Solved RT-AC87R iPad Air 2 intermittently dropping connections

[Sky]

Greetings, everyone.

I am running RT-AC87Rs with the current ASUSWRT FW at two locations setup in nearly identical ways. One of the clients is an Apple iPad Air 2 running iOS 12.0. This issue happens at both locations. I've searched the forums and the internet to the best of my ability, but have not seen this issue elsewhere.

The device works OK evenings, weekends, and generally after 1500 hrs PDT M-F. It's used for trading and on days of high stock market volatility between 0600-1400 hrs +/- it can't hold a connection until internet traffic slows. On low volatility days it's good for maybe 45-min at a time. There are 15-25 clients connected to this router at any given time, and 30-some odd networks broadcasting in the immediate areas.

I've been fighting this for years now. Traceroutes and extensive work with the broker, ISPs, etc., led to a node between me (CA) and the broker (CT) being replaced, but no real help for me.

I've been trying to educate myself on the myriad options available in the ASUSWRT but I am totally stumped. Something I read pointed to the DTIM Interval (3) & Beacon Interval (100) both possibly causing this sort of behavior, but trial-and-error is limited to days and times when it is failing and when experimenting is strictly verboten due to the obvious risks.

I haven't seen anything in the modem logs suspicious (SB6183), nor in the routers logs that I can see. I do understand the DTIM would only matter if the device was in power saving "sleep" state, which I would not think it would slip into while the user is actively browsing and writing orders, but -- Apple is special -- so I suppose that might be a possibility.

Any help or hints greatly appreciated.

Sky

 

[ApexRon]

Are both locations using the same SSID?

On iPad: Settings/WiFi turn on “Ask to join networks”

On iPad: Settings/WiFi/‘SSID name’ select I with circle around it and turn on ‘Auto-join’

 

[Sky]

Are both locations using the same SSID?
On iPad: Settings/WiFi turn on “Ask to join networks”
On iPad: Settings/WiFi/‘SSID name’ select I with circle around it and turn on ‘Auto-join’

ApexRon, thanks for responding.

I probably confused this by mentioning the multiple location thing. This issue is not location specific, it is intermittent. iPad joins the network(s) seamlessly when within range, no issues there.

1. Yes, both locations use the same SSID
2. "Ask to join networks" is turned off forcing any "not known" joins to be done manually vs. being "asked" to join. "Ask" is more convenient, but this forces a small work step on my user to reinforce security considerations before joining an unknown network.

My workaround for the disconnects has been to use the cell phone as a hotspot which works reliably in both locations and eliminates PEBKAC, iPad, ISP, transmission routes, and (?) destination servers -- thus my conclusion the problem is in the way I have the router(s) setup.

That said, there certainly remains a possibility the destination server(s) lack bandwidth on heavy days but they do have a huge ($B/$T) incentive to ensure failsafe server rollover. Which brings me back to --- me and my setting up of the routers.

I really hate intermit-tent problems!

P.S. In case it's of any use:

• throughput appears to be OK (300 Mbps location 1 / 100 Mbps location 2 both meet or exceed contract);
• connectivity of other devices is OK;
• other devices do not drop connection;
• the iPad only drops intermittently on this one single site -- which unfortunately happens to be a hugely critical site to remain solidly connected to; and
• ethernet desktops & wifi laptops connected to this site do not drop their connections.

 

[GuruGuy]

Greetings, everyone.

I am running RT-AC87Rs with the current ASUSWRT FW at two locations setup in nearly identical ways. One of the clients is an Apple iPad Air 2 running iOS 12.0. This issue happens at both locations. I've searched the forums and the internet to the best of my ability, but have not seen this issue elsewhere.

The device works OK evenings, weekends, and generally after 1500 hrs PDT M-F. It's used for trading and on days of high stock market volatility between 0600-1400 hrs +/- it can't hold a connection until internet traffic slows. On low volatility days it's good for maybe 45-min at a time. There are 15-25 clients connected to this router at any given time, and 30-some odd networks broadcasting in the immediate areas.

I've been fighting this for years now. Traceroutes and extensive work with the broker, ISPs, etc., led to a node between me (CA) and the broker (CT) being replaced, but no real help for me.

I've been trying to educate myself on the myriad options available in the ASUSWRT but I am totally stumped. Something I read pointed to the DTIM Interval (3) & Beacon Interval (100) both possibly causing this sort of behavior, but trial-and-error is limited to days and times when it is failing and when experimenting is strictly verboten due to the obvious risks.

I haven't seen anything in the modem logs suspicious (SB6183), nor in the routers logs that I can see. I do understand the DTIM would only matter if the device was in power saving "sleep" state, which I would not think it would slip into while the user is actively browsing and writing orders, but -- Apple is special -- so I suppose that might be a possibility.

Any help or hints greatly appreciated.

Sky

Given the odd hours of the issue, I would think of this as a software issue. You don't say what you are using for stock trading on the iPad; is it Safari browser or an installed app? If it's an app, is the user able to surf the web on the iPad when the issue is occurring?

 

[ApexRon]

ApexRon, thanks for responding.

I probably confused this by mentioning the multiple location thing. This issue is not location specific, it is intermittent. iPad joins the network(s) seamlessly when within range, no issues there.

1. Yes, both locations use the same SSID
2. "Ask to join networks" is turned off forcing any "not known" joins to be done manually vs. being "asked" to join. "Ask" is more convenient, but this forces a small work step on my user to reinforce security considerations before joining an unknown network.

My workaround for the disconnects has been to use the cell phone as a hotspot which works reliably in both locations and eliminates PEBKAC, iPad, ISP, transmission routes, and (?) destination servers -- thus my conclusion the problem is in the way I have the router(s) setup.

That said, there certainly remains a possibility the destination server(s) lack bandwidth on heavy days but they do have a huge ($B/$T) incentive to ensure failsafe server rollover. Which brings me back to --- me and my setting up of the routers.

I really hate intermit-tent problems!

P.S. In case it's of any use:

• throughput appears to be OK (300 Mbps location 1 / 100 Mbps location 2 both meet or exceed contract);
• connectivity of other devices is OK;
• other devices do not drop connection;
• the iPad only drops intermittently on this one single site -- which unfortunately happens to be a hugely critical site to remain solidly connected to; and
• ethernet desktops & wifi laptops connected to this site do not drop their connections.

I believe that because of the number of other WiFi in close proximity that the iPad may be attempting to connect to another WiFi. The iPad settings need to be reviewed at the time and place of failure making sure that all other networks do not have "Auto-Join" turned on. Off hours may work because one or more of the other WiFi is turned down.

Yes, I see now that I was wrong about "Ask to join networks".

I agree with @GuruGuy.

 

[Sky]

Given the odd hours of the issue, I would think of this as a software issue. You don't say what you are using for stock trading on the iPad; is it Safari browser or an installed app? If it's an app, is the user able to surf the web on the iPad when the issue is occurring?

GuruGuy, thanks for joining.

IB (Interactive Brokers), using the most recent [stable] IB app.

That's what I and IB Tech Support thought it might be too, but we've been fiddling with this off-and-on over the past few years through various iterations of their software, and their settings including http v https, etc. Nothing seems to "stick". The intermittent nature of the issue makes a repair look good until the next time heavy trading traffic occurs again — then all bets are off.

UPDATE: I forgot to mention IB Tech Support & Development say ours is the only user they're aware of with this issue. I see no reason to doubt them, really.

If it's an app, is the user able to surf the web on the iPad when the issue is occurring?

I have to say yes… or no. When the issue rears the app times out for 18-sec then tries to reconnect. If it fails to reconnect it loops and does that again until stopped by the user. If the user halts the reconnect, internet is normal. (Yes?) If the user does not stop the reconnect, during the time out the user is unable to exit the app nor to switch to another app, including the home screen, etc. (No?) The user can force out by holding the power button and forcing a total shut down, but that doesn't help nor answer if the user would be able to access the internet during that 18-sec window. So I can only guess here that access would/is working in the background but the user does not have direct interaction. If the app is functioning normally, the user can switch out by simply double-tapping the Home button, and use whatever app they want. However, the app logs the user out once it no longer has the focus, so when they switch back they must login again. This ensures device security, a really big deal especially when dealing with this broker as they cater to and execute for other brokerages. (Really big numbers here). So I suppose I should say I think so but I'm not sure.

UPDATE: During one of today's failures my user remained connected but was receiving no data stream on WiFi and incomplete data stream when connected to the cell hot spot. This led me to try changing the Wireless > 5 GHz > Professional : DTIM/Beacon settings in the off chance the bandwidth may be getting maxed based on my reading here: https://routerguide.net/dtim-interval-period-best-setting/. I really question if the small amount of bandwidth consumed by the beacons or wake-up+beacon would interfere enough to cause this, but it seems to be about the only shot I have left.

Default for 2.4 & 5 GHz is 3/100, or broadcasting the wake-up DTIM every 3rd beacon transmit which is set to occur every 100 ms. 2.4 GHz was left at default. 5 GHz was tested at 2/600, 1/300, 1/600, and 1/1000. At 3/1, 2/6, & 1/3 no data was received, at 1/600 partial data came in and the same occurred at 1/1000. 5 GHz was set to 1/600 and the test stopped awaiting further incidents.
​

I miss AM radio!

 

[Sky]

I believe that because of the number of other WiFi in close proximity that the iPad may be attempting to connect to another WiFi. The iPad settings need to be reviewed at the time and place of failure making sure that all other networks do not have "Auto-Join" turned on. Off hours may work because one or more of the other WiFi is turned down.

ApexRon: Yeah, I'm wondering about that too; I have another user on an HP laptop doing routine work on the LAN, not trading. This user was suffering intermittent drops at site A, and less frequent but still happening ones at site B that were not tied to any particular internet site, surfing, or being on the LAN, rather "all of the above". Reviewing the number of networks broadcasting SSIDs in the area, and their relative strength of signal inside our facility, we turned down the HP and the problem resolved.

Unfortunately, I don't know of any way to "turn down" the iPad and both routers need to reach some distance over multiple floors to cover the structures. I suppose in one way that's good because I can pursue the issue in either place.

 

[Sky]

UPDATE:
Wireless > Professional
Setting each band (2.4 & 5) to DTIM Interval 3 & Beacon Interval 600 appears to have greatly alleviated — but not solved — my problem on all but the weirdest of days.

Naturally during this trial-and-error period my most affected user finally (after years) decided to become competent at using the LTE network via their cell phone as a hotspot to quickly switch over in times of trouble. Not like that complicated my efforts — at all.

I also found it helped when I stopped blocking my user from the 5GHz band, an inadvertent but temporary issue that arose when making some recent security adjustments. Now if I can just find somebody to help me with this giant hole in my foot.

 

[Sky]

UPDATE: 21-FEB-2020

Ignorance being less blissful than it used to be for me when somebody else was doing all of the work and I could just yell about it then go fishing, I decided to dig a bit deeper into some of this stuff. The cats at BlueGadgetTooth (what a name) posted a nice little primer in channel-bandwidth relationships here: https://bluegadgettooth.com/channel-bandwidth-20-40-80/. So I looked at it. I mean, why not? It seemed reasonable to take a peek.

Now armed with better intel, I ran WiFi Analyzer from my laptop and discovered not only lots of WiFi networks in the area (gasp? really? I'm shocked! Shocked!) but that my beloved routers appear much, much better at auto-selecting bandwidth than auto-selecting channels.

The router chose non-standard ch-10 on 2.4GHz, with 20MHz. It's been working ok, mostly, so I tweaked it. Set it to a very uncrowded and very standard ch-1 and left the bandwidth at 20/40. Then I checked 5GHz. It was auto/80/auto/auto and the router chose ch-36 at 20MHz. Ch-36 is the most crowded in my location on the 5GHz spectrum, so I tweaked it too.

Yesterday my trader reported getting bounced off again so I checked things out and discovered if you change the bandwidth — but not the channel — and apply it, the router defaults the channel back to auto. So now, on my desktop which has a NIC and wifi and bluetooth and green hair(!), I ran inSSIDer and saw all sorts of noise. So I set the 5GHz to a very uncrowded ch-48 at 20MHz. Now it has a tight channel spread and no interference. I'll post the results in about a week or two after reasonable real-world time to see if it actually works.

Fwiw, I prefer WiFi Analyzer over inSSIDer, but the free versions do pretty much the same things. They are both available in the Microsoft Store, App Store, and Google Play.

 

[Grisu]

WinFi Lite is the best for W10: https://www.snbforums.com/threads/winfi-lite-new-wifi-analyzer-tool-for-windows.59181/
For now you have to use install-version, MS-Store may come back someday.

 

[Sky]

Is there a way to set the 52:64 range of channels in the 5.2GHz band on the Asus RT-AC97R? I'm using ASUSWRT and it only allows Auto, 36:48, and 149:165. In my area the 52:64 range would be ideal, the others being for ICM.

 

[Grisu]

If you dont see them there is no way, limited by firmware depending on region even if there is no reason for it.

 

[Sky]

WinFi Lite is the best for W10

Using now. That is a very nice utility indeed!

The RT-AC87R using stock ASUSWRT fw limits the 5.2GHz channel selections to Auto/36:48/149-165. Nothing from 52 to 144 is selectable, which is unfortunate because I have gobs of totally free channels in the 52:144 range and 149:165 is supposed to be for ICM.

My earlier post was not displaying, I thought it got lost in cyberspace.

1. Is there a way a novice can set one of those 52:144 channels?
   
2. Are those channels available in Merlin?
3. If I switch to Merlin will I still be able to use the Asus iOS apps? (Asus Router, Device Discovery, and AiCloud<-- Yes per Merlin:About)
4. Is Merlin 384.13_4 equivalent to, or up-to-date with ASUSWRT 382_51939?
5. Can I use the Asus-Merlin fw with my 'R' or do I need to do that script thingy and change it's name to 'U'? <-- No per Merlin:About

 

[Grisu]

Merlin wont change anything regarding to Wifi.
Merlin uses stock firmware as base, so his last firmware wont be back, sometimes he even implement fixes before Asus.

Ususally you cant be wrong in using his instead of stock (maybe in the past when he didnt support Aimesh).

 

[Sky]

I notice using WinFi Lite that it crashes under Windows 10 Pro x64 v1909 for all filter menu items beginning with Network Filter [SSID's] and going down the list. At least on my system. Every option for those 7 out of 8 menus under Network Filter crashes.

I notified the author but was wondering if anyone else has experienced this?

 

[Grisu]

I am still running WinFi Lite 1.0.0.0 for Windows on x64-system and no problems.
He might correct it with updates as you cant download older versions.

 

[Sky]

UPDATE: 03-JUN-2020

I think I can safely say this issue is RESOLVED. After all of the incremental improvements noted at the beginning brought my user to 80% stable, the final bit came from using the sniffers to settle on the best Wi-Fi channel, then using the System Log > Wireless Log to measure throughput from various locations in the building and relocate her within the building. Now her connection is up essentially 100% of the time Comcast's is up.

Thank you @ApexRon, @GuruGuy, and @Grisu!