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Question on AP join priority

hi Guys,

I am having a bit of trouble getting AP register to an expected WLC. basically I have two WLCs in the network, one with IP address and the other one with IP

I have configured DHCP pool for APs on a 3560 switch, and configured DHCP option 43 as below:


     option 43 hex f108.c0a8.142d.c0a8.0e5a      

so I have c0a8142d ( in the front, and my understanding is that this will make the APs to join first, and only on join failure, the AP will start to join

however based on my test results, it seems two APs (3500) always joining after learnt the WLC ip address (each time I run the test, I did clear the AP configuration from the WLC to set the AP back to factory default). even from the AP console, it shows is obtained first:


*Mar 16 10:58:47.993: %CAPWAP-5-DHCP_OPTION_43: Controller address obtained through DHCP
*Mar 16 10:58:47.993: %CAPWAP-5-DHCP_OPTION_43: Controller address obtained through DHCP

Translating "CISCO-LWAPP-CONTROLLER"...domain server (

wmmAC status is FALSE
*Jun 12 13:51:14.000: %CAPWAP-5-DTLSREQSEND: DTLS connection request sent peer_ip: peer_port: 5246
*Jun 12 13:51:14.001: %CAPWAP-5-CHANGED: CAPWAP changed state to 
*Jun 12 13:51:15.499: %CAPWAP-5-DTLSREQSUCC: DTLS connection created sucessfully peer_ip: peer_port: 5246
*Jun 12 13:51:15.501: %CAPWAP-5-SENDJOIN: sending Join Request to
*Jun 12 13:51:15.501: %CAPWAP-5-CHANGED: CAPWAP changed state to JOIN
*Jun 12 13:51:15.680: %CAPWAP-5-CHANGED: CAPWAP changed state to CFG
*Jun 12 13:51:15.806: %CAPWAP-5-CHANGED: CAPWAP changed state to UP


I have tried to change the order of WLC address in option 43 configuration, however this did not make any change.

From the WLC GUI on, fro statistics --> AP join, I could see a record of the AP trying to join this WLC first, but currently showing "disconnected" with the last AP disconnect reason as "AP found primary WLC in primary discovery response".

anyone has seen this issue before and could you please advise if there is any other test I could try?

thanks in advance for your help.



Re: Question on AP join priority

Option 43 tells the AP of 1 or more WLC that are in the network. When the AP sends its discovery request, it learns of all the WLC that are configured in the same mobility group as the WLC. This message also has the WLC max AP count as well as the excess availability. The AP should join the WLC that has the greatest excess availability.

Now if you want to force your AP to join a specific WLC so that you know where to look to configure them, you should set that WLC to have Master Controller Mode to on. This will force any AP that does not have configured primary secondary tertiary to join it.


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HTH, Steve ------------------------------------------------------------------------------------------------ Please remember to rate useful posts, and mark questions as answered