WLAN not available after break in connectivity between AP and WLC

Unanswered Question

I have a strange issue with our wireless infrastructure.  We are using AP 124AG with 4404 controller.  We have multiple SSID ready to deploy, but due to issues with NAC we are currently only using an SSID with wireless guest access.  This network is not using HREP, so is tunneling back to the controller.  The controller has a DHCP scope and issues IP addresses to this network.  If a break in IP connectivity occurs between the controller and the AP then the wireless network is still visible, but can't get DHCP addresses.  If I recycle the APs then connectivity returns.  Has anyone else seen an issue like this before?  Our Cisco support is mainly managed by our suppliers, but if anyone has seen this before I would be grateful to hear your comments.

If you want firmware numbers or more information then let me know, as any help is appreciated.



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LCC Data Networks Fri, 12/04/2009 - 07:32
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The APs should automatically re-discover a WLC when it comes back online, in fact, they spend all their downtime attempting to do this.  How do your APs originally learn about the Controller?  DNS, Op43 DHCP or are they primed to an IP of the controller?

I tend to see access points return to the controller within a few minutes of a reboot, without any intervention such as powercycling the access points or bumping switchports.

I recommend checking the version of software on the WLC is the latest you can support.  It sounds like you have quite a new installation, and it might be worth resetting the WLC to defaults if you can't pin the issue down.

Thanks for the reply Stuart.  The APs use option 43.  It is starting to look like this is a DHCP issue as much as an AP issue.  I was running the DHCP scope on the WLC, but since moving DHCP to a device external to the WLC then is seems to be staying up.  It's strange.  Maybe just can't trust DHCP on WLC when using tunneled mode.


Leo Laohoo Fri, 12/04/2009 - 23:05
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Depending on the firmware of the WLC, have tried to configure the primary/secondary controllers?  In version 4.x, you will need to use CLI and on 5.X and 6.X this can be done usine GUI.


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