ASUS ZenWiFi AX (XT8), suddenly slow 5GHz Backhaul transmit speeds on all nodes.

comlab

New Around Here
Hi all
I have 4 ZenWifi AX XT8 devices in a mesh configuration, one as Router and 3 as nodes. I bought the sets on November last year, all was working okay for 1-2 month. However, since a few days I have very serious problem. After a few hours my 5GHz Backhaul Transmit speed on all nodes drop to ~100 Mbps, and this on all 3 nodes at the same time. Once I reboot all devices the speeds are perfect again, however a few hours later I experience exactly the same problem again. Currently I’m on the latest firmware (3.0.0.4.386_46061), however I had the issue with the previous version as well. Any idea what I can do? So far, I have not factory reset all the devices, is it worth to do so, or is there something else I can do?

Suddenly slow Backhaul Transmit rates on all nodes after a few hours:
1642936506761.png


Once I reboot all the devices the speeds are fine for a few hours, then they drop back again to ~100 Mbps
1642936533834.png
 

L&LD

Part of the Furniture
Do the factory reset. It will save you hours of wild goose chasing.

At the very least, it will give you a solid foundation to do real troubleshooting from.

Do a minimal and manual configuration after you've fully reset the router. Do not use a saved backup config file. Do not 'blindly' use old scripts and settings/options that worked 'once upon a time'.

[Wireless] ASUS router Hard Factory Reset | Official Support | ASUS Global

Note that you may need to do the above more than once for the router to become stable. If it is stubborn, I would reset it via the WPS Button method (above), the Reset button method, and via the GUI. And repeat all three if the issues persist.

Do this to all the routers/nodes. Test a different node as the main router too, if all else fails.

Be sure the main router is fully functional (including after a reboot) before adding fully reset nodes (do not try to configure the nodes via their GUI, only use the main router's GUI to add fully reset nodes as per the link above).
 

tgl

Regular Contributor
A few more thoughts beyond L&LD's excellent advice:

* There are a lot of reports on these forums that people don't find any XT8 firmware releases after 42095 to be stable. YMMV for sure, but don't assume that latest firmware = best firmware. If you do try another firmware version, definitely do a hard reset and reconfigure as L&LD describes. Transferring config between versions seems not to work as well as it ought.

* If you can, set up the ASUS routers to send their logs to an rsyslog daemon (see Remote Log Server in the System Log tab). This isn't terribly hard if you have a Linux machine at hand. You can see the last day or two's worth of log data in the System Log tab, but when you are trying to trace problems, a longer-lived view of that data is invaluable.

* If you live within ~50 miles of an airport or weather radar station, you may need to prevent the ASUS nodes from using "DFS" channels for backhaul. I had that problem, and the symptoms were a bit different from what you describe, but it was similar in that it worked for a few hours and then failed hard. Look for mentions of "radar detected" or "radar timeout" in the System Log data; if you see that near the times of problem onset, you've identified your issue.
 

Gustour

Occasional Visitor
aren't those number "live" rate ? I mean if nothing is using your network il will close to 0, and if you are streaming, downloadinf etc, then you ll see a number in function of what you are doing.
 

shama_001

Occasional Visitor
Not exactly the same title (PHY) in wired backhaul but indeed by my setup these numbers are dynamic
Whatever the numbers make an iperf3 test and you'll know the exact bandwidth on each node
 

comlab

New Around Here
First, thanks to you all for replying, much appreciated!
@Gustour, if the PHY rate is going down to ~100 Mbps then the transmit speed really sucks, believe me ;-) My numbers are dynamic too but if they go down to 100 Mbps you really feel this.
@tgl, thank you very much for your explanation. I live indeed 7miles away from a little airport and I'm surprised that this can have influence on my Wifi! I noted the "[ADTBW]Radar detected, wait for radar timeout" and "[ADTBW]Radar timeout" message in my log. However I can't disable the "Auto select channel including DFS channels" option. Well I can, but if the page is reloading the checkbox is selected again. I'm wondering if I only have DFS channels for the backhaul Wifi available? I also noted that the nodes are not able to connect with 160MHz. If I select 160MHz only they falling back to 2.4Ghz, I'm wondering if this is normal? I found some other discussion here: https://www.snbforums.com/threads/asus-zenwifi-xt8-5ghz-2-band-dfs-channel-backhaul-behavior.66317/

I now switched to 80Mhz and will see if it's stay stable. And yeah I think I have to go through the pain of resetting all devices.


SSID: "backhaul"
noise: -88 dBm Channel: 100/80
BSSID: xx:xx:xx:xx:xx:xx Capability: ESS RRM
Supported Rates: [ 6(b) 9 12(b) 18 24(b) 36 48 54 ]
HE Capable:
Chanspec: 5GHz channel 106 80MHz (0xe06a)
Primary channel: 100
HT Capabilities: 40Mhz SGI20 SGI40
Supported HT MCS : 0-31
Supported VHT MCS:
NSS1 Tx: 0-11 Rx: 0-11
NSS2 Tx: 0-11 Rx: 0-11
NSS3 Tx: 0-11 Rx: 0-11
NSS4 Tx: 0-11 Rx: 0-11
Supported HE MCS:
80 Mhz:
NSS1 Tx: 0-11 Rx: 0-11
NSS2 Tx: 0-11 Rx: 0-11
NSS3 Tx: 0-11 Rx: 0-11
NSS4 Tx: 0-11 Rx: 0-11
160 Mhz:
NSS1 Tx: 0-11 Rx: 0-11
NSS2 Tx: 0-11 Rx: 0-11
NSS3 Tx: 0-11 Rx: 0-11
NSS4 Tx: 0-11 Rx: 0-11

Interference Level: Acceptable
Mode : AP Only

DFS status: state In-Service Monitoring(ISM) time elapsed 14545050ms radar channel cleared by DFS channel 100/80 (0xE06A)

Channel Information
----------------------------------------
Channel 100 A Band, RADAR Sensitive
Channel 104 A Band, RADAR Sensitive
Channel 108 A Band, RADAR Sensitive
Channel 112 A Band, RADAR Sensitive
Channel 116 A Band, RADAR Sensitive, Passive
Channel 120 A Band, RADAR Sensitive, Passive
Channel 124 A Band, RADAR Sensitive, Passive
Channel 128 A Band, RADAR Sensitive, Passive
Channel 132 A Band, RADAR Sensitive, Passive
Channel 136 A Band, RADAR Sensitive, Passive
Channel 140 A Band, RADAR Sensitive, Passive

Stations List
----------------------------------------
idx MAC Associated Authorized RSSI PHY PSM SGI STBC MUBF NSS BW Tx rate Rx rate Connect Time
xx:xx:xx:xx:xx:xx Yes Yes -48dBm ax No Yes Yes Yes 4 80M 1441.2M 1441.2M 04:02:01
xx:xx:xx:xx:xx:xx Yes Yes -65dBm ax No Yes Yes Yes 4 80M 1020.8M 864.7M 04:02:02
xx:xx:xx:xx:xx:xx Yes Yes -44dBm ax No Yes Yes Yes 4 80M 1921.5M 1921.5M 04:02:04
 

KingBravery

Senior Member
First, thanks to you all for replying, much appreciated!
@Gustour, if the PHY rate is going down to ~100 Mbps then the transmit speed really sucks, believe me ;-) My numbers are dynamic too but if they go down to 100 Mbps you really feel this.
@tgl, thank you very much for your explanation. I live indeed 7miles away from a little airport and I'm surprised that this can have influence on my Wifi! I noted the "[ADTBW]Radar detected, wait for radar timeout" and "[ADTBW]Radar timeout" message in my log. However I can't disable the "Auto select channel including DFS channels" option. Well I can, but if the page is reloading the checkbox is selected again. I'm wondering if I only have DFS channels for the backhaul Wifi available? I also noted that the nodes are not able to connect with 160MHz. If I select 160MHz only they falling back to 2.4Ghz, I'm wondering if this is normal? I found some other discussion here: https://www.snbforums.com/threads/asus-zenwifi-xt8-5ghz-2-band-dfs-channel-backhaul-behavior.66317/

I now switched to 80Mhz and will see if it's stay stable. And yeah I think I have to go through the pain of resetting all devices.


SSID: "backhaul"
noise: -88 dBm Channel: 100/80
BSSID: xx:xx:xx:xx:xx:xx Capability: ESS RRM
Supported Rates: [ 6(b) 9 12(b) 18 24(b) 36 48 54 ]
HE Capable:
Chanspec: 5GHz channel 106 80MHz (0xe06a)
Primary channel: 100
HT Capabilities: 40Mhz SGI20 SGI40
Supported HT MCS : 0-31
Supported VHT MCS:
NSS1 Tx: 0-11 Rx: 0-11
NSS2 Tx: 0-11 Rx: 0-11
NSS3 Tx: 0-11 Rx: 0-11
NSS4 Tx: 0-11 Rx: 0-11
Supported HE MCS:
80 Mhz:
NSS1 Tx: 0-11 Rx: 0-11
NSS2 Tx: 0-11 Rx: 0-11
NSS3 Tx: 0-11 Rx: 0-11
NSS4 Tx: 0-11 Rx: 0-11
160 Mhz:
NSS1 Tx: 0-11 Rx: 0-11
NSS2 Tx: 0-11 Rx: 0-11
NSS3 Tx: 0-11 Rx: 0-11
NSS4 Tx: 0-11 Rx: 0-11

Interference Level: Acceptable
Mode : AP Only

DFS status: state In-Service Monitoring(ISM) time elapsed 14545050ms radar channel cleared by DFS channel 100/80 (0xE06A)

Channel Information
----------------------------------------
Channel 100 A Band, RADAR Sensitive
Channel 104 A Band, RADAR Sensitive
Channel 108 A Band, RADAR Sensitive
Channel 112 A Band, RADAR Sensitive
Channel 116 A Band, RADAR Sensitive, Passive
Channel 120 A Band, RADAR Sensitive, Passive
Channel 124 A Band, RADAR Sensitive, Passive
Channel 128 A Band, RADAR Sensitive, Passive
Channel 132 A Band, RADAR Sensitive, Passive
Channel 136 A Band, RADAR Sensitive, Passive
Channel 140 A Band, RADAR Sensitive, Passive

Stations List
----------------------------------------
idx MAC Associated Authorized RSSI PHY PSM SGI STBC MUBF NSS BW Tx rate Rx rate Connect Time
xx:xx:xx:xx:xx:xx Yes Yes -48dBm ax No Yes Yes Yes 4 80M 1441.2M 1441.2M 04:02:01
xx:xx:xx:xx:xx:xx Yes Yes -65dBm ax No Yes Yes Yes 4 80M 1020.8M 864.7M 04:02:02
xx:xx:xx:xx:xx:xx Yes Yes -44dBm ax No Yes Yes Yes 4 80M 1921.5M 1921.5M 04:02:04
I see your 5Ghz-2 do not have channel 149-165 which no need to scan for radar. That's why it is not stable as maybe there are radars there.

It is rare in my area for the radar interference occur. So I can use DFS channel without interruption for a long time.


SSID: "XXXXXXX Backhaul"
noise: -87 dBm Channel: 100/160
BSSID: XXXXXXXXXXXXXXX Capability: ESS RRM
Supported Rates: [ 6(b) 9 12(b) 18 24(b) 36 48 54 ]
HE Capable:
Chanspec: 5GHz channel 114 160MHz (0xe872)
Primary channel: 100
HT Capabilities: 40Mhz SGI20 SGI40
Supported HT MCS : 0-31
Supported VHT MCS:
NSS1 Tx: 0-11 Rx: 0-11
NSS2 Tx: 0-11 Rx: 0-11
NSS3 Tx: 0-11 Rx: 0-11
NSS4 Tx: 0-11 Rx: 0-11
Supported HE MCS:
80 Mhz:
NSS1 Tx: 0-11 Rx: 0-11
NSS2 Tx: 0-11 Rx: 0-11
NSS3 Tx: 0-11 Rx: 0-11
NSS4 Tx: 0-11 Rx: 0-11
160 Mhz:
NSS1 Tx: 0-11 Rx: 0-11
NSS2 Tx: 0-11 Rx: 0-11
NSS3 Tx: 0-11 Rx: 0-11
NSS4 Tx: 0-11 Rx: 0-11

Interference Level: Acceptable
Mode : AP Only

DFS status: state In-Service Monitoring(ISM) time elapsed 20899050ms radar channel cleared by DFS channel 100/160 (0xE872)

Channel Information
----------------------------------------
Channel 100 A Band, RADAR Sensitive
Channel 104 A Band, RADAR Sensitive
Channel 108 A Band, RADAR Sensitive
Channel 112 A Band, RADAR Sensitive
Channel 116 A Band, RADAR Sensitive
Channel 120 A Band, RADAR Sensitive
Channel 124 A Band, RADAR Sensitive
Channel 128 A Band, RADAR Sensitive
Channel 132 A Band, RADAR Sensitive, Passive
Channel 136 A Band, RADAR Sensitive, Passive
Channel 140 A Band, RADAR Sensitive, Passive
Channel 144 A Band, RADAR Sensitive, Passive
Channel 149 A Band
Channel 153 A Band
Channel 157 A Band
Channel 161 A Band
Channel 165 A Band

Stations List
----------------------------------------
idx MAC Associated Authorized RSSI PHY PSM SGI STBC MUBF NSS BW Tx rate Rx rate Connect Time
XXXXXXXXXXXXXX Yes Yes -47dBm ax No Yes Yes Yes 4 160M 2722.2M 2882.3M 05:48:43
XXXXXXXXXXXXXX Yes Yes -54dBm ax No Yes Yes Yes 4 160M 2882.3M 2882.3M 05:48:45
 

tgl

Regular Contributor
At least in the USA, if you need to avoid the DFS channels then you must disable 160MHz channel bandwidth --- there are simply not any 160MHz channels that don't overlap the DFS range. Once you've done that, you might find that unchecking the avoid-DFS box will "stick". However, in my limited experience (I've only done this on the 42095 firmware), it's best to manually select a control channel 149 or higher (DFS range is 52-144). I saw the XT8s using DFS-range channels even when they claimed to be configured not to, so I don't trust that checkbox one bit.

The details of available channels might be a little bit different in other countries, but I think the channel numbering and the DFS range are the same everywhere.
 

rsnhakan

Regular Contributor
My 2nd node was also crashing and not performing as it should. Sometimes it would be totally useless (flashing blue light). I did send it to Asus. My main router had no problems. I was using Wireless backhaul.
 

chucker

New Around Here
@comlab I am having the exact same issue and curious if you had been able to permanently resolve this issue by switching to 80mHz? Thanks in advance.
 

comlab

New Around Here
@comlab I am having the exact same issue and curious if you had been able to permanently resolve this issue by switching to 80mHz? Thanks in advance.
Yes for me switching to 80mHz fixed the speed drops to ~100 Mbps, and the speed for the 3 nodes stayed stable. However I was annoyed that I could not benefit of the 160mHz speeds further since day one I had every few days very high ping spikes 1000ms+ between my router and the node in my Office. I'm spending my days most in Teams voice calls and whenever there was a spike over 30-60 seconds I dropped out of the meetings.

10 days ago I had enough and decided to rollback the firmware of the router and the 3 nodes to 42095 and reset the system with the wps button method. Ah few hours after the reset and the fresh setup (no restore of a backup) I had again the drop to ~100 Mbps, I almost went crazy. After that I fixed the speed 160mHz and a fix channel (100), since then I no longer had any issues. Fingers crossed! One thing I can say for sure, the high ping spikes are fixed with the older firmware.

My personal bottom line, dynamic Channel bandwidth setting on the backhaul is no working for me, and I will keep the setting either on 80 or 160mHz, that fixed for me the drop to ~100 Mbps issue. However since I have set setting on 160mHz I see the Radar Alarms again and since I reinstalled the system I had at least one drop to 80mHz again. After a reboot (I still reboot the system every few days) the speed was back at 160mHz and all was good. I'm also not sure if the Auto Control Channel setting is working fine, I definitively have less issues with a fixed channel, but hey that's my system. Who knows how other system in other environments are working. Two last things, First Asus Support was useless, I raised a ticket which went no where... Second, if the backhaul speed stays at 160mHz then it works very fast, unfortunately I'm not sure how reliable that Mesh system really is.

Greetings from Switzerland

Stations List
----------------------------------------
idx MAC Associated Authorized RSSI PHY PSM SGI STBC MUBF NSS BW Tx rate Rx rate Connect Time
xx:xx:xx:xx:xx:xx Yes Yes -42dBm ax No Yes Yes Yes 4 160M 3843.1M 3843.1M 64:52:40
xx:xx:xx:xx:xx:xx Yes Yes -48dBm ax No Yes Yes Yes 4 160M 2882.3M 2722.2M 64:52:40
xx:xx:xx:xx:xx:xx Yes Yes -68dBm ax No Yes Yes Yes 4 160M 1729.4M 816.7M 64:52:41
 

chucker

New Around Here
@comlab thank you so much for the response. I am going to implement the same steps and see how it goes. Looking on the asus website, I am not seeing any download links for the 42095 FW version. Can you please point me in the right direction to roll back my router and nodes?
 

comlab

New Around Here
@comlab thank you so much for the response. I am going to implement the same steps and see how it goes. Looking on the asus website, I am not seeing any download links for the 42095 FW version. Can you please point me in the right direction to roll back my router and nodes?
Looks like they pulled that from the support site, maybe because of the age. Still for me the 42095 is way more stable than everything I had since I bought it in November 2021. I googled for the file name and found a link:
However seems there is now a warning on the Asus Support site:
If your router's production year is 2022 or above, DO NOT downgrade to this version. Please check the back label for the production year.
 

velani

Occasional Visitor
I have been able to successfully upgrade to 46061. So far so good.

Guest network question: Is it possible to label the 2.4 and 5G bands of the guest network to have the same SSID? That way, the best band is awarded to the guest device rather than have to select which band to log into?
 

OzarkEdge

Part of the Furniture
I have been able to successfully upgrade to 46061. So far so good.

Guest network question: Is it possible to label the 2.4 and 5G bands of the guest network to have the same SSID? That way, the best band is awarded to the guest device rather than have to select which band to log into?

Yes, that is what Smart Connect band steering is suppose to permit.

OE
 

tonyfl

New Around Here
Helllo everyone! I have a random question.....

I bought a single XT8... Do in need to have AIMEsh on? or any of the backhaul setting on? I do not need another node in my house. Would i see increased performance?
 

RogerSC

Part of the Furniture
Helllo everyone! I have a random question.....

I bought a single XT8... Do in need to have AIMEsh on? or any of the backhaul setting on? I do not need another node in my house. Would i see increased performance?

Deja vu, seem to have seen this question before, recently *smile*.

No, AiMesh and backhaul settings are only for creating a mesh between your XT8 and other nodes, like another XT8 or other AiMesh-capable Asus router(s). If you only have one router, no benefit to trying to use those settings. Just leave them at their defaults.
 

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