Best way to set up wi-fi roaming for iOS / wi-fi calling

[Rgilm]

Hi, I have three Asus RT-AC66U routers set up on my home network, because unfortunately one router doesn't cover every part. They're running Merlin firmware, one is set in router mode and the other two in AP mode and connected by CAT 6. They all have both 2.4GHz and 5GHz enabled, and all with the same SSID.

There is always some delay when devices roam between APs, where connections are dropped for 15-30 seconds.

The problem is iOS devices seem to LOVE to roam, and whenever they do, wi-fi calling (via AT&T) drops out (permanently) and I need to switch airplane mode on/off manually to reinitiate the connection. My iPhone frequently chooses to roam anytime I have a good signal from two AP's, even if stationary. This results in lots of dropped calls and missed calls, since I live in the sticks and don't get cell coverage to my door.

I am somewhat network savvy, but I am really at a loss how to fix this. The fact that iOS devices don't give much useful wi-fi debugging information is frustrating here. Really, I'm only guessing that roaming is why wi-fi calling drops.

Is there some obvious problem with my setup that I am missing? Maybe less transmit power so there's less overlap? Maybe some kind of advanced setting needs tweaking? Or a per-MAC setting I can change for iOS devices only? Get some kind of prosumer AP's like Ubiquiti sells?

Thanks for any tips...

 

[Stevemcclure]

I don't know if it will help but have you tried turning off WIFI assist on you iOS devices? Settings - Mobile data. Right at the very bottom.
With this on if you're wifi signal becomes weak it will automatically start using mobile data instead of wifi. It could well be switching between that before it switches back to a stronger AP.

I also use roaming, but on 2 AC87u's. WIFI professional setting are Roaming assistance enabled, Disconnect clients with RSSI lower than -70 dBm.

My iOS devices seem to switch over very quickly from just observing the wifi icon, but I could not comment on wifi calls as I do not use it.


Sent from my iPhone using Tapatalk

 

[CaptainSTX]

I don't know if it will help but have you tried turning off WIFI assist on you iOS devices? Settings - Mobile data. Right at the very bottom.
With this on if you're wifi signal becomes weak it will automatically start using mobile data instead of wifi. It could well be switching between that before it switches back to a stronger AP.

I also use roaming, but on 2 AC87u's. WIFI professional setting are Roaming assistance enabled, Disconnect clients with RSSI lower than -70 dBm.

My iOS devices seem to switch over very quickly from just observing the wifi icon, but I could not comment on wifi calls as I do not use it.


Sent from my iPhone using Tapatalk

The OP stated they have cell service in his house so mobil assist will not help.

Since you are using AT&T contact them about getting a AT&T Cell Spot. You end up with a defacto mini cell tower in your home. Worked better for me than WiFi calling ever did and now I have the same setup with T-Mobil.

Once you have the cell spot turn of WiFi calling until you are someplace it is the only option to make a call.

 

[sfx2000]

I don't know if it will help but have you tried turning off WIFI assist on you iOS devices? Settings - Mobile data. Right at the very bottom.
With this on if you're wifi signal becomes weak it will automatically start using mobile data instead of wifi. It could well be switching between that before it switches back to a stronger AP.

Good call on WiFi Assist on the iDevice - try disabling that little feature and see where that goes...

One other consideration - 3 AP's in a standard size house is probably a bit much, try taking one of them offline for a bit...

 

[sfx2000]

The problem is iOS devices seem to LOVE to roam, and whenever they do, wi-fi calling (via AT&T) drops out (permanently) and I need to switch airplane mode on/off manually to reinitiate the connection. My iPhone frequently chooses to roam anytime I have a good signal from two AP's, even if stationary. This results in lots of dropped calls and missed calls, since I live in the sticks and don't get cell coverage to my door.

Are you certain it's ATT WiFi calling or perhaps FaceTime Audio - I've found FaceTime (even just using audio) to be fairly unfriendly to multiple AP setups, whereas ATT WiFi calling feature tends to be very robust...

Up in the "menu bar" do you see "AT&T Wifi", or just "AT&T" - and I would agree with the post above recommending perhaps getting an AT&T Microcell - they work wonders if one has relatively poor 3G/4G/LTE coverage...

 

[Rgilm]

Thanks everyone. I forgot to mention one other issue. Sometimes when the iOS devices roam, they drop the wi-fi connection entirely - and then pops up a message saying "invalid password" for that SSID. The passwords are the same for all AP's and they're all WPA2 Personal. But somehow, something (either the AP's or the device) gets confused, until I airplane mode it.

When wi-fi calling is active, "AT&T Wi-Fi" is listed as the cell network. When it's not enabled, I get "No service"

I don't use FaceTime audio as I don't usually call other people with iPhones.

The AP's are all on different channels. Maybe I should try putting them all on the same channel? I don't expect a lot of traffic.

 

[gatorback]

Have you tried decreasing the transmission power \ relocating transmitters so as to minimizing overlap? What corrective action have you tried?

It sounds like this is more of an IOS problem: is this a problem with other handsets?

 

[Puppa]

Roaming assist on the professional tab will likely help, but you may need to play with the disconnect rssi values. -70 for 5GHz and -60 for 2.4GHz are good starting points.

Sent from my SM-N920V using Tapatalk

 

[sfx2000]

Thanks everyone. I forgot to mention one other issue. Sometimes when the iOS devices roam, they drop the wi-fi connection entirely - and then pops up a message saying "invalid password" for that SSID. The passwords are the same for all AP's and they're all WPA2 Personal. But somehow, something (either the AP's or the device) gets confused, until I airplane mode it.

I'm assuming that the two secondary "AP" are in fact configured as AP's and not as routers (easy to miss), and the other thing...

Try doing a full reset of the network settings in the iPhone, might be some cruft hanging out from previous builds/iOS releases...

 

[Rgilm]

Thanks again everyone. After spending a day fiddling with the settings mentioned above, my "give up" solution is to change the SSID of each AP to something unique (2.4GHz/5GHz still have the same SSID on each AP) and limit iOS devices to the most central AP.

I also replaced an ethernet cable that was giving about 20% packet loss. This seems to have fixed the "invalid password" problem, as iOS seems to report "invalid password" if it could not renew DHCP after roaming. But it didn't seem to fix the wi-fi calling dropping out.

I am not sure if the problem is iOS only or not. I think that iPhones are more likely to be carried around between AP areas, so they roam more often. Also, I always experience some connection interruption on all wi-fi devices when they roam, I think this is unavoidable.

And laptops don't usually have persistent connections like AT&T Wi-fi (which is really a persistent IPSEC tunnel) which get interrupted and don't reconnect. If the AT&T Wi-fi tunnel was aggressive about reconnecting, would not be as big a problem.

 

[PolarBear]

Someone mentioned here a while ago that roaming between different APs when using VoIP applications functions better if hardware acceleration is turned off.

I can't find the post right now, but I think it was in the last 6 months.

 

[sfx2000]

I also replaced an ethernet cable that was giving about 20% packet loss. This seems to have fixed the "invalid password" problem, as iOS seems to report "invalid password" if it could not renew DHCP after roaming. But it didn't seem to fix the wi-fi calling dropping out.

One thing just came to mind - ensure that all the AP's in use are configured to use the same scheme for WPA2 - don't mix them...

If AP1 and AP2 - AP1 doing WPA/WPA2 and the other doing WPA2 only, that can cause some issues...

 

[Rgilm]

Thanks. I had to change the SSID of the 5GHz network as well, as iOS wanted to roam between 2.4GHz/5GHz on the same AP (with the same resulting issues). Now I have one SSID with one AP only on 2.4GHZ, and another SSID with 5GHz on one AP and 2.4GHz/5GHz on the other AP's. Finally, "AT&T Wi-Fi" is nice and stable.

Based on my reading, it seems some disconnect is unavoidable while roaming, unless you buy higher end Cisco or Ubiquiti hardware. Still, it seems like the disconnect period should be measured in hundreds of milliseconds, while I'm seeing 15-45 second disconnects.

It seems like something is triggering DHCP renews when roaming, possibly that has something to do with it. I think there's a lot more tweaking that could be done, but I just don't have a lot of time to experiment.

 

[sfx2000]

It seems like something is triggering DHCP renews when roaming, possibly that has something to do with it. I think there's a lot more tweaking that could be done, but I just don't have a lot of time to experiment.

Shouldn't get a DHCP renew - but something comes to mind - is the second Router/AP in Router mode, and still having a DHCP server running?

Also, might try doing a DHCP reservation for that iPhone, which might help somewhat..

(in my experience, Linksys, Netgear, and Apple support seamless hand up/hand down across bands without interruption - I'm fairly certain that Asus should be able to do this as well)

 

[tallytr]

Exactly the same setup, router/AP Cat6, had the same thing happen with our iOS devices (constant VOIP interruptions/disconnects), only solution for me was to set different SSID's for the 2 bands and manually connect to the 5GHz band, the signal is strong throughout the house and the speed much better than on 2.4GHZ, only using older iPhones on the 2.4GHz band...

Wish iPhone had a preferred band selector, keep 5Ghz band unless RSSI drops below certain value...our iOS devices mainly hang on to 2.4GHz band, only very close to router 5GHz was reliably selected....

 

[Rgilm]

The other two AP's are definitely in AP mode and not router mode; thankfully the firmware setup makes it crystal clear which mode it's in.

The only reasons I suspect it's doing a DHCP renew, are that I get a DHCPDISCOVER message in the log when a roam happens, and also there was about a 20% chance of dropping the connection entirely when I roamed onto the AP connected by the bad ethernet cable. So I assume that there is some kind of necessary traffic like DHCP that, if dropped, causes the roaming drop. But it is entirely possible I am wrong about this.

I am sorely disappointed with Apple on this, as there seems to be virtually no way at all to view Wi-Fi logs on iOS devices, as far as I can tell. Any hint at all to the problem would have helped a lot.

I only have the 5GHz network because it supports higher speeds than 2.4GHz, for transferring files between laptops. I don't have any neighboring network interference on 2.4GHz (heck I don't even get cell reception here...) so I don't mind all my iOS devices being on 2.4GHz.

 

[sfx2000]

The only reasons I suspect it's doing a DHCP renew, are that I get a DHCPDISCOVER message in the log when a roam happens, and also there was about a 20% chance of dropping the connection entirely when I roamed onto the AP connected by the bad ethernet cable. So I assume that there is some kind of necessary traffic like DHCP that, if dropped, causes the roaming drop. But it is entirely possible I am wrong about this.

The only time you should see a DHCPDISCOVER event is if the client has no idea where it is, so it reverts back into INIT state - so maybe you're not running everything with the same SSID and Passphrase, at least not intentionally... and double check to ensure that you've only got one DHCP server on the network...