(Help) Bufferbloat/Increase of latency on Wifi

[Yeti]

Bufferbloat tested with DSLreports,fast.com and Waveform to ensure it isn't a site problem
Setup is cake and manual speeds set at 95%
Wireless bufferbloat under load increase of 11-25ms
LAN bufferbloat under load increase of 0-2ms

I know wireless isn't the most reliable and stable testing method but I noticed that after the latest updates (running the latest stable release) it doesn't seem to control bufferbloat/set speeds as well as before over wifi. I would set the speeds at 275/275 but once I use Wifi it would ignore those values and fluctuate between 280-290Mbps.

I also noticed an average increase of 4ms over Wifi that wasn't present before.

Any ideas what could be wrong? Did I do something wrong that could have caused the problem?

Any help much appreciated

 

[thiggins]

4 ms is nothing when you consider Wi-Fi latency variation and variation due to everthing that can happen after the packet leaves your LAN.

 

[Yeti]

4 ms is nothing when you consider Wi-Fi latency variation and variation due to everthing that can happen after the packet leaves your LAN.

I was just curious why it increased all of a sudden. I however want to resolve the WiFi Bufferbloat issue or at least try and determine why it's happening.

 

[thiggins]

Trying to chase down the source of 4 ms of latency on an internet connection will be a frustrating exercise. There are too many possible sources, many of them not in your control or reliably measurable.

 

[Yeti]

The range from the router for both tests is 1 meter

Wireless:

Wired:

Cake settings for an average speed of 290/290

 

[Yeti]

@thiggins Hope the pictures give you a better understanding of what the issue is.

 

[askan7]

It's normal to have higher wifi latency when the link is saturated. Cake Qos doesn't do anything to wireless bufferbloat. Anyway, you shouldn't be saturating the link that close to the router assuming you're using a good AC client and 5Ghz band.

When I was testing Wifi on the ac86u I found enabling Multi-User MIMO helped to reduce latency when the link was saturated. Disabling IGMP Snooping slightly lowered overall latency, even idle.
You'll also want to set a fixed channel, don't want the router to randomly change channels, while you're using the wifi, that can cause large latency spikes.
I'd also make sure any packet aggregation bs is off client side.

 

[L&LD]

@Yeti, you're testing way too close to the router.

Try at realistic distances (minimum 3 to 4 metres, depending on router model).

 

[Tech9]

Any ideas what could be wrong?

Nothing is wrong and there is nothing to fix. Wi-Fi spectrum is shared. You need a RF chamber to measure latency accurately.

 

[Yeti]

The router is an AX88U and I used a desktop PC, Laptop, and iPhone 12 all with the same results over Wifi

I followed @L&LD advice and moved a few meters away from the router and it didn't change the result
I also followed @askan7 advice and disabled IGMP snooping. It didn't make a difference.
I get around 290/290Mbps on tests so I limited my speed to 200/200 and it still didn't make a difference

Ran a Wifi Analyzer and used fixed channels to rule out congestion-made no difference

LAN limits perfectly fine with a max increase of 3ms under load while WiFi increased by 25ms. I think its a Wifi driver issue or something not communicating correctly over WiFi

 

[heysoundude]

does the model you're using not have WiFi Radar, @Yeti ?
that's the router itself reporting what it sees from where it sits - a wifi analyzer on any other device may help you tweak the router, but you need the router to measure its competition to get the settings closer to optimal before you can proceed with a device to optimise the wireless link