QoS issues with AC66U

[jcazes]

Hi all,

I'm seeing a bizarre issue where I'm getting half the download speeds I should be getting. I have a 200/20 connection and get 200Mbps down when QoS is off, but 100Mbps when it's on. Would appreciate any and all advice!

Here's my setup:

• Manually assigned IP addresses for laptop and phone
• DHCP configuration that assigns all other devices to IP range 192.168.0.10 to 100
• QoS rules that rate-limit guest range so they max out at 30Mbps down and some time upload rate

Here are screenshots of my config:

This 100mbps wall seems to be there on my phone and my laptop, and it happens regardless of whether those last two lines of QoS rules are in place (that assign my 192.168.1.* devices in the "highest" tier).

Asus support said they've never seen this before, so I'm guessing this is something I might have done incorrectly!

 

[RMerlin]

QoS forces the router to disable HW acceleration, which will limit its max speed to around 125-150 Mbps. With the QoS overhead, this could explain why it's closer to 100 Mbps.

To use QoS at such speeds you will need a more powerful router.

 

[jcazes]

QoS forces the router to disable HW acceleration, which will limit its max speed to around 125-150 Mbps. With the QoS overhead, this could explain why it's closer to 100 Mbps.

To use QoS at such speeds you will need a more powerful router.

Well that's a massive bummer. Thanks for the insight! Could I pull this off with custom firmware like yours?

If not, which router would you recommend to be able to do this?

 

[RMerlin]

Well that's a massive bummer. Thanks for the insight! Could I pull this off with custom firmware like yours?

No, this is simply a power limitation of the router. HW acceleration works by bypassing part of Linux's network stack, which includes the QoS implementation.

If not, which router would you recommend to be able to do this?

An RT-AC56 or RT-AC68 can process around 300 Mbps without HW acceleration, so that would leave you some room for the QoS processing overhead. If you want more room, the RT-AC87 has a new DPI-based QoS engine that's able to work with HW acceleration enabled, giving you 500-700 Mbps of processing capabilities.

Asus also intends to bring that new QoS engine to the RT-AC56 and RT-AC68 sometime before the end of the year, but there's no precise ETA yet.

I can't do it myself at this time because that new engine is based on closed-source components, and the only version available at the moment cannot be used on another device than the RT-AC87, as it expects the Quantenna environment to be present.

 

[Joetech]

I currently see this issue on my RT-N66U as well, going from 150 Mb/s down to 94 Mb/s down.
I'm looking at the RT-AC68U, however, has anyone had some first hand experience with it to know that when QoS is enabled (or HW acceleration off) that it'll easily provide that sort of internet speed?

Thank you!!

 

[L&LD]

RMerlin has already confirmed around 300Mbps with both the RT-AC56U and the RT-AC68U not to mention the possible DPI engine that will enhance that even higher, as promised by Asus.