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So you have just deployed your new shiny Cisco WLCs and you have been waiting for weeks for the cablers to install your APs as per your design and you are sitting there all excited as you can finally enable the switch ports that the APs are connected to but… Oh no, no APs are joining the WLC.
I have certainly been there in that situation and I am going to share with you my usual things to check and troubleshoot.
Firstly we need to understand the process and priority for Cisco APs to discover and join the WLC
AP Discovery Process:
Now we know the process we need to understand the different methods that APs can discover WLCs
AP-to-WLC DISCOVERY Algorithm (find as many WLCs as you can):
AP goes through ALL disocevry methods to see how many WLCs it could find before moving to join phase
Now we understand the DISCOVERY phase we can move on to the JOIN phase.
Now we understand the JOIN phase we can move on to the CONFIGURATION phase.
Once AP has successfully completed the configuration phase it should join the WLC – but, what if it doesn’t? Where do I start?…
(I am going to make the assumption that you have recorded all of your AP MAC addresses correlating to a hostname in a nice excel sheet.)
Ok lets start with the Olivia Netwon John (Physical):
Ok so we have verified that Olivia (physical – come on keep up kids) is ok and the AP has power and is most likely flashing red, blue & green on repeat. So what’s next? There is no right or wrong way for what order you do these following steps in but is important that we verify all of them.
If possible console on to the AP and view the output message – there could be some information here that makes it very obvious what the issue is. Whilst consoled onto the AP verify that AP has correct FW code on it. If AP is to be controlled by WLC it should be “lightweight” mode and “K9W8” in the FW version – if AP is to not be controlled by WLC should be “autonomous” mode and “K9W7” in the FW version.
Log on to the CLI of the WLC and do some debugs and look at AP join stats to see if we can get any indicators of what the issue may be.
“Show ap join stats detailed [AP MAC Address]” –
Now lets enable some debugs with the following commands
With these debugs enabled and filtered on the AP MAC address pay attention to the outputs as there may be some key indicators in there for what the reason the AP is not joining the WLC. Like this example below there was a country code mismatch which will look something like this:
Which leads me on nicely to what we can make sure is configured correctly on the WLC that will cause APs to not join:
Ok so lets move onto DHCP.
Last but not least – the firewall:
So that is it – my checklist of what I do if APs are not joining the WLC – I hope this post is useful for you guys!