Level 2 hardware acceleration with new firmware (2021)

Corey Vidal

Occasional Visitor
Hi.
I know a big firmware leap went out at the beginning of this year (2021) that changed a lot of things. I'm having trouble finding information on Flow Acceleration with the newer firmware. I'm running an RT-AC88U as my main router, and an RT-AC1900P (which is basically an RT-AC68U) as a mesh node.

I've upgraded to gigabit internet, and want to get as much hardware acceleration as possible. I know in the past, you could see if your hw acceleration was Level 1 or Level 2 by going to LAN > Switch Control and reading what is written in yellow to the right of the NAT Acceleration dropdown. I have this written in old notes of mine, that applied in past years:

To the right in yellow text, it will say 1 of 3 things:
  1. NAT traffic is processed by CPU.
  2. CTF (Cut Through Forwarding) is enabled. (Level 1)
  3. CTF (Cut Through Forwarding) and FA (Flow Acceleration) accelerator are enabled. (Level 2)


I'm running the latest stable firmware (386.2_6) on both my routers. Here are all the things that I've done:
  • Uninstalled FlexQoS
  • reboot
  • Adaptive QoS > QoS > Toggle "Enable QoS" to OFF
  • reboot
  • Traffic Analyzer > Statistic: toggle "OFF"
  • reboot
  • Administration > Privacy: Withdraw consent
  • reboot
No matter what, if I go to LAN > Switch Control I'm still only seeing CTF (Cut Through Forwarding) is enabled.

I ssh'ed into the router and tried this:

runner enable
and
fc enable

Terminal returns:
-sh: runner: not found
and
-sh: fc: not found

Not sure if these are supposed to work or not. I found them in old threads on this forum.

I have successfully ran:
nvram set runner_disable=0
nvram commit
reboot

and
nvram set fc_disable=0
nvram commit
reboot

After running those two, if I try

nvram get runner_disable
or
nvram get fc_disable
I get:
0

Which is good! (I think.)
But having done all of this, if I go to LAN > Switch Control I'm still just seeing CTF (Cut Through Forwarding) is enabled.
FC is the new CTF, right? So, FC is enabled. Good.

What about "Runner"? Runner is the new "Hardware Flow Accelerator" right? How do I see about that?

How do I confirm if I'm running Level 2?

(I tried to write thoroughly, in case this helps anyone in the future searching the forums.)
 

ColinTaylor

Part of the Furniture
Runner and Flow Cache are hardware features of the newer model routers. You cannot enable them on your routers because they don't have it.
 
Last edited:

dave14305

Part of the Furniture
Doesn’t the Tools / Sysinfo page show the level and reasons either is disabled?
Code:
nvram show | grep ^ctf
 

RMerlin

Asuswrt-Merlin dev
Doesn’t the Tools / Sysinfo page show the level and reasons either is disabled?
Code:
nvram show | grep ^ctf
It partly does. The line between what is compatible and what isn`t is kinda muddy with HND, so I can no longer provided an accurate reason as to why certain hardware acceleration layers are disabled on the HND platform.

But it will accurately report which acceleration levels are enabled, by directly querying the hardware (rather than just checking the nvram state as it used to do, which might not always be 100% accurate).
 

Corey Vidal

Occasional Visitor
On Tools > Sysinfo, I only see:

HW acceleration Enabled

Which is REALLY confusing. I spent 3 hours Googling the forums and it seems everyone sees stuff here that I don't see?

2021-07-12_165543(440)_chrome_1571×2160_EREBUS.png


Is it correct that I shouldn't see any details for HW acceleration? It's all been quite confusing, especially when searching the forum.
 

Corey Vidal

Occasional Visitor
Doesn’t the Tools / Sysinfo page show the level and reasons either is disabled?
Code:
nvram show | grep ^ctf

When I ran that, I got this:

Code:
ctf_disable=0
size: 75296 bytes (55776 left)
ctf_disable_force=0
ctf_nonat_force=0
ctf_pt_udp=0
 

Tech9

Part of the Furniture
What speeds are you getting wired to the router? If around 900Mbps, there is nothing to accelerate more.
 

dave14305

Part of the Furniture
When I ran that, I got this:

Code:
ctf_disable=0
size: 75296 bytes (55776 left)
ctf_disable_force=0
ctf_nonat_force=0
ctf_pt_udp=0
The absence of the ctf_fa_mode variable prevents the GUI from knowing what’s what. I just don’t know if that variable is supposed to be there on an AC88U.
 

Corey Vidal

Occasional Visitor
The absence of the ctf_fa_mode variable prevents the GUI from knowing what’s what. I just don’t know if that variable is supposed to be there on an AC88U.

Well, I used to be able to get to Level 2 before the new 2021 firmware. Maybe I could try setting it manually?
Googling seems to show "0" and "2" as being options?
 

ColinTaylor

Part of the Furniture
Well, I used to be able to get to Level 2 before the new 2021 firmware. Maybe I could try setting it manually?
Googling seems to show "0" and "2" as being options?
Some models incorrectly showed two different levels in the past. You're trying to fix a problem that doesn't exist.
 

Corey Vidal

Occasional Visitor
Some models incorrectly showed two different levels in the past. You're trying to fix a problem that doesn't exist.

I see. So instead of it being:
  • I used to be able to get to Level 2, CTF+FA, and now I can't, and I'm trying to
It's:
  • When I got to Level 2, CTF+FA in the past, it wasn't actually true. The new 2021 firmware now reports accurately the fact that I can never get there.

Yeah? Something like that?
 

ColinTaylor

Part of the Furniture
I see. So instead of it being:
  • I used to be able to get to Level 2, CTF+FA, and now I can't, and I'm trying to
It's:
  • When I got to Level 2, CTF+FA in the past, it wasn't actually true. The new 2021 firmware now reports accurately the fact that I can never get there.

Yeah? Something like that?
That certainly appears to be the case with the RT-AC68U based on numerous posts and previous comments by RMerlin. I don't remember anybody raising this as an issue (one way or the other) with the RT-AC88U (but it sounds likely exactly the same problem unless your notes are for the wrong router).
 

Tech9

Part of the Furniture
Something like that?

This is not the only non-working feature in AC88U. If your router was manufactured with early BCM4366 B1 radios, you also have advertised, but non-functional MU-MIMO. Just use the router the same way as before. It will work with your new ISP just fine.
 
Last edited:

Corey Vidal

Occasional Visitor
This is not the only non-working feature in AC88U. If your router was manufactured with early BCM4366 B1 radios, you also have advertised, but non-functional MU-MIMO. Just use the router the same way as before. It will work with your new ISP just fine.
Oh, wonderful. I used to be so proud of owning this router, haha. 5 years have gone by fast.
 

ColinTaylor

Part of the Furniture

SomeWhereOverTheRainBow

Part of the Furniture
Looking at the history of that file it has never been enabled. So the OP's notes were wrong (for the RT-AC88U).
You are correct, but could there have been a time the GUI was wrongly reporting something for that model, that never existed. Especially if it was something read off of nvram variable states?
 

ColinTaylor

Part of the Furniture
You are correct, but could there have been a time the GUI was wrongly reporting something for that model, that never existed. Especially if it was something read off of nvram variable states?
Without have a time machine it's impossible to know for sure, but it seems highly unlikely.
 

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