AP not joining with correct wlc

[palani2010]

• Issue - when AP connects to the network but it is registering with wlc A and downloading the image and after downloading it is registering with correct controller i.e., WLC B which is nearby DC

[Scott Fella]

You need to define the primary controller/ip so that the ap knows which one to use.  I don't know what equipment you have, nor is your want to use wlc A or wlc b?  Either way, however you are doing the discovery, either DNS or DHCP, you can define that there, or you can console to each ap and define that there also. There are a lot of information out there on ap discovery and setting the ap primary controller.  https://community.cisco.com/t5/wireless-mobility-knowledge-base/lightweight-ap-discovery-process-for-wireless-lan-controllers/ta-p/3128151

[Mark Elsen]

   - Don't understand your question , please explain better ,

 M.

[palani2010]

I have two dc centralized wlc 9800 and branch location installing new AP and it is registering with one of wlc(WLC-A) and trying to download the image. Post downloading the image it got registered with different controller (WLC-B). 

My question why this is happens. Why can't register with wlc (WLC-B) directly and AP can download the image ?

[Scott Fella]

You need to look at the links I posted on setting up either DNS or DHCP to point the ap to a specific controller.  What is happening, its finding both and each controller is providing a status or how many ap's and client's it has and the ap is choosing the one with the lowest resource.  No matter what, even after the join when it has the image, you need to define the primary and secondary controller info.

[Leo Laohoo · Accepted solution]

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@palani2010 wrote:
Why can't register with wlc (WLC-B) directly and AP can download the image ?

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There are many reasons why an AP can download the image from one controller and then join another controller.

And one of the reason is WLC "health" (CPU and memory utilization, uptime, WNCD health).   There are several ways around this: 

1.  Configure DHCP Option 43 to point to only one WLC; 

2.  Configure DHCP Option 43 to point to a "landing" controller.  This controller, in a N+1 scenario, usually have 0 APs.  

[Scott Fella]

Here is another doc you can review, like what @Mark Elsen mentioned, you question is not clear on what you are expecting or what you want accomplished.

https://ipcisco.com/lesson/access-point-discovery-and-join-process/

[Flavio Miranda · Accepted solution]

@palani2010 

If you have more than one WLC available you need to manage this. You can turn one WLC to be a master WLC. This way AP will prefer that WLC and from there, you can distribute the AP to whatever WLC you desire.

 You can also use DHCP and DNS to support on the AP decision.