Mobility Groups WLC

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Nov 21st, 2008
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Trying to configure the Primary Controller Name on my WLC for the Mobility Group.

I am wondering what anme to put in there. I would like to put the ip address but it says not too. does the system name need to be in DNS?? I do not see how it can find it if it is not, but it does not say anything about how it is to work.

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jeff.kish Fri, 11/21/2008 - 14:33
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Do you mean that you're entering the Primary Controller name for an AP? Mobility group WLCs require IP and MAC addresses to add.

Regardless of whether APs have stored Primary, Secondary, and Tertiary controllers, they perform their full start-up search for controllers. Using broadcast, OTAP, DNS, and DHCP option 43, they form a list of all controllers available.

After forming their list, they send LWAPP DISCOVERY messages to each controller, which responds with their hostname and their remaining AP capacity. The AP then selects its primary, secondary, or tertiary controller if those are configured. If they are not, they choose the controller with the greatest capacity.

So to answer your question, you enter the name of the controller :)

wesleyterry Fri, 11/21/2008 - 21:14
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To elaborate a little more, the Access Points only use DNS to resolve an entry for the name "CISCO-LWAPP-CONTROLLER"

Whether or not your controller names are in DNS is irrelevent to this process.

So, when entering primary/secondary/tertiary controllers for an Access Point, do not use a fully qualified domain name (controllername . company . com). Only use controllername. This assumes you are even using DNS for the discovery. As Jeff mentions, broadcasts and DHCP option 43 are alternate ways for the AP to find an initial controller.

dilip.kulkarni Tue, 03/17/2009 - 22:19
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When you say "After forming their list, they send LWAPP DISCOVERY messages to each controller", does the AP send a Unicast IP packet to each controller?

We cannot see any packets other than IP Broadcasts from the AP even though the DHCP Option 43. What could be the reason for this?

Another question: How does the AP correlate the IP address in the Option 43 list to the name of the controller?

Leo Laohoo Tue, 03/17/2009 - 22:50
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Have you browsed this document yet?

DHCP OPTION 43 for Lightweight Cisco Aironet Access Points Configuration Example


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