Airtime Fairness question

doczenith1

Very Senior Member
I noticed that in a situation where airtime fairness should help it actually makes things worse. With airtime fairness on, when I copy a large file from the USB drive attached to RT-AX56U to my laptop that has Wi-Fi 4 and 2 streams (we can consider this laptop a slow client) and, at the same time, play a video (via DLNA) from that drive on my TV (Wi-Fi 5, 2 streams), the video stutters every two seconds. At this time, the copy speed remains stable. When I run a speed test on my TV during the copy operation, I get about 20Mbits. My understanding is that with airtime fairness the file copy speed should be reduced to give more airtime to the TV, but it does not happen.

Turning airtime fairness off solves the problem: the video plays normally, and, during the playback, the file copy speed is reduced a bit. Moreover, the same speed test on the TV shows speeds that are on average 15 Mbits higher. I don't know whether it applies to other router models, but looks like Broadcom's driver copes with multiple clients better without the airtime fairness setting enabled.

I'm old school. Is WiFi 4 ac or n? I think where airtime fairness helps the most is with really old/slow clients still on g.
 

leerees

Senior Member
If you run a public network you may consider enabling it, but only if you knew you had old b/g cclients.. it's a very specific use case and on a home network it's just going to cause problems due to compatibility issues. It would be better to retire the offending b/g clients. If you run a public network, simply disallow b/g clients and you won't need airtime fairness anyway.
 

FTC

Senior Member
Hi, just to add my experience to this thread, I have been running fine with airtime fairness OFF for several years but occassionally found some difficulties to connect devices to the network. This afternoon I could see that my PC was refusing to connect to the near router (RT-AX88) at 5Ghz band and connected badly to the faraway node (RT-AX56). Then I discovered it was due to most of the bandwith to the '88 was being used by a high speed transfer in 'n' mode from another client. I turned ON airtime fairness for the 5Ghz band and 'voilá' the clients could connect and work again with the '88. So I'll leave this setting for a few days and see if any negative effect is seen.
 

netmik3

Senior Member
Hi, just to add my experience to this thread, I have been running fine with airtime fairness OFF for several years but occassionally found some difficulties to connect devices to the network. This afternoon I could see that my PC was refusing to connect to the near router (RT-AX88) at 5Ghz band and connected badly to the faraway node (RT-AX56). Then I discovered it was due to most of the bandwith to the '88 was being used by a high speed transfer in 'n' mode from another client. I turned ON airtime fairness for the 5Ghz band and 'voilá' the clients could connect and work again with the '88. So I'll leave this setting for a few days and see if any negative effect is seen.

My printer doesn't stay connected with it on.
 

netmik3

Senior Member
Thanks for the input. With what firmware level and router does this happen ?

I use the latest Merlin on AC5300. It's an HP Envy 5660. I actually don't know if it would still do it. But it happened for years so I just keep it off.
 

charlesbuzz

New Around Here
For me, disabling Airtime Fairness solved a lot of drop connection problems for devices like Wemo light switch or wired chromecast that show almost
instantly in Youtube app on iphone.

But it cause slow internet access on iPhone or iPad, speedtest drop from 50 mbs to 15mbps

Router: RT-AC86U
version: 3.0.0.4.386_41634
 

Similar threads

Latest threads

Sign Up For SNBForums Daily Digest

Get an update of what's new every day delivered to your mailbox. Sign up here!
Top