RSSI values constant at -75 to -85 dBm

[deepak george]

Hello Experts,

We recently did a site survey and added more AP's and also changed the position of the existing AP's based on the survey results.

We noticed two strange issues.

1>MAC book users located around 10Ft away from the nearest AP has constant RSSI values around -75dBm to -85dBm. We are currently running the latest Apple OS firmware on the laptops, however Windows laptops works well, the RSSI values are around -55 to -67 dBm.

What could be the issue here and how do i proceed further.

2>At another location we see a similar problem as stated in the first issue, however this time the RSSI values are bad for Windows and Apple laptops. The nearest AP is around 7 FT away.

The current WLC code we are running is 8.3.143

The channel utilization is between 10-15% and the number of users connected to the AP is around 10-15 users.

The Tx power levels of the AP is set to Auto and the current tx values are 2* and 3*.

The survey vendor blamed it on thee client machines,  however i do not buy that.

Thanks for all your help

[Scott Fella]

Well the surveyors job was to place AP’s to where it meets the RSSI and SNR for the requirements. However, they should also be knowledgeable on the devices on the network and or suggest configuration change. In the end, the devices make the decision on roaming.

What I would do from what you have provided, is makes sure that you have disabled the lower data rates. First try to have 24Mbps the lowest mandatory rate and 18Mbps and all the above on supported. Disable the rest of the data rates. Also review the number of clients on 2.4GHz and 5GHz. You want to have majority of your clients on 5GHz if possible. If you are seeing equal amounts or let’s say more than 10%-20% are 2.4GHz connected and devices are dual band, it’s time to look at your TX Power settings and or Client Band select values. With data rates, you can always increase the lowest mandatory rate to shrink the cell down, which will help make the devices roam to the nearest AP. Give that a try, but don’t forget to review your client count per band as that typically will help with users complaining about slowness and identified to be connecting on 2.4GHz vs 5GHz.

[deepak george]

Hello Scott,

Thank you so much with all your valuable inputs.

95% of the clients are on 5Ghz as we suggest them to use that.

The current data rates on 5Ghz radio are

18Mbps-Mandatory

From 24Mbps it is set to Supported

As suggested by you, i will set 24Mbps as Mandatory

The client roaming parameters are set to default

PS: The clients are stationary and never roamed during this period

[Scott Fella]

I would also make sure that the TX power isn’t very high. That is something you can also adjust to help shrink the cell. If you look at the TX power in dbm, make sure that the 5GHz is at least 3dbm higher than on the 2.4GHz. I always try to have at least 6dbm.

When you say that you tell the users to go on 5GHz, do they manually make the adjustments? If so, then what would happen if they weren’t told? The percentage would be higher on the 2.4GHz? This is where comparing what the TX power on both bands would help to understand how sparse or dense the environment is.

Also check the client counts per AP. This can also be a reason why devices don’t roam. You should try to have 25 clients or less on an AP.

I have both Windows and Macs and I don’t have this issue at all. Even at home which is like my lab, all my devices are connected within the -65dbm. This includes IOT devices also.