Behaviour of WLC with too many LAP's?

[bonedaddy76]

     I am a bit new to the Cisco WLC and we recently inherited support for a property with no information and we believe they may have more LAP's on the network than the controller is authorized for (an AIR-WLC4402-50-K9). I was wondering what I can do to find out of this is the case? I can tell you that CDP is not going to help here because many of the LAP's are attached to devices that won't pass CDP packets to the core.

I am bit curious also as to the behavior of the controller. Does it just adopt the first 50 LAP's and then will not adopt any more even if all the LAP's that were originally adopted are not online? Or if one of the LAP's that was there goes offline, will it pick up an adopt one that is not adopted (say, in the case there are 51 LAP's on the network)? Do old LAP's need to be "deleted" somehow to take on new ones?

Thank in advance for any help on this matter.

[Scott Fella]

The WLC you have will only support 50 AP's at a given time.  Depending on what code you are running, I believe the 6.0 had this feature, but the 7.0 for sure.  You can give an access point higher priority. 

http://www.cisco.com/en/US/docs/wireless/controller/7.0/configuration/guide/c70lwap.html#wp1335366

[bonedaddy76]

Scott, thanks for the input. I am aware that controller can only handle 50, I am just not sure what happens when you connect more than 50 to the network or if its possible to determine this from the WLC. I am seeing the following in the traps also:

Failed to authorize AP with Base Radio MAC 00:0f:f7:f7:16:dc.  Authorization entry does not exist in Controller's AP Authorization  List.

Not sure if it has anything to do with the issue, but the site is complaining of the wireless going up and down.

[Scott Fella]

Well set the priority if youare running the correct code, or else shut down the AP's that you don't need.  The only other way is to get another WLC.

[Leo Laohoo]

Scott, thanks for the input. I am aware that controller can only handle 50, I am just not sure what happens when you connect more than 50 to the network or if its possible to determine this from the WLC.

If you have more than 50 attempting to go to a WLC-4402-50 then the first 50 will join.  The 51st and the rest won't.

Which first 50 is determined on a first-come-first-serve-until-full basis.

As what Scott said, you can force it by configuring the "priority" level.  Default is "low". 

[bonedaddy76]

OK, so say I have 51 LAP's visible to the controller and 50 are joined and one is in "space", then one of the 50 is disconnected or goes offline, will the 51st LAP then join the controller? And at that point, assuming no priority is set, if the one that was offline comes back, it is now the one in "space", correct?

[Scott Fella]

That is correct... but you still can have some unusual behavior and that is what you need to watch.  If you click on the wireless tab on the gui, look at the last ap, that is the last ap that joined.  If you see that the last few keep bouncing per say, then remove an AP so that you only have 50.

[Leo Laohoo]

Yes.  This is correct. 

[bonedaddy76]

Thanks for the help, I think I know everything I need now.