Laptop Connects to MR Access Points in Different Room or even Different Floor Reducing Performance

[johnyoo]

Hello,

At our school, we have staff and student laptops connected to MR32 access points.

Lately, we are noticing through the ap.mearki.com monitoring webpage that the mobile devices would connect to an AP in a different room or even on a different floor, which reduces stability and performance. Rebooting the AP seems to resolve the connection problem temporarily. 

The AP channels for each classroom are different and do not overlap. Their Target Power is set to 22 dBm. The AP SSIDs has an External DHCP server assigned, they are  bridged, and has layer 3 roaming

The disconnection problem seems to be happening more frequently these days. 

Any suggestions on possible solutions?

[ww]

Is client balancing enabled or disabled in the rf profile?

 Did you check the wireless  health for clues?

Maybe 22dBm is just to high for you environment. What dbm does the ap show?

For example Meraki classroom rf profile has max 17dBm.

https://documentation.meraki.com/MR/Radio_Settings/RF_Profiles#Default_Templates

[johnyoo]

Thank you, ww for your suggestion!

The overall wireless health from this past week has been healthy with 92% of clients successfully connecting.

It seems some devices have Authenicaition issues as their primary fail points.

We have the APs set to Client Balancing.

For additional info: we have Band Steering enabled for 2 of our SSIDs. The student devices are locked to 5Ghz. All SSIDs seem to be having this issue.

I adjusted the minimum connect speed to 12 Mb/s and will wait to see if there is stability improvement. I'll adjust the target power on the APs as well if the problem persists.

Is there anything else to check as well? 

[michael_g]

Since association and roaming decisions are mostly made on the client device, outside of the client-balancing feature on the AP, monitoring the transmit power on the deployment will be important.  Performing a validation site survey should help you analyze the cell overlap using a tool like Ekahau Pro or AirMagnet.  Ideally you want to influence the client device to associate to a specific AP or group of AP's within a specified area.  Unless one of the AP's is having network connectivity issues I would expect the transmit power is the problem since your student devices are locked to 5 GHz and still having issues.

[johnyoo]

Thanks for the info @michael_g !

We changed the AP's target power for the classrooms a couple of weeks ago to 20 dBm. It seems though the issue is still occurring with a smaller group of users now. 

We noticed that even though the AP's target power is set to 20 dBm, the actual transmit power with the problematic user device associations are shown to be 14 dBm. The other AP's transmit power is at 19 dBm.

Is there any way to override the actual transmit power of the AP to reflect the target power value?

[michael_g]

When you set the target power, that is the power setting the AP is going to attempt to use.  As I understand it, what would be limiting it to reach that power is the capability of the AP itself or regulatory domain restrictions.  Taking a look at the AP data sheet (last page), there are multiple data rates that the AP is limited to using 15 dBm as a maximum. It's possible your just hitting the maximum capabilities of the AP on the selected channel.  I HAVE noticed (in the past at least) that the dashboard will let me set a higher target power than an AP can support. 

If the client is connecting to another AP, maybe consider lowering the power of the other AP's instead? That may be what's causing your trouble device to jump to an AP in another room.

[PhilipDAth]

Set the minimum connect speed to 12Mb/s (if you have it set lower).

[johnyoo]

Thanks, PhilipDAth! I adjusted the minimum connect speed to 12 Mb/s. I'll see if that improves things.