ASUS RT-AC68U limitting bandwidth maximum 200 Mb/s

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palula

New Around Here
Hi everyone.

I have an RT-AC68U and recently upgraded my ISP plan to 400 Mb/s, however my ASUS Router comprising of the latest Merlin firmware (384_19) will not achieve speeds over 200 Mb.

Weirdly, my upload speeds have increased from 75 Mb/s to ~156.66 Mb/s as of immediately after buying the new upgrade plan. On the other hand the download speed, which prior to the upgrade was 200 Mb/s and as of now corresponds to 400 Mb/s, is achieving values around ~180.67.

I have configured my computer to perform the PPPoE dialing procedure and am able to achieve speeds close to, and even higher than 400 Mb/s when dialing directly on my eth0 interface (bypassing the router).

Is there anything that has to be done for the ASUS RT-AC68U router to specifically acknowledge speeds over 200 Mb/s?

Thank you.
 

ColinTaylor

Part of the Furniture
Go to Tools > System Information > HW acceleration. If it is disabled (e.g. because QoS is active) that will be the reason.
 

palula

New Around Here
I believe this feature isn't available at my firmware because I'm using Merlin (384.19). However, after a lot of troubleshooting I found what was producing the problem.

At home I've configured a guest network on the first 2.4 Ghz slot available (the only guest network I've configured, since the router allows up to 6 guest networks). Additionally, I added some downspeed/upspeed QoS as a means to determine the maximum download/upload speeds for the guests (e.g: 15Mb/s). Whenever I did that, the speed of the WAN interface automatically dropped to a maximum velocity of 200 Mb/s.

I know this because I restored all the configurations to factory defaults and it started to work in the correct speed (~400 Mb/s). After that, I started to tweak my configuration step-by-step and after each tweak I checked the speed of the router.

As soon as I got to the Guest Network (GN) config, the speed dropped. Immediately after that, I tested the speed and still 200Mb/s. Soon afterwards, I found out that whenever you establish QoS for theGN, an automatic configuration spawns within the Adaptive QoS > Enable QoS section. So in order to resolve this I had to disable QoS, and reboot the router (never forget to reboot).

Now everything is working at the expected speed for the WAN connection, however I don't have a clue as to why activating the GN would limit my WAN connection to 200Mb/s rates.

Hope this helps anybody in the process of encountering the same error with their routers.
 

ColinTaylor

Part of the Furniture
I believe this feature isn't available at my firmware because I'm using Merlin (384.19).
That feature is something that Merlin added to his firmware that isn't present in stock.

As I said, enabling certain types of QoS will cause your problem and the Tools page should have indicated this as the cause.
 

Adooni

New Around Here
you should be OK with adaptive QoS and fq_codel (I am using WAN packet overhead as 4 (Ethernet) - this still allow to set LAN - switch control - auto ( CTF (Cut Through Forwarding) is enabled. ). FA (Flow Accelerator) is not supported by this router therefore you will not loos anything. you will need reboot router to get it setup
 

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