Unifi Network Issues

[ataylor]

Hi,

 

 

We currently have 13 Unifi - UAP Pro AP's on our site.

 

 

I'm having an issue where around 10-15 or more laptops connect to our wifi everything starts to grind to a halt, there is very little bandwidth actually moving, it's like no devices are getting any Airtime. Transfer speeds drop to as little as 0-50Kb/s and we get latency spikes up to 3000ms & dropped packets. If I turn everything else off and run only a few laptops I get normal speeds.

 

 

The laptops in question all have Intel Wireless-N 7260 AP's (not capable of 5GHz).

 

 

All AP's & Wireless cards are on their latest drivers/firmware versions.

 

 

We need 30 laptops in total to be able to connect to one access point.

 

 

None of our AP's are close in proximity and they are split between channels 1, 6 and 11. I have tried setting them all to low power, I have tried Airtime Fairness and Bandsteering but nothing seems to be making a difference.

 

 

At the moment I'm leaning towards there being an issue with the network cards on the laptops but I don't have any other kit to test.

 

 

Any suggestions or help would be appreciated.

Edited November 14, 2017 by ataylor

[Blue_Cookeh]

Which model AP is it exactly? Would it be possible for you to try a 5GHz-only SSID?

 

How many SSIDs are you broadcasting?

 

Are there many other Wireless networks in range?

 

15 doesn't sound like a lot at all, we run carts of 30 off one UniFi AP without problems.

[XiJ]

You don’t have any of the AP’s linked together wirelessly? This happened to one of our installs. In effect ALL network traffic was flowing over a wireless link between two AP’s. Slowed things to a crawl!

[Meldrew]

Personally, I'd want to be running this on 5Ghz. 5Ghz capable cards are fairly cheap these days.

 

Have you checked the controller software to see if other devices are connecting to the AP too? Have you got lots of students with their phones connected too?

 

Meldrew

[Accura2k7]

Ok, so you have good AP's.... What switches are you plugging them in to? Sounds more like data throughput more than a AP issue!

 

My site is huge, we have 54 AC-PRO-EDU units, plugged into Unifi POE+ Switches and HP Aruba for the rest of the LAN... No issues at all.

[ataylor]

Which model AP is it exactly? Would it be possible for you to try a 5GHz-only SSID?

 

How many SSIDs are you broadcasting?

 

Are there many other Wireless networks in range?

 

15 doesn't sound like a lot at all, we run carts of 30 off one UniFi AP without problems.

 

1.

Our Laptops only run on 2.4ghz so forcing 5GHz is pointless

 

2.

Two SSIDs, one guest network, one WPA2 Network.

 

3.

I have gone around with WiFi analyzer, I can't see any overlapping channels on the AP I am using for testing

 

You don’t have any of the AP’s linked together wirelessly? This happened to one of our installs. In effect ALL network traffic was flowing over a wireless link between two AP’s. Slowed things to a crawl!

 

I'm not even sure how I would configure the AP's to do that on unifi.

 

 

 

Personally, I'd want to be running this on 5Ghz. 5Ghz capable cards are fairly cheap these days.

Have you checked the controller software to see if other devices are connecting to the AP too? Have you got lots of students with their phones connected too?

 

Meldrew

 

Purchasing 5Ghz cards is my next point of call, but I feel like there is an underlying issue that needs fixing regardless.

 

Students can connect but I can replicate this when students are not on site.

Edited November 15, 2017 by ataylor

[ataylor]

Which model AP is it exactly? Would it be possible for you to try a 5GHz-only SSID?

 

How many SSIDs are you broadcasting?

 

Are there many other Wireless networks in range?

 

15 doesn't sound like a lot at all, we run carts of 30 off one UniFi AP without problems.

 

Mostly plugged into these.

https://www.comms-express.com/products/netgear-gs728tp//?keyword=&campaign=706076820&ad=32267571090&ADtype=pla&Productcode=814413452&gclid=EAIaIQobChMIhfOF6JvA1wIVTrXtCh3jQw_CEAQYASABEgJuWvD_BwE

 

 

I don't think it is a throughput issue though as when the issue occurs, I can't get any device to transfer at a reasonably rate, its not like one device is hogging the bandwidth. One test took 40 mins to log 30 laptops on. The highest bandwidth user was 300mb, followed by 150mb then 20mb or less from there.

[chazzy2501]

ok, I'd hardwire a laptop to the switch and run 3 pings 1 to the nearest ap, 1 to the corresponding POE switch (management) and 1 to a server (for transfer testing). I'd then start connecting laptops (near to the local AP) and see which device starts to lag out first.

 

Are you using WPA2 with AES/CCMP only (best performance) and any VLANS? Have you tried data rate control. (I use it to prevent legacy devices connecting (so have minimums of 18mbit))

[ataylor]

ok, I'd hardwire a laptop to the switch and run 3 pings 1 to the nearest ap, 1 to the corresponding POE switch (management) and 1 to a server (for transfer testing). I'd then start connecting laptops (near to the local AP) and see which device starts to lag out first.

 

Are you using WPA2 with AES/CCMP only (best performance) and any VLANS? Have you tried data rate control. (I use it to prevent legacy devices connecting (so have minimums of 18mbit))

 

Will give this a go second period as the laptops are free.

 

 

 

On another note, I've just done some more testing with Acrylic Wi-Fi Home, its picking up lots of random home AP's around albeit at a very low signal. Could that be causing my problems?

[GuyJD]

I had this exact same problem with the same N 7260 Wireless card and UAP Pro AP's I tried absolutely everything I could think of but nothing worked, in the end the issue disappeared when I upgraded the laptops to windows 10.

[ataylor]

I had this exact same problem with the same N 7260 Wireless card and UAP Pro AP's I tried absolutely everything I could think of but nothing worked, in the end the issue disappeared when I upgraded the laptops to windows 10.

 

I've just had a very similar response from the unifi forum...

 

https://community.ubnt.com/t5/UniFi-Wireless/Unifi-Wireless-throughput-issues/m-p/2139279#M262139

 

 

The next question is, what cards should I buy?

[AlanD]

...I struggle to believe that those cards won't work...although I suppose there might be some compatibility issue with Unifi.....perhaps they are only draft "n" spec..... thinking they are really old if they don't support 5GHz...which makes we wonder what the spec of the rest of the laptop is like when spending money on replacing the wifi cards...

 

...And I assume you have the latest WiFi drivers...or perhaps experimented with even early WiFi drivers installed...and actually installed drivers downloaded - not simply let windows tell you it has the drivers...

 

Your access points don't support "ac" so its difficult to justify putting in cards that are "ac" unless you are also thinking of adding some Unify "HD" access point...sometimes its better to future proof....

 

You might pick up some cheap 2x2 cards on ebay....possibly even 2x2 with "ac" - although they won't be wave 2 "ac" capable as they cost a fortune and are difficult to get (and I know because I've tried).

[Michael]

According to Intel's site, these are dual band cards. Just 'n' rather than 'ac' but it would still work.

[Michael]

GuyJD's response is interesting - what OS are these notebooks running? Windows 7 or Windows 10?

[AlanD]

...I'm confused...OP said "not capable of 5Ghz" ...but looking the cards up - they are capable of 5GHz operation....so its definitely worth checking for band sterering - because unless the AP is in the classroom (assume OP has tested with this - to prove its not signal strength) there is often a tendency for band steering to push clients to 5Ghz - and connection rate (If AP not in same room) is then so poor - clients fall back to 24.4Ghz...and then AP drops connection in attempt to force client back to 5Ghz...

[ataylor]

@AlanD There are different revisions of this card

 

https://ark.intel.com/products/series/75620/Intel-Wireless-7200-Series

 

We have the bottom one on that list that is not 5Ghz compatible. At first I was confused as most references said our card should support 5GHz until i realised there was a non "dual band" version.

 

Forcing devices onto 5Ghz was one of the first things I tried, I still have it enabled for any other devices we have to reduce load on 2.4GHz.

Also - The spec of the laptops is fine, I5 Proccessor, 128GB SSD, 4GB ram

 

I have tried about 5 different driver/firmware versions on both the laptops & the AP's but no avail, currently I am just running the latest available drivers for both from the manufactures websites.

 

 

Edited November 16, 2017 by ataylor

[ataylor]

GuyJD's response is interesting - what OS are these notebooks running? Windows 7 or Windows 10?

 

Windows 7

 

My windows 10 build is close to roll out but I still have some work to do on it.

[ataylor]

I have have the laptops sat in the same room as an AP and the issue still occurs. Its not a signal issue.

[Mr_Jiminy]

Does the problem occur with the AP Transmit Power dialed down?

[GuyJD]

Just a quick note, the reason I upgraded to the Unifi AP's was because of this issue as it also happened on my old Netgear WNDAP350 and 360's, I'd get 10/15 laptops connected in a classroom and the rest would fail to get an IP I'd then disable and re-enable the wifi on one that wasn't working which would then get it back onto the network but it would then push one that was working off.

 

I assumed that it was because the Netgear system was almost 10 years old at this point that it was the issue as the laptops were only a year or so old core i3's but after spending £3k on new AP's I can safely say it's an issue with the Intel N 7260 cards.

 

I have no idea why the upgrade to Windows 10 solved the problem, I can only assume there is a difference in the drivers but every driver I tried on Windows 7 had the same problem.

[BKGarry]

Just a little thought.

 

The laptops don't have bluetooth switched on as well do they?

 

I remember having issues with 2.4ghz cards when BT is turned on.

 

I also had issues once of an erroneous machine startup batch file, it kept on running itself, so not high traffic but high latency because of lots of requests going through. The only way to see them was with Wireshark on the wireless network connected to the same AP as the Laptops

Edited November 16, 2017 by BKGarry

[ataylor]

Does the problem occur with the AP Transmit Power dialed down?

 

yes it does

 

- - - Updated - - -

 

Just a little thought.

 

The laptops don't have bluetooth switched on as well do they?

 

I remember having issues with 2.4ghz cards when BT is turned on.

 

I also had issues once of an erroneous machine startup batch file, it kept on running itself, so not high traffic but high latency because of lots of requests going through. The only way to see them was with Wireshark on the wireless network connected to the same AP as the Laptops

I'll go check this now, not something I recall doing, thanks.

[JackCPickup]

Have you run Wireshark on the network while the issue is occurring?

[sted]

its possibly worth checking the power saving settings on the wifi cards in device manager that can sometimes cause odd issues

[ataylor]

Have you run Wireshark on the network while the issue is occurring?

 

I have, but to be perfectly honest, i'm not entirely sure what to look for, nothing obvious stood out to me.