ZenWiFi AX (XT8) as node - can you turn off second 5 GHz radio?

[Qbcd]

I know this is a weird question, but I am using my XT8 as an AiMesh node with an AX86U as the main router. And I would like to turn off the XT8's 2x2 5 GHz radio. The 4x4 5 GHz radio has plenty of bandwidth to provide the backhaul AND serve clients without a bottleneck as I only have a 100 mbps internet connection. So I don't want to have a separate channel being used, I am already using a 160 MHz DFS Channel 100, and where I am that actually has a higher legal power limit then the rest that's available, so for this and other reasons I don't want to use another channel on this network. I'm only giving this explanation because I know someone will ask why, but I'd rather not focus on the why please.

The problem is, when I go into the AiMesh menu and try to turn off either of the 5 GHz radios, the blue light starts blinking, blinks for a few minutes and eventually they both turn off. If I try to turn one of them back on, the same thing happens and then they both turn on. So it seems they can only be turned on or off together, you can't have one of them on and the other off.

My question is, is this normal or is there something wrong with my unit? Is there a way to make it work in node mode?

Thanks!

 

[tgl]

While in theory that should work, I'm not surprised in the least bit that such a configuration proves unstable. ASUS have a sorry track record for even getting the mainline use-cases to work reliably, never mind something that's off the beaten path. Maybe you'd find it works better with a different firmware release, but you may well be wasting your time pursuing the idea.

A more likely answer is to give the 5GHz-1 radio a different SSID/password and then just don't use that SSID.

Another idea is to run wired backhaul and then see if shutting down one radio will work.

FWIW, I have had success running an XT8 (f/w 42095) in AP mode with just one radio turned on to talk to a single client (another XT8 in media-bridge mode, serving only wired clients). That's worked for me with either 5GHz-1 or 5GHz-2 as the active radio, but I found 5GHz-2 performed a little worse in terms of ping latency, so I'm currently using 5GHz-1. Although it's been gratifyingly stable since I got it configured correctly, getting to that point was a nightmare --- notably, no f/w release later than 42095 has worked well. And I can't say how well it'd work with ordinary clients, nor if I tried to run the remote node in AIMesh rather than as an independently-configured media bridge. (So maybe the correct advice is "forget AIMesh, configure the nodes by hand"?)

 

[Qbcd]

While in theory that should work, I'm not surprised in the least bit that such a configuration proves unstable. ASUS have a sorry track record for even getting the mainline use-cases to work reliably, never mind something that's off the beaten path. Maybe you'd find it works better with a different firmware release, but you may well be wasting your time pursuing the idea.

A more likely answer is to give the 5GHz-1 radio a different SSID/password and then just don't use that SSID.

Another idea is to run wired backhaul and then see if shutting down one radio will work.

FWIW, I have had success running an XT8 (f/w 42095) in AP mode with just one radio turned on to talk to a single client (another XT8 in media-bridge mode, serving only wired clients). That's worked for me with either 5GHz-1 or 5GHz-2 as the active radio, but I found 5GHz-2 performed a little worse in terms of ping latency, so I'm currently using 5GHz-1. Although it's been gratifyingly stable since I got it configured correctly, getting to that point was a nightmare --- notably, no f/w release later than 42095 has worked well. And I can't say how well it'd work with ordinary clients, nor if I tried to run the remote node in AIMesh rather than as an independently-configured media bridge. (So maybe the correct advice is "forget AIMesh, configure the nodes by hand"?)

Thanks for the reply.

So I pretty much spent the whole day testing it and I've concluded that there is no way to make the 5GHz-2 work as fronthaul using AiMesh. If you set up the XT8 as a repeater, then it does work. I don't want to do that however, mainly because AiMesh's roaming is better among other reasons.

I tried older firmware - I bought a twin pack that hadn't been updated since version 386, so I tried the second unit before updating the firmware. And that did actually let me turn off 5GHz-1, however all that did was force 2.4 GHz for the clients, it did not let me use 5 GHz-2 as fronthaul. Besides, I don't want to run old firmware.

I can't pick SSID with AiMesh, I can't even set the fronthaul channel for 5GHz-1, which I also learned is limited to channels 36-64 (not mentioned anywhere in specs). And I can't run wired backhaul, but I tested it that way and it didn't make any difference.

Since I don't want to run in repeater mode, I guess I will just accept that clients will have to use the other band. Luckily, it seems that by default, the XT8 uses channel 52+ for 5 GHz-1, which is DFS and what I would use, otherwise 36-52 are obviously super congested. And 5GHz-2 only does channels 100-140, but that's fine because it's what I need it for anyway.

Since it works in repeater mode, there's no reason they can't make it work in AiMesh, it's just a firmware limitation, but they probably don't care enough to fix it... It's so dumb because I would much rather use Channel 100 with 4x4 and 160 MHz for my fronthaul. Channel 100 has a higher power limit, you get 2 more radio chains and double the bandwidth. Yes, you also cut the available bandwidth in half because you're using the same band for backhaul and fronthaul, but for slower internet connections it doesn't matter. And if they're gonna force you to use the other band for fronthaul, they should let you pick the channel.

Anyway, rant over. I'll just use it as intended...

 

[tgl]

... If you set up the XT8 as a repeater, then it does work. I don't want to do that however, mainly because AiMesh's roaming is better among other reasons.

Interesting. For me, AIMesh's roaming was in the "barely works at all" category --- that's the key reason my XT8s got demoted to point-to-point duty from being the main house net. Did they improve it in the last year? When I was using it, it could hardly have been any worse in the separately-configured-repeater case.

Since it works in repeater mode, there's no reason they can't make it work in AiMesh, it's just a firmware limitation

Agreed, the hardware could probably do this just fine. Have you tried Merlin's firmware (well, it'd have to be GNUton's version)?

 

[Qbcd]

Interesting. For me, AIMesh's roaming was in the "barely works at all" category --- that's the key reason my XT8s got demoted to point-to-point duty from being the main house net. Did they improve it in the last year? When I was using it, it could hardly have been any worse in the separately-configured-repeater case.



Agreed, the hardware could probably do this just fine. Have you tried Merlin's firmware (well, it'd have to be GNUton's version)?

Well based on my research, in Repeater mode, no roaming happens at all. Clients just hold onto the network until they lose signal and only then reconnect. I have been using AiMesh with older Asus routers and roaming works pretty well, definitely not perfect, but it works, and you can adjust the RSSI at which clients switch, but I've just left mine on default and it seems to work well. But I have no experience with XT8s, I just assumed they would work the same or better... now I'm a little worried after what you said, so we'll see...

No I haven't tried Merlin, don't really want to to be honest as I don't need any of its features. But if it enables repeater usage of 5 GHz-2 on the XT8 in AiMesh mode, maybe I'll consider it. I doubt it does. I hope Asus eventually enables this functionality, I'm not holding my breath...

 

[Qbcd]

And you know it just occurred to me that if my AX86U ever switches from Channel 100, as it does a few times a year to Channel 52 - I'm 99% sure it's not because of a radar event but some firmware glitch - then the XT8 will actually switch to 2.4 GHz backhaul and stay there until I notice it and fix it.

Because the 5 GHz-1 cannot be used for backhaul, and 5 GHz-2 can only do channels 100-140. So it will use 2.4 GHz, despite having two perfectly good 5 GHz bands, which I'm sure have the hardware capability to do all legally allowed channels. How dumb is this... And of course the AX86U (or any Asus router) lacks the ability to auto-switch back to the set channel after a certain period of time.

Honestly, this combined with the inability to select fronthaul channel... is making me think I should stick with my old AC66U B1. At least there I know what channel will be used, I can use the higher power Channel 100 for fronthaul, and I know it will always use 5 GHz backhaul. But unfortunately it can't really do more than 200 mbps with my setup.

It really boggles the mind how these expensive routers fail at so many basic things, I keep discovering basic functionality that is lacking... Should be no brainers to fix, but Asus works in mysterious ways.