Wireless Management Interface IP change after rebooting or switchover

[Shiden]

Hello all,

I recently configured a physical WLC C9800-L-F. 

Here are some details about the WLC that could be useful:

Model: C9800-L-F-K9

Firmware: Bengaluru-17.6.4

I configured two Switched VLAN Interface. One of them is used as management interface in VLAN 10 (IT-MGMT) and the other one as Wireless Management Interface in the VLAN 25 (WIFI-MGMT). I have manually set the WMI with the command "wireless management interface VLAN 25". Until this point, every thing is working well. The WMI has the IP of the VLAN 25 interface, and the access points are able to joint the WLC. 

Now my problem is the following. When I reboot the WLC or a swtichover is triggered, the IP of the WMI change from the interface VLAN 25 IP to the interface VLAN 10 IP. This leads to a lost of all access points (113 in our case). HA SSO is configured on the WLC and the RMI Interfaces are also configured on the VLAN 10. I don't if there can be a relation with the RMI link.

Here is the configuration of the WLC if that could help:

vlan 10
name IT-MGMT
no shut
vlan 25
name WIFI-MGMT
no shut
!
interface Vlan10
ip address 10.243.0.13 255.255.255.0 secondary
ip address 10.243.0.12 255.255.255.0
no shut
!
interface Vlan25
ip address 10.243.7.5 255.255.255.0
no shut
end
!
wireless management interface Vlan25
chassis 2 renumber 1
chassis 1 priority 2
chassis redundancy keep-alive timer 6
chassis redundancy keep-alive retries 8
conf t
redun-management interface vlan 10 chassis 1 address 10.243.0.13 chassis 2 address 10.243.0.14
management gateway-failover enable
!
redundancy
mode sso
main-cpu
standby console enable
end

Does anyone know why this happens? Can this be fixed or is there a workaround?

I already say thanks to the people who will take time to answer this post.

Best regards.

[marce1000]

                 - Did or do you always save the configuration when making config changes ? 
  Also have a checkup of the  (current active) C9800-L-F-K9 configuration with the CLI command show tech wireless
  Feed the output into :                                                                                 https://cway.cisco.com/wireless-config-analyzer/

 M.

[Shiden · Accepted solution]

Hi @marce1000 ,

Thank you for your response. The wireless-config-analyzer has been very helpful in improving the configuration of the WLC. The reason for the previous issue was that the RMI interfaces and wireless interface needed to be in the same VLAN. After moving the RMI interface to VLAN 25, the problem was resolved. I am not sure if this configuration is mandatory or if it is just a bug, as it is not clearly mentioned anywhere in the cisco documentation that the RMI interfaces and wireless interface must be in the same VLAN.

[marce1000]

                >...The wireless-config-analyzer has been very helpful in improving the configuration of the WLC
   Great to know! Note that it is advisable to use the config analyzer on a regular basis , after (new) configuration changes , and also after upgrades (for instance). Also regular use on every 2 months,  you may also get reports on changes in the RF environment , 

 M.