I have a site running a bunch of Cisco 1240 APs, to a Cisco 5508 WLC on a remote site. It's all running well. Yesterday, I added a new PoE switch, with two new APs hanging from it, to the site. One of the APs came up, updated its IOS, and just worked from scratch out of the box (as expected).

The other one (from the same batch of APs, of the same age, with the same IOS, same everything) connected to the same switch, refuses to be seen. I have swapped ports on the PoE switch, and the AP that works, does so whatever port it's on, and the one that doesn't, doesn't whatever port its on, so its not a switch issue.

The APs both show link LEDs on the switch, and both show activity (flashing LEDs) when plugged in. However, the WLC doesn't see the AP in CDP (or anywhere else). When they start up, the APs get all their base information from DHCP, including WLC address(via Opt43), which works with all the other APs on the site.

I'm a bit of a newbie to this scenario, and I'm remote from both the AP site and the WLC site, though I have full GUI access to the WLC. Is there a decent debugging/faultfinding document that I can use? All the other APs just dropped in and worked, which is great, except I haven't developed my own debug techniques...can I borrow yours???

Suggestions?

Thanks for any help
Jimbo

Probably not a very likely cause, but have you checked that the WLC isn't already supporting the maximum number of APs?

I wish it were that simple....but I have a 250-AP maximum on this WLC, and I'm gradually migrating the estate onto it, and there are only a couple of dozen on so far. Thanks for the thought, though..

Does the PoE switch see the AP in the CDP table? It should also see it in a 'show power inline'.

Best debug you can do when this happens from the WLC CLI

"debug capwap events enable"
"debug capwap details enable"

Depending on your code, replace capwap with lwapp. The debugs will usually give you a good indication as to why a new AP will fail to join a WLC.

HTH
-Derek

Is this AP possibly associating to another WLC on your network? I've seen this happen before despite configuration done beforehand telling it to go to another WLC.

I just went to the WLC it was on and told it where it really should be going.

Dave

I've seen some nasty issues on some APs that were in prior service on a different WLC. Is yours "new" new? I've seen before when a previous WLC address is in there, the AP will still run the discovery state machine--and by all indications it looks like it SHOULD be working, but never even bothers trying to join a WLC that it discovers.

Anyways, this link below ought to serve as a starting point for basic troubleshooting. Having console access to the AP can help too if it's available remotely.

http://www.cisco.com/en/US/products/ps6 ... 8599.shtml

I would make double sure the AP has LWAPP/CAPWAP IOS on it and not autonomous IOS. You never know, could have been shipped a wrong part (ie. wrong IOS), etc. If it is new out of the box, it would show up as "ap" under cdp on the switch, and you can telnet to the IP and log in with "Cisco/Cisco".

OK, armed with all the suggestions, I had a look, and found that the AP wasn't as "new" as I had been lead to believe! I logged on to it, and found that when it booted, it was seen by the adjacent switch via CDP for a while, then started warning about duplicate IP Addresses. Iwas able to log in and get the enable prompt, so I then issued the following commands:

#clear lwap private-config
#clear lwapp ap ip address
#clear lwapp ap hostname
#clear lwapp controller ip address

Once I had done all these, the AP automatically reloaded, and reconfigured from DHCP (with Opt43) It then loaded an image from the WLC, and rebooted again. Finaly, it came up and worked.

Many thanks to all responders, all useful help. I hope I can help you guys out in the future!