RT AC88u slow wifi - but only when routing to internet

[Ikaros69]

This issue has been boggling me for the past weeks, since I got fiber connection.
I am quite experienced with computer and network infrastructure (it's within my profession), but this I cannot solve. Here goes:

My service is 250/100 mbps.
My setup is:
Asus rt ac88u, connected to the fiber converter on WAN, and to a managed switch on Lan 1.
On the managed switch I have 2 pcs, and another switch connecting TV, xbox, ATV etc.
I get 250/100 mbps, wired, using speedtest.net and various other online speedtest.
I get 80-100/100 mbps, wifi, using speedtest.net and various other online speedtest.
I get 866,7/866,7 mbps, wifi, locally between wirless devices and PC/ATV.
I get 866,7 TX and RX when looking in the routers interface listing devices and their connection speed.
I get 700-800 mbps using test tools that check wifi signal strength.

This has made me exclude any problems with wifi signal, channel distruptions etc (since I've tested it enough).

I've tested various firmwares (including merlin) on the router.
I've tested various wifi settings on the router.
I've tested another router (Asus rt ac68u) connected to the fiber converter
I've tested another router (Asus rt ac68u) connected to the LAN
I've tested wifi tethering on a pc.
I've tested with disconnecting everthing, just having the router connected to the WAN.
I've tested in another room in my house (to eliminate signal interference)
All gave the same result: 80-100/100 mbps.
I've tested modifying the MTU on the router interfaces (ssh -> ifconfig)


I've been in contact with Asus support, whom agreed with me that my troubleshooting is enough to prove there's nothing in the router.

Next thing that boggles me totally: I took my router to my neighbour, attached it (he has 250/100, but another ISP). There we got 250/100 wifi. Same config, same router, same test device (in this case an iphone X and his various android phones).

I spoke to my ISP, trying to get them to explain how they used TCP congestion, if that could be the issue. But their support wasn't the brightest, and couldn't help me.

So pretty please, give me some idéas, what to do next? Or perhaps, what is the problem?

Regards

 

[emsik]

...

My service is 250/100 mbps.
My setup is:
Asus rt ac88u, connected to the fiber converter on WAN, and to a managed switch on Lan 1.
On the managed switch I have 2 pcs, and another switch connecting TV, xbox, ATV etc.
I get 250/100 mbps, wired, using speedtest.net and various other online speedtest.
I get 80-100/100 mbps, wifi, using speedtest.net and various other online speedtest.

I've got similar problem with ac86u https://www.snbforums.com/threads/poor-download-speed-over-wifi-with-asus-ac86u-5-ghz.54639/ but also doesn't find the solution. Please give me a sign when you find any

 

[Ikaros69]

My investigation pointed to my ISPs TCP-handling, mainly their tcp congestion control and utterly stupid network infrastructure.
So I changed ISP, and now My Wifi max out as well (250/100).

 

[emsik]

My investigation pointed to my ISPs TCP-handling, mainly their tcp congestion control and utterly stupid network infrastructure.
So I changed ISP, and now My Wifi max out as well (250/100).

I'm not a network guy but if your wired connection on the same router doesn't has any congestion control problems why your wireless connection does?

 

[Ikaros69]

It was a hint I got from a friend, that my Wi-Fi probably generated more tcp packages. And the messy infrastructure and tcp congestion my isp has was more noticeably there.

I tested it by setting up wireshark, and noticed that it was true - my Wi-Fi generates a lot more tcp packages compared to my wired.

Have you done local tests?
That is the best way to exclude problems on your end. File transfer locally etc. I also used a network speed tester application on my iPhone and a server application on my Apple TV. That verified my 866mbps local Wi-Fi.

 

[emsik]

Have you done local tests?
That is the best way to exclude problems on your end. File transfer locally etc. I also used a network speed tester application on my iPhone and a server application on my Apple TV. That verified my 866mbps local Wi-Fi.

Thanks for response
Right now, i've made test with recommended on forum iperf settings (https://www.snbforums.com/threads/p...wifi-with-asus-ac86u-5-ghz.54639/#post-461605) does it looks like a problem with router?