Poor Wi-Fi calling. Clients associating to various APs.

[kdawilson]

We had to enable Wi-Fi calling to resolve particularly poor mobile coverage around our office. While this largely solves the problem we have a couple of offices that are located equidistant between multiple APs.

These users have complained about poor calls, and calls dropping.  I suspect that the clients are roaming between APs and this is consequently dropping calls.  I have proven this by putting a temporary AP into the person’s office, afterwards call reliability is fine. 

Cisco Prime Association History confirms devices roaming between multiple APs even within a 60 second period.   RSSI values range between -52 to -71 on the joined APs.

Do we have any control over this?  Is there an obvious solution that would resolve this?

Thanks

[balaji.bandi]

as you mentioned static client fixed in one location not have issue. as you also mentioned roaming only issue.

so you need to provide information as below :

1. what WLC

2. what AP

3. what code running

4. how is your config

5. have you done any troubleshoot using one client by enable debug ?

6. what is end client ? Mobile, what models ?

some guide lines :

https://www.cisco.com/c/dam/en/us/td/docs/wireless/controller/technotes/8-6/Enterprise_Best_Practices_for_iOS_devices_and_Mac_computers_on_Cisco_Wireless_LAN.pdf

[kdawilson]

Hi Balaji.Bandi,
Thanks for the reply and for the link. My WLC knowledge is quite basic.
We run two WLC 9800 in redundancy mode, with only C9115AXI APs. Version 17.3.4c
The only troubleshooting I've done is to put and AP into the office where the phones are used. When the AP it is that close it stays associated throughout. I will see if our Managed Service company (or TAC) can enable and interrogate debugging logs.
We use iPhones, all recent models.
Regards
Keith

[balaji.bandi]

Either you need provide the config here or contact TAC for investigate,

is this SD-Acess or OTT deployment ?

SD-Access - DNAC you see more assurance data and suggestion to fix the issue.

WLC 9800 also you can do debug.

[marce1000]

 - -  Review the 9800 (master)  configuration with the CLI command : show  tech   wireless , have the output analyzed by  https://cway.cisco.com/tools/WirelessAnalyzer/  , please note do not use classical show tech-support (short version) , use the command denoted in green for Wireless Analyzer.               Checkout all advisories!  This tool can also make you aware of the RF environment such as coverage holes , APs under heavy load , APs undergoing frequent channel changes and so on. It is advised to use WirelessAnalyzer on a regular basis,

                          For proper physical  wireless coverage make sure that a site survey was done (first!)

M.

[kdawilson]

Hi Marce1000,
Thanks for this, it looks very useful.
We had an Ekahau Site survey completed before purchasing the solution.
Regards

[balaji.bandi]

Personally i do not see this is the issue with site survey, this is more of behaviour of client when you roam...apple do have some issue of fast roaming, but this can tweaked depends on requirement.

since this is only issue with wifi calling, required to capture information like debug logs.