Wireless Access

Hi there,

We are a schoolboard and were are using aruba for the wifi since two years.
We have a master-local environment (M3 ArubaOS 6.1.2.4 Build 30768) and all our access points AP-105 are in tunnel mode.

Yesterday, I was in one of our schools where some Chromebooks were having issue connecting to the wifi

network (WPA2-AES).

When in the classroom and all the thirty Chromebooks powered-on. I can see that twenty-one are connected to the AP

that is installed in the classroom and the others are connected to neigboor APs.

After doing some troubleshooting, we found out that the Chromebooks that are connected to neigboor APs are having

issues (low speed). All Chromebooks were connected to 802.11a band and high-throughput is disabled.

My question is, what makes a device to connect to a far AP with a low signal rather than the nearest AP with strong signal?

What do you advise me for this type of deployment (thirty devices and one AP-105)?

Best regards,

I think you should look at a couple of things:

- Your AP placement deployment (How close are these APs to each other)

- What type of wall structure do you guys have?

- The min/max EIRP (power) set under the ARM settings

- You should probably consider adding 20/25 value in the local probe threshold under the SSID profile (in AOS 6.3 you can take advantage of using ClientMatch)

Hopes this helps

Read the HD VRD here if you havent...

http://www.arubanetworks.com/resources/reference-design-guides/

Cheers

Carlos

Hi Victor,

Thanks for your response.

just to add more details to my initial post.

All the APs for that school are in the same AP-Group.

- The distance between APs is approximatively 25ft 

- Wall : Brick 

- EIRP: 6/12

- Band steering: Enable / Steering mode: Prefer-5Ghz

- Spectrum loadbalancing: Enable / mode:Channel

- Airetime Fireness: Disable

- Local probe Threshold: Disable

Regards,

First try disabling Spectrum load balancing I have seen some issues with that enabled , is there a reason you have this enabled ?

And then take a look at these :

- Enable Airtime fairness

- Make sure you drivers are up to date

- You could try adding an SNR of 25

Do you have one AP per classroom ?

Hi Victor,

Thank you for helping with this issue.

I think disabling Spectrum load balancing will help me a lot in preventing Chromebooks from connecting to neighbor APs. This is my issue in these case. Ap-105 should be able to support 30 Chromebooks. This is a primary school and all my devices are Chromebooks, so Band steering will also help but not Airtime faireness (which was disable).  

All these Chromebooks are upgraded to the last version, so it'is not a driver issue.

SNR, is not recommended in a high density environment.

We have one AP per classroom.

I will do some tests with Spectrum load balancing disabled when I have chance to be at the school.

regards,

• is the band-steering  active
• is the load balancing active
• is the mix/max EIRP the same in the two AP (if they do not belong to the same AP group).
• how many user are configured to be supproted by the VAP.
• and as muntioned before , in the version 6.3 and  later you can take benifit of the ClientMatch feature witch can help you to reslove this probleme (http://www.arubanetworks.com/pdf/solutions/TB_ClientMatch.pdf )
• the probleme my be in  the Chromebook  !!!!