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AP in Flexconnect mode not registering automatically to WLC after Link Up



I have 2600 series AP registered with 2504 WLC over WAN working in Flexconnect mode. All of a sudden the AP lost connectivity to WLC and is operational in Flexconnect mode now.

I am concerned whether it should rejoin again automatically ?(which didn't happen) or i need a reboot to get it joined again.


Also if it rejoins automatically does the wireless services go down ? 

Any specific reasons to why it didn't register ? Have debugged capwap and saw error unable to resolve CISCO-CAPWAP-CONTROLLER. Not sure why its unable to resolve now as earlier it was registered this way only.


Any suggestions ??






VIP Purple

If your AP is in "standalone

If your AP is in "standalone mode" & whent the WAN link is up it should go to "connected mode" automatically.

AP won't reboot in this transistion, so you wireless services should not impacted.

What version of software running on your 2504 ? Is this happen to all FlexConnect APs or only to this 2600 ?




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Community Member

Thanks for your response guys

Thanks for your response guys....!


Below are the details :

AP Model no.  AIR-SAP2602I-Z-K9

Software Version7.6.100.0

i could ping CISCO-CAPWAP-CONTROLLER to correct IP address.

Connection from remote site to controller site was also UP.(could ping both end-to-end)

Also tried the capwap ap commands to manually direct to WLC, but didn't work that time.


4 other AP's from different site also disconnected but connected automatically later when connection was up, however for one site(this case) it didn't work. I had to reboot the device and it registered all by itself . But it was strange and i'd expected the AP to join back automatically. 



VIP Purple

Hi Sandeep,Since you are

Hi Sandeep,

Since you are getting wired behaviour, I would suggest you to upgrade your code.

I would suggest you to move onto latest 7.6MR3 code. This is still pre-release status & you can get it via TAC.



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Well there are many option

Well there are many option you could choose to join your LAP to WLC. In your case you are using

DNS to let the LAP knows where the controller is.  All you have to do is check your DNS server and check the entry CISO-CAPWAP-CONTROLLER and also confirm that your DNS is operational when your LAP trying to connect to the controller.

You can also Configure primary controller or master controller to join in LAP via WLC.


Lastly you can also tell the LAP via console the Controller ip ,so that it didn't go through the DNS and name resolution stuff.

Note: you do not need restart you connection still presist. but there are few limitations if your using REAP instaed of H-REAP. But bottom line is that client gets connected on WLC disconnect and  LAP rejoins automatic without restart.

Below is the attached documtation link for troublshooting also.


Hope this helps.


Cisco Employee

When the LAPs discover the

When the LAPs discover the controller, they do not know if the controller is in Layer 2 mode or Layer 3 mode. Therefore, the LAPs always connect to the management interface address of the controller first with a discovery request. The controller then tells the LAP which mode it is in the discovery reply. If the controller is in Layer 3 mode, the discovery reply contains the Layer 3 AP-manager IP address so the LAP can send a join request to the AP-manager interface next.

Note: By default both management and AP-manager interfaces are left untagged on their VLAN during configuration. In case these are tagged, make sure they are tagged to the same VLAN in order to properly receive discovery and join response from the WLC.

The LWAPP AP goes through this process on startup for Layer 3 mode:

  1. The LAP boots and DHCPs an IP address if it was not previously assigned a static IP address.

  2. The LAP sends discovery requests to controllers through the various discovery algorithms and builds a controller list. Essentially, the LAP learns as many management interface addresses for the controller list as possible via:

    1. DHCP option 43 (good for global companies where offices and controllers are on different continents)

    2. DNS entry for cisco-capwap-controller (good for local businesses - can also be used to find where brand new APs join)

      Note: If you use CAPWAP, make sure that there is a DNS entry for cisco-capwap-controller.

    3. Management IP addresses of controllers the LAP remembers previously

    4. A Layer 3 broadcast on the subnet

    5. Over the air provisioning

    6. Statically configured information

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