field; 5 Ghz, especially as it promises shorter signal range! Why would we want to switch to something that affects us adversely? Well, WiFi signal range is only one aspect we should be considering, especially as we’re moving more towards network and internet services which significantly benefit from not only speedy, but low-latency connections.

The problem with the frequency range that 2.4 Ghz occupies is that in today’s device-heavy society, many other radio devices compete in the same range, including microwaves, cordless phones, baby monitors and garage door openers, which clutter the signal and effectively create gridlocks in the airwaves, slowing down how quickly information gets from A to B. On top of that, if you attempt to join your home WiFi network on any of your devices, most likely you’ll see many other 2.4 Ghz networks too, your neighbors for instance, which again fights for that same frequency range.

By contrast, the curse of 5 Ghz is also its blessing; shorter ranges mean less clutter from other 5 Ghz networks nearby as they won’t reach your household. 5 Ghz’s higher frequencies also means that all those baby monitors won’t interfere with your 5 Ghz network, so even less traffic. But why should we be concerned with how quickly information gets from our router to our devices? After all our media streaming services have been working fine until now.

Consistent Low-Latency, Better Than High Speed

The problem with our fixation with the speed of our network is that we’ve neglected what’s becoming just as, if not more, of an important factor, and that is the quality of our network. With network services like media streaming, the delay between queries from these apps and the response from servers has negligible impact on the quality of the experience. We don’t perceive the 60ms delay between tapping the play button and the video starting as there is far greater delay in the service backend anyway. And as these services can buffer video and other content ahead of when it needs to be presented to the viewer, variation between queries has no perceivable affect on the user. The quality of the network can be very poor and these services can deal with that, due to the asynchronous nature of the traffic required.

The WiFi Game Changes With Game Streaming

But when we start dealing with services, like game streaming, where you can’t buffer frames ahead of time, (as action is interactive, not just a pre-defined stream of video) every millisecond introduced into the network can have a huge impact on responsiveness and thus the quality of the experience. Imagine every time you press a controller button there is a 100ms delay in action showing on-screen. In a multiplayer FPS, that 100ms will get you killed. It will make your game streaming seem laggy and any game requiring quick player reactions becomes unplayable. But the actual delay between queries is only half of the problem. The second part is called delay variation, or jitter, which measures how much the delay in the signal changes between queries. You may be able get low latency reading with 2.4 Ghz, but due to the traffic in the frequency range used by 2.4 Ghz, you’re very unlikely to get consistent low latency. Consistent low latency is crucial for services like game streaming. The way video encoding and frame delivery works on these services is that they must be able to predict how fast the network is and what the expected latency is between packets. If there’s a big deviation in the delay it’s like having a racing car on a congested motorway; every time the car in front of you hits the brakes, your momentum is lost and you have to start from near-standstill. Unfortunately, there is no real way of taking over other traffic, you just have to wait in line.

The Ping Test

So what’s the actual difference between 2.4 Ghz and 5 Ghz networks in terms of quality? Let’s look at some hard numbers with a simple example. In the following test I used my laptop to ping my home router using three networking methods; 2.4 Ghz, 5 Ghz and Wired, using a LAN cable. A ping test isn’t used to measure the speed of the connection between devices, but rather the delay between the two and the variation of these queries. I shut down as many other applications as I could that use my network, as they might distort my results, and ran 100 ping queries with each connection, keeping the laptop in the same place between sets. Here are the results:

Wired numbers: min/avg/max/stddev = 0.322/0.541/0.665/0.094 ms. 5G numbers: min/avg/max/stddev = 1.186/4.609/8.487/0.966 ms. 2.4 Ghz numbers: min/avg/max/stddev = 1.932/12.908/52.666/10.398 ms

As you can see, there is a significant difference in the delay variation between 2.4 Ghz and 5 Ghz. Putting it bluntly, what the ‘stddev’ or standard deviation shows in the numbers under the graph is that 5 Ghz’s connection is over 10 times more consistent than 2.4 Ghz, in my testing environment. 2G doesn’t benefit much from the fairly decent Nighthawk X6 router as I have no less than seven other 2.4 Ghz networks appearing in my networks list (and only one 5 Ghz besides my own). It’s fair to point out that the wired connection beats wireless connections hands down both in variation and overall latency, which is to be expected, and because of that, it is often encouraged to be used over WiFi for very latency-sensitive network services.

Go for 5 Ghz

So what’s our suggestion based on all this information? 2.4 Ghz has been serving us fine for most asynchronous network services, like box-standard media streaming or social media use, but if you want to use wireless networking for latency-sensitive services, such as game streaming, stay well away from 2.4 Ghz! The traffic in the frequency range that 2.4 Ghz occupies is like a gridlocked highway full of starts and stops which makes it impossible to establish reliable, responsive streaming. You’ll just end up frustrated from the experience and likely ditch the service without considering it fully. Always use at least 5Ghz WiFi and if you have a choice, opt for wired connection for your most critical network services.

Always Go With Wired If You Can

As the graphic shows, wired is always best. WiFi adds latency and can lead to dropped frames due to jitter. That’s not saying wired will be perfect, but it will improve the quality of your streaming. Have fun!

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