iPhone drops wifi on lock screen and slow association

[Saus]

Hi all, I recently moved from a Netgear R7000 with XWRT (so in essence, the great Asuswrt-Merlin!) with various older routers as APs to an Asus RT-AC68 as main router, with two more of the same as APs.

I am running the laters beta of Asuswrt-Merlin on all three. Before continuing, I have to praise Merlin - both with the XWRT fork/port and this, I love your work and it is awesome the time and effort you put in. Thanks.

My problem: my iPhone 7 does not stay connected to the router or the APs: when on lock screen, it drops the connection and moves back to 4G. When I unlock, it takes 2-5 seconds to re-associate with the router.

I am only using the 5ghz band (other SSID, not used, for 2,4 ghz).

This behaviour is totally new - never had this with the R7000. I am also able to rule out the iPhone as culprit, because it does not do this on other wifis such as at my work. Nonetheless I did try all usual client side options such as forgetting network, resetting the iPhone network conf alltogether,...

On the router, I tried tweaking all sorts of things (although never had to before) such as radio from auto to N/AC only, 20-80 vs 80mhz, and all the 'professional' power save related settings. No luck in any combination.

So in essence two issues: disconnect by iPhone 7 client (on lock screen); slow (re-)association therafter.

Any help greatly appreciated.

 

[martinr]

You have 2 access points and also wireless enabled on your main router. Does that mean you have problems getting the signal spread throughout your home? 5GHz signals are more susceptible to degradation by walls and furniture than are 2.4GHz signals. Have you tried 2.4GHz?

Are the APs genuine access points and not repeaters? Do they broadcast the same SSIDs and the same channel numbers?

If the iPhone is left in one place, where there’s a strong signal (rather than moving about the house in your pocket, does it still drop the connection?

 

[Saus]

Thanks very much martinr. The problems occurs when staying put at the same location with the iPhone, close to the main router, so no roaming involved - and roaming is not the issue here. In that location, the iPhone will connect (and reconnect) to the main router only, as I can monitor.

Just to answer your questions, the APs are configured same SSID, different channels (non-overlapping). Signal strenghts calibrated for good roaming, and that does work well, as indicated above.

If I DO roam to one of the APs, with the iPhone unlocked, roaming works great. If connected to the AP, the same thing happens as with the main router - with the APs having the same (standard and professional) wifi-settings, except channel. Thus, the iPhone has a great connection, but disconnects when on lock screen and when unlocked, takes up to 5 seconds to reassociate - with the correct AP as indicated.

NB I had this exact setup before with R7000 as main router, RT-N66u as AP and WNDR3700v4 as the other AP, and all worked great without this issue. The only thing that changed is all hardware replaced by RT-AC68u............

 

[FreshJR]

Try disabling WMM APSD, under Wireless -> Professional
(Don't forget to do it on both channels)

It is a low power mode negotiation between the phone and the router.
Usually it doesn't drop the connection, but there have been incompatibilities reported between the router chipset and iphones with this specific feature.

No idea if either was patched to date. I run with it off.

 

[martinr]

Nice guide on WMM APSD

https://routerguide.net/wmm-apsd-on-or-off/

 

[Saus]

Thanks both, I did try this along the way, because I also theorised that my issue is somehow power save related - but probably NOT on both channels (as 2,4 ghz is not used by me for these devices at all as indicated, and it seems counterintuitive that a setting for 2,4ghz channel would affect 5ghz only operations).

I will give this a go tonight and report back.

 

[sentinelvdx]

As far as I remember when I had iPhones long time ago, WiFi will drop when on lockscreen and switch to 4G when on battery. The only way it'll stay with WiFi on with lockscreen is when it's connected to it's charger.

Sent from my SM-G935FD using Tapatalk

 

[martinr]

Thanks both, I did try this along the way, because I also theorised that my issue is somehow power save related - but probably NOT on both channels (as 2,4 ghz is not used by me for these devices at all as indicated, and it seems counterintuitive that a setting for 2,4ghz channel would affect 5ghz only operations).

I will give this a go tonight and report back.

Having read @sentinelvdx ‘s reply, I wonder did you search on the Internet to see if it’s an iPhone thing rather than a firmware one? I did a quick search and found this as the first Google item

https://discussions.apple.com/thread/8027390

I don’t know how relevant it is: I got to the bottom of the first page and realised I would lose the will to live if I continued with the other 28 pages.

 

[ColinTaylor]

As far as I remember when I had iPhones long time ago, WiFi will drop when on lockscreen and switch to 4G when on battery. The only way it'll stay with WiFi on with lockscreen is when it's connected to it's charger.

I remember observing the same behaviour when my wife had an iPhone 4. Typical Californian thinking, we'll save a little bit of battery power by routing all your data through the mobile network - What do you mean you have to pay for mobile data, doesn't everybody in the world have unlimited data connections?

 

[sentinelvdx]

The thing I mentioned seems to be present by reading that thread.... (I had iPhone 4 with iOS 4 and since then up to iPhone 5s with iOS 9), even happened that powersave feature with iPad Mini devices.
Maybe now on iOS you have like Android a way to keep it connected all the time.

Sent from my SM-G935FD using Tapatalk

 

[FreshJR]

I remember observing the same behaviour when my wife had an iPhone 4. Typical Californian thinking, we'll save a little bit of battery power by routing all your data through the mobile network - What do you mean you have to pay for mobile data, doesn't everybody in the world have unlimited data connections?

Apple is pretty aggressive with power save, so that being said, once the phone goes to deep sleep then all downloads/filetransfers/etc are terminated.

At this point, the data is only alive for push notifications.

Once the user accesses the phone, it will exit deep sleep and resume wifi if present. I see this as a great tradeoff/decision.

The push notifications in deep sleep barely use any data, but the power savings from this decision are immense.

I used the same settings for one of my LTE android tablets and this increased standby time from 2 days -> 10 days (I disabled wifi during sleep).

So it is not like Apple is draining even megabytes of data in LTE sleep. I respect their choices!

To my knowledge, apps are only allowed 10 minutes in the background. After that they are suspended and can only have sockets waiting for push notification. If it drops wifi, I am pretty sure it does it after all background tasks are suspended.

--

to get back on point

My iDevices do not have slow association, but I will keep an eye if they drop while in sleep.

 

[ColinTaylor]

At this point, the data is only alive for push notifications.

True I'm sure, but bear in mind my example was some years ago when some mobile data plans were more draconian. I could see on my bill that every hour or thereabouts it would transfer a few kB of data. Unfortunately the mobile operator had a "minimum charge per period" if any data was used. The end result was a very expensive bill. Fortunately things have moved on here, but I thought the experience typified the insular view of the world that Silicon Valley sometimes has.

 

[FreshJR]

True I'm sure, but bear in mind my example was some years ago when some mobile data plans were more draconian. I could see on my bill that every hour or thereabouts it would transfer a few kB of data. Unfortunately the mobile operator had a "minimum charge per period" if any data was used. The end result was a very expensive bill. Fortunately things have moved on here, but I thought the experience typified the insular view of the world that Silicon Valley sometimes has.

Ahh the old fashioned, lets round this up.... I remember those days.

Background data was always toggleable if I remember correctly, but keep wifi on during sleep was not.

Apple always prevents advanced configs, unfortunately.

 

[Saus]

Thanks all for thinking with me.

Saddly, I don't think the answer is here. Yes, I've read all those iPhone related theories and presumed solutions (reset on lock screen....) in the quoted threats, and the theory that iPhones and other mobile phones drop wifi when idle/on lock screen.

Unfortunately, all of that does not hold true. As stated, this behaviour is completely new in my setup with onle ONE variable changing: from a Netgear R7000 with XWRT, which of course is a port of Asuswrt-Merlin, to an Asus RT-AC68u with Merlin 384.3_beta2.

To explain a bit more, and why this is CERTAINLY new and anoying: until this weekend, when I changed routers, I unlocked and went into my app that controls a multiroom wifi system. It would immediately show the system and I could control it. Now, on lock screen instead if the wifi sign I see '4G' and when I unlock and go into that app it says "Wifi is disabled or disconnected, please connect to your wifi" - and after 2-5 seconds, the phone automaticalle reassociates with the Router and the app works. And note this app is just an example/why I notice and bother, I can't access any other local network resource either in those first seconds and in settings, I see the iPhone reassociating.

I have come accross one bug in the firmware while researching. Seems not to solve this, but still worth mentioning @RMerlin...

I noticed in the Asus Router app that it would NOT list both my networks, only the 2,4 ghz network, and offer me to define my 5ghz. I also noticed that for the 2,4ghz, only half my password was listed: up until the point where I have a comma "," in the password. Then it cut off.

Now for trial I removed the comma in the password and lo and behold, the app lists both networks with full passwords correctly.

So there is some mishandling in the firmware (or the Asus Router app) of passwords in the WPA-2 setup, it seems.

 

[Saus]

Thanks all for thinking with me.

(...)

Unfortunately, all of that does not hold true. As stated, this behaviour is completely new in my setup with onle ONE variable changing: from a Netgear R7000 with XWRT, which of course is a port of Asuswrt-Merlin, to an Asus RT-AC68u with Merlin 384.3_beta2.

(...)

Thinking progressing, so putting it in a reply rather than edit on purpose.

Actually, TWO variables changed for me: the hardware, but also the Asuswrt Merlin codebase, namely to 'NG'. XWRT is still on 380, so I jumped to 384 codebase at this same time. So that may be it, too.

To be sure, I had these same WPA2 passwords before and when on the R7000 and 380, that worked fine with the iOS Asus Router App.

So while the , in password variable does not seem causal to this problem - it sticks even with a simple alphanumeric pw - this indicates that some things changed in the code base around the wifi stack (out of my depth here...), the driver in the firmware, or...?

 

[ColinTaylor]

Unfortunately, all of that does not hold true. As stated, this behaviour is completely new in my setup with onle ONE variable changing: from a Netgear R7000 with XWRT, which of course is a port of Asuswrt-Merlin, to an Asus RT-AC68u with Merlin 384.3_beta2.

You have moved from the 380 codebase to 384 which is a major change. I suggest you go back to the 380 branch and see if that fixes your problem.

 

[Saus]

You have moved from the 380 codebase to 384 which is a major change. I suggest you go back to the 380 branch and see if that fixes your problem.

Thanks - but can I? I read somewhere there's no going back from 384 to 380? (Due to CFE?)

 

[ColinTaylor]

Thanks - but can I? I read somewhere there's no going back from 384 to 380? (Due to CFE?)

I don't think there's any problem going back to 380 for the AC68U, although you have to use recovery mode. I think it's only an issue for new models like the AC86U that never had a 380 firmware version.

 

[Jack Yaz]

I don't think there's any problem going back to 380 for the AC68U, although you have to use recovery mode. I think it's only an issue for new models like the AC86U that never had a 380 firmware version.

And like the 3200 where the nvram size was increased, I believe.

 

[Saus]

Thank you. Will certainly try, because in the meantime I did switch my R7000 on 380 codebase back in as main router - and the issue is gone when connected to that one.

When I have roamed to the APs, which are still RT-AC68u on Merlin 384 beta 3, behaviour is problematic as described.

So will move those latter ones back to 380 codebase and let you know. If that solves it, this may require attention from Merlin (Asus, in fact!).

Moving those back would also narrow the sleuthing, because:

• if the issue were gone, it must be associated to the codebase. Not the hardware, which will have remained the same, not dhcp, because that is not handled by those APs - so then it would have to be the wifi association process.
• if the issue remains, it must be associated with the hardware. The codebase is then the same as one with which it works fine on other hardware. And it would have to be the wifi association process, as that is the only thing handled by those APs.

Correct?

If so, the reductory conclusion is that the issue is in the wifi association, either as handled by the 384 codebase, or as handled by the Asus hardware (as opposed to Netgear) generally.

@RMerlin, has there been any change in driver used or firmware handling of wifi association/maintaining connection with clients?