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Occasional Contributor II
Posts: 38
Registered: ‎03-29-2013
Students and staff with Linux on WiFi

Hello,

 

We have been steadily upgrading our old AP-61/65/70 abg access points to 105/93H 'n' access points.
As this has happened the number of complaints from linux users has increased.


We cannot control devices that students bring on campus or the operating systems they choose to run.

 

In my own testing (using a single ap-group so all settings across AP's are the same), my test device was a thinkpad with an intel 1000bgn adapter running Ubuntu 12.04 LTS.

 

On our captive portal SSID on the 802.11n AP's linux performs fine.
On our dot1x wpa2-aes SSID on the 802.11n AP's linux connects, and the performance is terrible
On our dot1x wpa2-aes SSID on the 802.11n AP's, if I disable the 'n' rates on the linux host, the performance is good.
On our dot1x wpa2-aes SSID on the AP-61, linux performs fine.
On our dot1x wpa2-aes SSID on the 802.11n AP's with a specific USB 802.11n adapter (Ralink & tplink) I am told linux is fine (someone else tested that, I did not observer)

 

I would like to know if anyone else is having the same issues, or if there are any suggestions for me.

 

Thanks,

 

Matt

Contributor II
Posts: 41
Registered: ‎06-07-2010
Re: Students and staff with Linux on WiFi
I can tell you that I'm using Kali Linux on my Dell laptop with 802.11n AP-105, AP-125, and AP-135 all over our campus without issue. Is there any commonality with the client wireless cards? A peer institution of ours saw strange behavior similar to this but it turned out the clients had single radio adapters.
Occasional Contributor II
Posts: 38
Registered: ‎03-29-2013
Re: Students and staff with Linux on WiFi

For the affected cards.  I have asked now to get the card/driver but I don't have enough replies yet, thanks.

intel 1000bgn card is affected

intel wireless 5100agn card is affected

 

Occasional Contributor II
Posts: 26
Registered: ‎10-16-2008
Re: Students and staff with Linux on WiFi

We saw an issue that seem similar.  I found that the user could connect and stay connected to eduraom but not our campus SSID.  The only difference on the two was Bandsteering.  

 

The user disabled 11n (using the commands from the 3rd link below )and then worked fine.

 

Previous Thread on Community

http://community.arubanetworks.com/t5/ArubaOS-and-Controllers/Connection-Problem-in-Linux/td-p/4340

 

The user disabled 11n and then worked fine.

 

Here are the posts-

 

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/420678

 

 

http://ubuntuforums.org/showthread.php?t=2030227

 

 

Chris Hart

Northwestern University

Contributor II
Posts: 41
Registered: ‎06-07-2010
Re: Students and staff with Linux on WiFi

Matt,

 

The first place that I would start is to see if there are any updated drivers available in a repository for these cards.

Occasional Contributor II
Posts: 38
Registered: ‎03-29-2013
Re: Students and staff with Linux on WiFi

Thanks for the suggestions.

On our two SSID profiles, both have band steering.  the dot1x profile is eduroam, and the other is our captive portal.
I will try a dev SSID without band steering and see if there is a difference.

For the drivers, a colleague more familiar with Linux than I has I think tried that, but I will double check.

Regards,

Matt

Occasional Contributor II
Posts: 38
Registered: ‎03-29-2013
Re: Students and staff with Linux on WiFi

Disabling band steering on the VAP did not help. 
The performance remains poor.


If i do pings to my gateway or to a website 

the pings happen fine for a few seconds, and then everything appears to stop for a few seconds.  (over and over)

New Member
Posts: 11
Registered: ‎12-13-2012
Re: Students and staff with Linux on WiFi

We had a problem with Linux users getting connected to our .1x or WPA2 PSK SSIDs but they could only send traffic for a minute or two at best.  Upgrading to 6.3.1.0 did not fix the problem (although we did get to start playing with AirGroup).  Here is what fixed it for us, right from the Aruba TAC:

 

"Upon further research found that there was a problem with client linux driver's MPDU aggregation mechanism and it's possible that somehow Linux MPDU aggregation (both in ath9k - atheros and Intel drivers in Linux) suffers this problem.

As a workaround, could you please try to disabled MPDU Aggregation in our controller configuration and please check the status of the client communication.

Under High-Throughput SSID Profile, we have the feature called "MPDU Aggregation". So could you plesae try to disable this " MPDU Aggregation" in the ht-ssid-profile, which will be inside of the SSID profile."

 

Good luck!

Aaron

Occasional Contributor II
Posts: 38
Registered: ‎03-29-2013
Re: Students and staff with Linux on WiFi

Thanks Aaron, 

I will try that.

Regards,

Matt

Contributor II
Posts: 146
Registered: ‎05-12-2010
Re: Students and staff with Linux on WiFi
[ Edited ]

I found a solution for Linux with Intel cards that works for some of my coworkers. Basically, you disable 802.11n speeds and the driver behaves reliably.

 

Here is a temporary solution that does not survive a reboot. 

 

sudo modprobe -r iwlwifi
sudo modprobe iwlwifi 11n_disable=1
Bruce Osborne - Wireless Engineer
ACCP, ACMP
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