We often receive requests from customers, explaining that their connection at some points "freezes", or they have a hard time getting a good signal strength even though they are connected near to the Access Point. Another scenario might be that clients start off with a good connection, but after moving between APs, the connection is unstable before it is lost.
These symptoms, generally speaking, are what we refer to as Roaming Issues.
It might be, that you are encountering an issue called "sticky clients". That is when the client stays permanently connected to an Access Point, due to the client not triggering a disconnection on very low signals. One way to compromise this issue is to set RSSI Thresholds. These can be set under Configuration > Object > AP Profile, editing a radio profile in "Show Advanced Settings"-Mode and scrolling down to the bottom. You will see "Station Association Threshold", which indicates the minimum RSSI level a client must have before he can connect, as well as "Disassociate Station Threshold", which indicates the minimum signal a client can have before getting disconnected by the AP.
The values set in here are highly individual and depend on your site. We, however, recommend values for Station Association around -70 dBm to -75 dBm, for Disassociation Thresholds we recommend ~ -75 to -80 dBm.
Select the option "Station Retry Count" to allow a wireless client to try to associate with the AP again after it is disconnected due to weak signal strength.
Here a screenshot for your reference:
If this does not help, you might consider checking the SSIDs Security profile. Since v4.30 firmware on our controllers, there is a new feature implemented called 802.11r (Fast Roaming). This standard will help you have an even faster and smoother roaming connection as you are used to have. However, this feature brings a few problems with it, and some clients might have some trouble. Also, some apps might have problems having this setup.
You can disable this function in the Configuration > Object > AP Profile > "SSID" - Tab > "Security Profile"-Tab > Doubleclick on the SSID Security Profile and deactivate the "802.11r" - Checkbox