[Android Q&A, Help & Troubleshooting] surfrock66:
I've got kind of a strange WiFi issue I've been working through for almost 6 months, and by process of elimination, I'm beginning to actually wonder if it could be an Android/Google bug. Only google devices seem to be impacted. I'm gonna overshare information here so that my troubleshooting steps can be audited; sorry if it's a long post. I’m open to any and all suggestions, but I’ve worked through this a ton and am pretty frustrated.

I have a pretty spread out house, so we made the decision to install 3 AP's, one in each far corner upstairs and one in the middle downstairs. Each one has the same SSID, so roaming should work. They’re on channels 1/6/11, all running at 2.4Ghz. I also am a pretty involved linux sysadmin, I have a home server running Ubuntu Server; I call it the HDA which runs my DHCP and a DNS server (and an iperf2 server). I have comcast business class to my house. The network topography is outlined below as best I can, all with Cat6e cables:

SMC Gateway (SMCD3G-CCR)

Minecraft Server (Dell Poweredge SC1425)

HDA Ethernet 1 (Dell Poweredge SC1425)

24-Port Switch

HDA Ethernet 2

Living Room 5-Port Gigabit Switch (TP-Link TL-SG105)

Living Room AP (TL-WA01ND; Channel 1) (Used to be ​​Edimax EW-7228APn; Channel 1)

Xbox-360

Office Desk 5-Port Gigabit Switch (TP-Link TL-SG105)

System76 Wild Dog Performance

Attic 8-Port Gigabit Switch (TP-LINK TL-SG108)

Master Bedroom AP (Edimax EW-7228APn; Channel 6)

Theater Room 5-Port Gigabit Switch (TP-Link TL-SG105)

Theater Room AP (Edimax EW-7228APn; Channel 11)

Xbox-One

I have a bunch of wifi devices as well:

System76 Darter Laptop (Debian Sid)

Google Nexus 5 (Android 5.1, TWRP, Rooted, used to be on 4.4 as well)

Samsung Galaxy Tab 10.1 (Android 4.4.2)

4 Chromecasts

HP Work Laptop (Windows 7 Enterprise)

HP Wife's Laptop (Windows 7 Home)

Wife's Samsung Galaxy S3 (Android Jellybean) (INACTIVE)

Wife's Work iPhone 6

Wife's Work HP Laptop (Windows 7 Enterprise)

My DHCP server assigns all static IP's, and partitions things into 2 DHCP groups: primary DNS server pointing to the HDA and secondary pointing to google's DNS, or both primary and secondary pointing to google. All wired devices on the network perform flawlessly, and I've done repeated iperf tests from node to node to verify that the wired network works great, including wires to the APs.

So, now the issues. For a long time I operated under the belief that something was wrong with my setup, and I'm still open to that possibility. I had wifi connection issues on my darter laptop, on the chromecasts, and on the nexus phone. My work Windows laptop, my wife's home Windows laptop, my wife’s work iPhone, and my wife's work windows laptop work fine. After extensive troubleshooting of the network (I changed every setting on all the APs, I even swapped the living room AP out for the different one, and conducted an extensive wifi survey to find the best channel in each location) I discovered my darter laptop has a hardware flaw; the antenna for the wifi is directly under the keyboard, so having the laptop in your lap while typing on it causes dramatic wifi degradation (documented here: www youtube com watch?v=gDekZp3MFA8 ). I got a usb wifi adapter, and I've been golden ever since.

The issue itself: I’ll be connected to the wifi network, and some sites will load fine, then suddenly I’ll try to load something like the reddit app, or twitter, or facebook, etc etc...and it’ll just load forever. I’ll try to upload a youtube video of my son, it’ll take 45 minutes to start, but then when it does it’s lightning fast. Most apps oddly don’t time out...some do; Marvel Puzzle Quest gives “check your connection” but I’ve let “Reddit is Fun Golden Platinum” think for over 15 minutes, and it never times out, which I’d expect it to do in a network-down kind of situation. Reddit is the biggest example, I can browse something like /r/pics and load 5 images from imgur flawlessly, then suddenly the 6th will just never load. Additionally, when I come home from work, I find that even when wifi is on, it rarely connects to my network...in the settings, wifi will have the little ! next to it, but if i just manually connect to the network it connects instantly. A couple of times on my nexus it gave me the “poor connectivity” exclamation mark while already on the wifi, but I believe I disabled that using this guide: android. stackexchange. com questions/100657/how-to-disable-captive-portal-detection-how-to-remove-exclamation-mark-on-wi-fi All the services are fine, because I’ll drop off wifi and switch to LTE and everything loads fine. If I iperf to my HDA by IP from the Nexus, I’ll get very mixed results...I’ll get no response whatsoever and a timeout, then disconnect and reconnect (landing on a different AP) and it’ll work, but slow, and repeat again with different results. It feels like there’s an intermittent thing going on where the device forgets how to wifi for a bit.

My work also has a multi-AP setup; tons of Cisco AP’s broadcasting about 6 APs. I have trouble connecting here with the Nexus 5 as well, it doesn’t auto-connect (going into wifi settings, it says “Wifi Connection Failure”), and when I do if it even connects it’s very slow...meanwhile my laptop is on the same wifi and it’s lickety split. This is trickier since I don’t control the services and can’t test as well, also things like websense are in play. Both at home and at work, the wifi worked fine before the upgrade from 4.*. I did some validation with the networking guys, from the radius side I’m golden, but at this point I don’t even try to connect anymore. (Actually, today, I tried on our unrestricted guest net as well, same message, “Wifi Connection Failure” and that’s our unrestricted network for patients...iphones sitting right next to me are fine)

Before, my wife's S3 worked ok, but it was time for it to be replaced and she got a Samsung Galaxy S6, then at the same time got a galaxy tab. The phone came with Android 5.0.2 and the tablet came with 4.4.2, and she’s now having wifi issues. Additionally, our chromecasts do the same kind of thing (though it’s harder to debug). I can cast a song from DSub off my LAN subsonic server, and it plays fine...then it goes to fetch the next song, and may just sit for 20 minutes...never times out, but just hangs. I’ve gone and moved ALL wifi devices having issues into the DHCP group which just uses google’s DNS to eliminate that as a factor, but it hasn’t helped anything. Screencasting or watching Netflix drop off the chromecasts constantly.

So I did some testing, to eliminate variables in the multi-ap setup, I performed an iperf test with my laptop and my nexus right next to each other after renaming 2 of my APs so there’s no roaming. I performed all these tests sitting in my living room, both devices using the same DNS settings and sitting about 18 inches from each other. Reminder, Master and Theater are pretty far away.

Test 1: Master Bedroom AP

Nexus 1: 10.4s, 384KB, 302Kb/s

Nexus 2: 20.1s, 640KB, 261Kb/s

Nexus 3: 11.5s, 1MB, 732Kb/s

Nexus Speedtest: 184ms, ...stopped saying “Network communication issues” mid test, so I re-ran, 27ms, 1.44Mb/s down, 0.10Mb/s up

Darter 1: 10.7s, 1.5MB, 1.18Mb/s

Darter 2: 11.0s, 1.88MB, 1.43Mb/s

Darter 3: 10.3s, 1.50MB, 1.22Mb/s

Darter Speedtest: 25ms, .81Mb/s down, 1.35Mb/s up

Test 2: Living Room AP

Nexus 1: 10.1s, 6.75MB, 5.63Mb/s

Nexus 2: 10.1s, 6.12MB, 5.07Mb/s

Nexus 3: 10.2s, 4.75MB, 3.92Mb/s

Nexus Speedtest: 31ms, 8.07Mb/s...stopped saying “Network communication issues” mid test, so I re-ran, 29ms, 17.50Mb/s down, 5.05Mb/s up

Darter 1: 10.5s, 6.12MB, 4.92Mb/s

Darter 2: 10.1s, 7.62MB, 6.31Mb/s

Darter 3: 10.3s, 6.75MB, 5.51Mb/s

Darter Speedtest: 18ms, 15.13Mb/s down, 7.68Mb/s up

Test 3: Theater Room AP

Nexus 1: 111.3s, 512KB, 37.7Kb/s

Nexus 2: 32.5s, 384KB, 96.9Kb/s

Nexus 3: 102.9s, 331KB, 26.3Kb/s

Nexus Speedtest: Too weak to successfully load speedtest

Darter 1: 24.6s, 384KB, 128Kb/s

Darter 2: 25.7s, 384KB, 122Kb/s

Darter 3: 30.0s, 512KB, 140Kb/s

Darter Speedtest: Too weak to successfully load speedtest

So, the network is consistent-ish across them all, but the speedtest thing is exactly what I seem to experience. It’s FAST FAST FAST dead FAST dead FAST FAST FAST dead.

I don’t know what else to do. I am posting here since it’s the Google wireless devices all doing this, I don’t have a single complaint from a wired device or a wireless linux/windows device. It’s the android and chromecast devices that are giving me hell, and other than this correlation I’m stumped. I don’t know how else to troubleshoot; I don’t want to have to replace the APs but if I need to I can try to talk the wife into it. Just to be complete, I’ve theorized and tested the following to no avail:

Roaming Threshhold - Eliminated multiple AP’s with same SSID, no improvement

DNS - Switched to google DNS for all clients, no improvement

Channel - Surveyed and changed channels, no improvement

AP make/model - Replaced one AP, no improvement

Home network connection - Tried at work, no improvement

I’ve attached my network topography stuff, I can provide DHCP and DNS configs as well if anyone thinks it’d be helpful.