RT-AC86U DFS and channel change

[abax2000]

latest firmware 3.0.0.4.384_81049
windows 10 1903, 18362.418
wifi adapter Asus usb-ac68 (same driver long now)

Symptoms:

1. when DFS decides to change channel, there is a noticeable gap in connectivity. This was not the case in the past (any connectivity latency was imperceptible).
2. when changing channel in webui (5GHz band), re-connection of the laptop takes long, and in many cases needs manual intervention. Also this was not the case in the past.

Not sure if it is the firmware, or any w10 update.

Are there similar findings from other users?

 

[ColinTaylor]

How long is the "gap"? If the router changes to another DFS channel it must wait at least 60 seconds before transmitting to ensure the channel is free. If it changes to a non-DFS channel it does not need to wait.

 

[abax2000]

Change is always to a non-DFS channel (typically 36-40, or 38 when using 40MHz bandwidth). Still the gap is there (1-2 sec).
The choice of non-DFS channel was always like this (with all previous firmware version also). But, again, is only now that the gap is obvious.

 

[L&LD]

After you flashed the latest firmware you indicate above, did you do a full reset to factory defaults and then minimally and manually configured the router without using any saved backup config file?

Did you try using a new SSID to see if the old microcode is possibly interfering with the new firmware?

Has the local, (external) WiFi environment changed?

Does flashing back to the previous firmware fix the latency issue?

There can be many reasons you see a difference in addition to the ones you suggested. You will need to methodically eliminate these possibilities one by one to possibly find the root cause.

 

[abax2000]

After you flashed the latest firmware you indicate above, did you do a full reset to factory defaults and then minimally and manually configured the router without using any saved backup config file?
Affirmative

Did you try using a new SSID to see if the old microcode is possibly interfering with the new firmware?
No

Has the local, (external) WiFi environment changed?
Not visibly

Does flashing back to the previous firmware fix the latency issue?
Not tested

There can be many reasons you see a difference in addition to the ones you suggested. You will need to methodically eliminate these possibilities one by one to possibly find the root cause.
Point taken. Just trying to see if other people have the same findings, before starting the witch hunt.

 

[ColinTaylor]

Do you have another 5GHz client that you can test it with? My natural inclination would be to suspect Windows.

 

[AndreiV]

wifi adapter Asus usb-ac68 (same driver long now)

Win10 favourite problem, you'll probably find things get better with new drivers from Windows Update.

 

[abax2000]

Do you have another 5GHz client that you can test it with? My natural inclination would be to suspect Windows.

Oh, you are so biased
Only available alternative is android smartphones, but I cannot really spend my time surfing and what not on a smartphone waiting to see what happens
On a first look, when changing channels on webui, android clients are much faster in seeing the new 5GHz network and reconnecting than w10.

 

[abax2000]

Win10 favourite problem, you'll probably find things get better with new drivers from Windows Update.

Drivers installed are old, but also the latest available on Asus site.
Can windows update provide something different?

 

[L&LD]

Drivers installed are old, but also the latest available on Asus site.
Can windows update provide something different?

Possibly, depending on your computer model, age of the device and the specific WiFi module installed.

I've never seen 'better' with older drivers or firmware. I would always keep the system as up-to-date as possible. Even if they have a few teething issues that take a few days to resolve.

 

[AndreiV]

Can windows update provide something different?

Try it and see what happens. Win 10 always tries to run devices like USB dongles on Windows own drivers.

I have some Wireless AC dongles and the official drivers are totally useless on Win 10, always dropping out or failing to load at boot. Remove the provided software , plug in dongle and Windows finds suitable drivers and they work perfectly.

 

[abax2000]

Tried several things, trying to follow some suggestions above.

1. Reverted to firmware 45717. No change.
2. Rechecked the drivers for AC68, and saw that driver is indeed "new" (date 11/7/2019, v.1030.25); I have just forgotten the update.
3. Disabled AC68, and reverted to the build-in Intel9560. This seems to improve things (no noticeable lag when DFS kicks in).

So now, I have to retest the older AC68 Asus driver, or the windows inbox ones.

As for the RT AC86U:

1. Cannot be sure, but suspect that it gives too many false-positives. A neighbouring D-Link uses same channels, but I never see it change frequencies.
   1. Following issues have been shared with Asus support (a year or more ago), but never came to fruition:
2. DFS-driven changes are not fully recorded in routers logs (perhaps in General Log, with timestamps), in order to facilitate troubleshooting.
3. When DFS is activated, router is moved to a non-DFS frequency; but it does not revert back following the non-occupancy period. Asus says that the router waits to first see no stations connected, and then move back. As some appliances/devices will be always-on, this practically means that everytime you need a reboot (pita).
4. It would be much more convenient to introduce some relevant settings, so the user can choose this behaviour.
5. It would be also helpful to have off-channel CAC implemented, so not-affected DFS channels can be readily available for hoping.

 

[Val D.]

I've never seen 'better' with older drivers or firmware.

Seriously? ASUS last two firmware updates, as recent example.
Do you work in IT? Remember when Microsoft updated a keyboard driver and boot-looped thousands of HP desktops? No?

 

[L&LD]

Seriously? ASUS last two firmware updates, as recent example.
Do you work in IT? Remember when Microsoft updated a keyboard driver and boot-looped thousands of HP desktops? No?

I never said to update to a problematic version.

Newer doesn't mean bleeding edge.

 

[Val D.]

I never said to update to a problematic version.

Older was actuality better, correct? Many examples, especially in PC software. This is why Windows has “revert to previous version” option in Driver Update tab. Never seen newer driver causing issues? How do you know the newer version is problematic before installing it? I know what you are going to answer, but 99% of users don’t search Google before clicking on the Update button.

 

[L&LD]

Older was actuality better, correct? Many examples, especially in PC software. This is why Windows has “revert to previous version” option in Driver Update tab. Never seen newer driver causing issues? How do you know the newer version is problematic before installing it? I know what you are going to answer, but 99% of users don’t search Google before clicking on the Update button.

No, the older version was updated because there were issues. Otherwise, no need for an update.

If and when a newer driver causes issues it usually a simple matter to revert to the previous version. Staying on the old one because of being scared of possible bugs is just being paranoid.

 

[Val D.]

Staying on the old one because of being scared of possible bugs is just being paranoid.

Most users are not very tech savvy and if something is working good they don't touch. You've seen this in your practice, I believe. The real problem is when something auto-updates to a non-working version, like it happened few times with Windows 10 updates and users have no control over the update process. The point is in software not always newer is necessarily better. Anyway, this is a different conversation.

BTW, I have no DFS channel options on Asuswrt-Merlin 384.12 version. Is it ASUS stock firmware specific + probably region specific? I don't remember what was available in ASUS stock, honestly.

 

[Grisu]

Merlin wont touch Wifi and its settings, so it must be the same with stock and region cant be changed on 86U except you have a chinese version.

 

[Val D.]

Merlin wont touch Wifi and its settings

I know, but the current Asuswrt is actually newer than the last Asuswrt-Merlin, so I was wondering if ASUS now allows DFS channels for US/CA versions.

 

[RMerlin]

I was wondering if ASUS now allows DFS channels for US/CA versions.

Yes, since the 81049 release.