How to avoid new APs from joining wrong controller

[steiostb1]

We are slowly migrating from old APs (AIR-3502) to new ones (C9120). Since the old AIR-3502 APs will not run on the same software as the C9120 (8.10.131.0), we will have to setup a new WLC with 8.5.161.0. Both WLC are in same mobility group to utilize roaming and RF-data. DHCP option 43 is used to send correct AP to the correct WLC, but when the WLC are in the same mobility group, I fear that new APs are trying to connect to the WLC with the old software (WLC with lowest load). Setting primary controller will only solve this issue for APs that are connect, not new APs that have never been connected before.

Is there a way to avoid new APs from joining the WLC with the old unsupported software?

[Leo Laohoo · Accepted solution]

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@steiostb1 wrote:

Since the old AIR-3502 APs will not run on the same software as the C9120 (8.10.131.0),

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This is the answer to your question.  3502 will never be able to join a controller running 8.6.X.X and newer.  Right? 

On the flip side, Catalyst 91XX will never join a controller not running 8.10.X.X. 

So set your DHCP Option 43 like this:  

• Primary controller will be WLC running 8.10.X.X;
• Secondary controller will be WLC running 8.5.X.X (and older).

[steiostb1]

Thank you for replying.

I feared that the C9120 would try to join the wlc running 8.5.161.0, and just be somehow stuck there. But if that is not the case, there should be no issue.

[Sandeep Choudhary]

As leo siad...

9120 AP need minimum 8.10.105.0 version on WLC to join.

Regards

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[Scott Fella]

Do you have ac modules on your 3502’s? Since you stated that you are migrating to 9120’s, you should consider that client devices might tend to prefer ac or ax over 802.11n causing coverage issues. This might be a problem until you fully replace all your older access points.