topic Re: Client roaming issues on C9800 in Wireless

Client roaming issues on C9800

Ingénierie RCI — Mon, 18 Nov 2024 15:55:20 GMT

Hello,

We have a problem with a C9800 Wireless Controller (version 17.9.4a) and Cisco C9120 Access Points. Some clients are roaming from one AP to another, while there're not moving from their desk. For exemple, as shown in the exemple, a client in a meeting room is roaming among 3 AP in a short amount of time :

Even if the latency is high, the client decide to roam without moving.

The access points and the controller are in differents network, the C9800 is running on a virtual machine on Microsoft Azure.

All the AP are in Flexconnect mode, and the policy on the WLAN is only configured in Central Authentication :

We've modified the Data Rate on the RF-Profile, to force Access Point to disassociate clients with a poor rate from an AP, and force them to connect to a closer AP

Do you have any clue about why the client still decide to roam without moving.

I attach the "show-tech-support-wireless" file with the configuration and firmware information

Postscript : The device shown in the history is a updated Windows 10 Laptop.

Re: Client roaming issues on C9800

Mark Elsen — Mon, 18 Nov 2024 16:18:42 GMT

- Feed your attachment into : Wireless Config Analyzer
At least all red errors in the wlc checkresults (html view or excell) should be corrected , but review the other advisories too such as RF related.

+ Client roaming decisions are always autonomous , make sure the layout of the wireless network was done properly with wireless
site survey
- 17.9.x is becoming gradually EOL , consider moving on to 17.12.3

Re: Client roaming issues on C9800

Flavio Miranda — Mon, 18 Nov 2024 16:25:51 GMT

@Ingénierie RCI

As frustrating as it sounds, this is not a WLC or AP problem. Clients make the call on the roaming not the network. Update client driver to lasted and check roaming sensibility on the client wireless adapter.

Re: Client roaming issues on C9800

Haydn Andrews — Mon, 18 Nov 2024 23:01:09 GMT

Things like 802.11v and client loadbalancing could do it, however generally find that its related to client drivers or poor RF design

Re: Client roaming issues on C9800

Leo Laohoo — Tue, 19 Nov 2024 01:46:23 GMT

Is this happening to just one wireless client?

Re: Client roaming issues on C9800

Rich R — Tue, 19 Nov 2024 23:12:40 GMT

Enable Radioactive Trace for an affected MAC address while it roams and then feed the output into the Debug Analyzer (link below) to see how it looks from the WLC point of view.

But as the others have pointed out already, roaming is always a client decision so you need to look at why the client is deciding to roam (all the factors already mentioned by the others). Start by updating the client drivers to latest version before testing. For Intel: https://www.intel.com/content/www/us/en/download/19351/intel-wireless-wi-fi-drivers-for-windows-10-and-windows-11.html

Re: Client roaming issues on C9800

atila.kis11 — Tue, 23 Sep 2025 12:29:31 GMT

We had the same issue a while ago. Solved this whit changes on the client NIC.
Lowered the Roaming aggressiveness and lowered the TX power. That solved the issue for us.

Re: Client roaming issues on C9800

Ambuj M — Wed, 24 Sep 2025 15:30:02 GMT

check the log and confirm if you are seeing this CO_CLIENT_DELETE_REASON_DOT11_MAX_STA ?

recently had roaming issue reported, but we were hitting https://bst.cisco.com/quickview/bug/CSCwo37680

had a simple fix and then roaming worked like a charm.

Re: Client roaming issues on C9800

Bdas1 — Wed, 22 Oct 2025 16:15:17 GMT

What was the fix you made?

Re: Client roaming issues on C9800

aipan-zhao — Wed, 26 Nov 2025 10:03:07 GMT

Regarding this issue, I have encountered a similar problem now. Have you found a solution yet?