topic Re: AP Discovery Process in Wireless

AP Discovery Process

Mohamed Adam RHATTAS — Mon, 05 Jul 2021 15:36:49 GMT

Hello All,

I have been having problems with some access points that tend to join the "wrong" WLC through DNS.

I have tried changing the default domain name to prevent that, but even though the query for both "CISCO-CAPWAP/LWAPP-CONTROLLER.false_domain" is not translated (tested through ping from one of the APs), the APs were still joining the wrong controller.

Thus my question; Is disbling the "ip domain-lookup" functionality on the AP influences the discovery process ? If not, is there a way to prevent the AP from resolving the "CISCO-CAPWAP/LWAPP-CONTROLLER" ?

Thank you for your help

Re: AP Discovery Process

Rasika Nayanajith — Wed, 09 May 2018 09:37:52 GMT

Best way to control it using configuring Primary, Secondary, Tertiary controller (High Availability) information on those APs.

Once AP learn about controllers, it will save it in AP's NVRAM, so no matter what you do, it will keep trying those previously learnt WLCs to register. By configuring High Availability, you can predictively register them to a required WLC.

HTH

Rasika

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Re: AP Discovery Process

Mohamed Adam RHATTAS — Wed, 09 May 2018 09:46:21 GMT

Hello Rasika,

Thank you for your response.

I thought so too. But what is strange is that this occure even with the HA Primary controller set. I think that the AP fails to join this one because of some connectivity issue, thus going through the discovery process.

Cheers,

Adam

Re: AP Discovery Process

Mohamed Adam RHATTAS — Fri, 11 May 2018 14:16:17 GMT

Hello again,

I have done a quick lab to check this, and it seems that I was able to influence the discovery process 🙂

So for reference, disabling the domain-lookup on the AP prevents It from sending DNS queries for CISCO-CAPWAP-CONTROLLER.localdomain.

I hope this proves helpful.

Adam

Re: AP Discovery Process

Scott Fella — Fri, 11 May 2018 13:48:57 GMT

Broadcast, DNS and DHCP are discovery process that can’t be changed or let’s say disabled. Like Rasika mentioned, setting the high availability on the AP is the correct way. The hostname is case sensitive also which is important.

So why is an AP still joining another AP, is that controller part of option 43 or on the same subnet as the AP? This can be why the AP’s moved but would only move if connectivity issues occurred in which the AP lost connection to the controller.

Re: AP Discovery Process

Mohamed Adam RHATTAS — Mon, 14 May 2018 11:04:44 GMT

Hello Scott,

Yes, as mentioned in my comment, the APs were having connectivity issues, and when going through the discovery process, these were getting the IP address of a different controller.

--
Adam