AP won't join to new controller pair. Stuck at old one.

[louhe]

Customer has two Ha-pairs of 2504. Now the first ones license is becoming full. I need to move some of the ap's from first HA-pair to second.

Network layout is pretty simple. HA-pair 1 is at network same network with ap's with ip 192.168.91.0/24. Second HA-pair is at network 192.168.92.0/24. Both networks has different DHCP pool. No DHCP options in use.

When i change untagged (native) vlan (network) from 91 to 92 AP gets right ip address after reboot but is assosiated to controller at .91 network. I tried to configure High Availability controllers under AP but it did nothing. Same thing, after reboot AP is back at .91 controller even if it has .92.x ip (and .92 controllers as high availability). So conclusion is that AP stores info about the controller somewhere and even high availability config does not bypass this.

Only way to get the AP to new controller is to reset it to factory defaults. This option takes long time and i wouldn't want to do the change this way.

So am I doing something wrong. Is there a way to change controller for ap just by rebooting it if it gets new ip address?

[Sandeep Choudhary]

Make sure to configure on AP "High Avlailability" with WLC-2 details entered as the Primary Controller.  This will force the AP to join the correct controller:  WLC-2.

APs are in local mode or flexconnect mode ?

Regards

Dont forget to rate helpful posts

[louhe]

Thank you for the reply.

I have already done this. So ap is at .91.21 controller (wlc-1-ha) even though it has Primary controller ip 92.20 & secondary ip 92.21 (wlc-2 & wlc-2 HA) configured under high availability. AP also has ip from 92.x network so somehow ap uses L3 adaptation without DHCP option or high availability config.

AP's are at Flexconnect mode.

[Leo Laohoo]

So what happens if you take change primary WLC details to .92 to a single AP? Does this AP go to .92 controller?

[louhe]

Nothing. I have already done that. Normally AP's do not even use that setting because controllers use L2 adaptation. So basically i have ap with ip 192.168.92.x/24 at controller with ip 192.168.91.x/24. Ap has primary controller 192.168.92.20 and still it sits at 192.168.91.20. Only if i factory reset the ap it will change the controller (without primary controller setting though).

[patoberli]

Do you have not enough licenses enabled on the second pair?

[louhe]

Yes, I have 50 ap license and only 10 in use.

[patoberli]

As far as I remember, an AP will always first try to connect to its previous WLC. Only if that fails and it somewhere gets the information about the other possible WLCs, it will choose another one.
In your case though, as you have manually configured both WLCs into the AP configuration, I'd assume it would try the second, once the first one fails. The APs don't do that?
Can you maybe show us the output from an AP while it's booting and trying to connect? Give it some 10 minutes of trying time.

[pieterh]

WLC-pair 1 sits in the same network as the AP's

WLC-pair-2 is in different subnet as AP's

you do not use DHCP option

you do not use DNS entry

Look at his sequence of WLC discovery:

1. Broadcast on the local subnet
2. Local NVRAM list of the previously joined controller, previous mobility group members, and administrator primed controller through the console port
3. Over the Air Provisioning (OTAP) (subsequently removed in version 6.0.170.0 code)
4. DHCP Option 43 returned from the DHCP server
5. DNS lookup for "CISCO-CAPWAP-CONTROLLER.localdomain"

so it will allways find the local subnet controller first

-> put the AP switchport in vlan10 or vlan20

- configure dhcp option for vlan10 in WLC1, WLC2

- configure dhcp option for vlan20 in WLC2, WLC1

so the local broadcast will not be succesfull, and the WLC is found by DHCP option or preconfigured primary/secondary

[louhe]

@pieterh if the controller is found via broadcast it should found the right controller. This is because they are at the same subnet at L2. So somehow AP uses L3 adaptation and discovers it old controller. So it must be that AP stores information about the old controller somewhere.

[louhe]

@ patoberli I suspect the same thing, that AP stores information of the old controller somewhere and it remember that info even after reboot. Even though the manual states that it does the broadcast on local subnet first.

Unfortunaly im only admin for this network and its real location is somewhat far, so I can't get the output from the bootup

[patoberli]

Can you enable SSH access plus a username/password on the AP and then reload it? Maybe the boot log is stored in the local logfile (show logging), although I somewhat doubt it.

Are the two WLC in a mobility group and if yes, has none of the WLC pairs "Master Controller" enabled?

[louhe]

Didn't find any log related to this.

There were Master controller enabled but removing it did nothing. Only that some of the ap's are now at HA-controller (but still at .91 network).

[patoberli · Accepted solution]

Check this here: https://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-lan-wlan/70333-lap-registration.html#anc8
Do you maybe not have the correct SysName or ip configured on the AP for the WLC und High Availability? The SysName must match, it's actually more important than the IP address.

[louhe]

That did it. I have slightly different names at .92 controllers. And when i used exactly same sysname as in under Controller -> general - > name I got ap's to change the controller. I didn't know that the name was also factor when choosing controller. Always though that it is only ip that matters.