LAP1042 register to wrong controller

[Ingénierie RCI]

Hi

We facea problem with LAP1042N terminals, which suddenly try to register a bad controller after running normally.

They are on a 2500 controller and we have installed a C9800-CL to migrate to new access points on site.
The addition of new terminals is underway but will not be finalized for several months.

The C9800-CL controller is in version 17.6.4, it normally does not allow to use LAP1042Ns in this version.
The 2500 controller is in version 8.3.143.0.

Do you have any idea why the terminals are trying to reach the other controller? They have the IP of the 2500 registered.

I remain available for further testing or verification.
Thank you in advance

Regards.

[Mark Elsen]

 - It's not advisable to have two controller active in the same capwap broadcast domain (anyway)  ; for the time being isolate the C9800-CL , also have the APs using DHCP option 43 to find a controller  , 

 M.

[MHM Cisco World]

https://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-lan-wlan/97066-dhcp-option-43-00.html

As @Mark Elsen mention op43 is solution here.

Config op43 for LAP1042N different than other AP' and hence the dhcp server will send back different wlc IP for each AP.

MHM

[Rich R]

It sounds like you might have all your APs and WLCs together on the same broadcast domain (subnet/vlan) which means they will discover the new WLC via broadcast regardless of HA and option 43 settings?

This is why it's best practice to keep them separate and use option 43 for discovery.  Keep old and new APs on separate VLANs so that option 43 for old APs only points to old WLC and option 43 for new APs only points to the new WLC.

[Leo Laohoo]

1042 is not supported in 9800.

The last firmware 1140/1042 are supported is 8.4.X.X and 9800 will not support that version.