WLC9800 - no AP's joining

[Workshire]

Good day,

I have the following issue.

I am configuring a WLC 9800 -l-f device and have the issue that the Access port is not getting the config from the controller. The AP just boots up and then flahes red and green. I think it cant get a connection to the controller or it cant get an IP from a DHCP.

Can someone just verify the switchport settings and the WLC settings for me please?

vlan 20 is for the WLC management

vlan 22 is supposed to be for AP's only

vlan 19 is the guest wifi

Switchport settings:   Int gi1/0/10

                                  switchport mode trunk

                                  switchport trunk native vlan 20

                                  switchport trunk allowed vlan 20,22,19

WLC config:        vlan 20

                           name wlan mgmt

                          int vlan 20

                          ip add 192.168.10.2 255.255.255.240

                          ip route 0.0.0.0 0.0.0.0 192.168.10.1

                         wireless management interface vlan 20

                         vlan 22

                         name APs

                         vlan 19

                         name guest

                         int tw0/0/0

                         switchport trunk allowed vlan 19,20,22

                         switchport mode trunk

                         switchport trunk native vlan 20

       that's about it. I can access the WLC via webinterface and can start the zero day configuration and can add wifi network etc.

     I can ping the gateway and also have dhcp setup for the vlan 22 (AP's) but the AP is not getting an IP from the dhcp.

    The WLC is only connected via one cable from port tw0/0/0 to the switchport gi1/0/10

    they are both trunks and carry all of those mentioned vlans. I think either something is configured wrong here or maybe on the switchport where the AP is connected to.

The port on the switch for the AP is configured like this:

switchport mode trunk

switchport trunk native vlan 22

basically i am not sure why the WLC can not even "find" the AP so it can be managed by the wlc. Usually it is supposed to just work when you plug a new AP into t network socket with that config, the wlc should "discover" that new AP and then just load everything on it. But i can not get that far.  Am I doing something wrong? Even I didnt finsih yet the complete WLC setup (Zero day is finished), it should at least find the AP.

can someone please give me a hint. I worked on this issue for the last 3 days almost nonstop but cant figure this out.

thank you for your help

[marce1000]

        >...but do I need to add this configuration on only one switch where the wlc is connected to?
          -       That is unrelated only the APs need to be able to use and or find a dhcp server ,

 M.

[Rich R]

Like Marce says the DHCP server and the WLC are completely separate - they have nothing to do with each other.
The sole purpose of the DHCP server is to provide IP address, subnet mask, default gateway and option 43 to the AP.
Once the AP has that info it joins the WLC and after that the WLC provides the software and configuration to the AP.

[Workshire]

the weird thing is, the AP gets an IP address from DHCP. Helper Option 43 is set and in our firewall i can see that the AP contacts the WLC via Port 5246 ..but thats it. When i then check in the WLC if the AP is found, there is none.  Im thinking to re-do the HEX code of the helper address since maybe i made a typo there.

[marce1000]

         - Checkout : https://logadvisor.cisco.com/logadvisor/wireless/9800/9800APJoin
                                              for futher troubleshooting.

 M.

[Workshire · Accepted solution]

Just an update for everyone. The Issue was that the WLC were running Version 17.3 and with our AP's CW9164-l it needed to run at least Version 17.9.  After updating the WLC's, the AP's were all discovered successfully.  maybe someone can mark this as solution, at least this was the issue for me. Thanks all for your ideas and help.

[marce1000]

 - Good work ,note that   also after upgrades it remains useful to analyze the controller configuration with wireless analyzer : using the CLI command show tech wireless and feed that output into : https://cway.cisco.com/wireless-config-analyzer/
                             This is so good

 M.