FlexConnect AP Deployment- Clients having issues with DHCP

[awatson20]

I have 7 2602I access points deployed and operating in FlexConnect.  We are doing both local switching and local authentication.  These AP's are in a FlexConnect Group with local Radius server defined as the primary server in the Flex Group.  This has been working for a few days.  The vlan these users are getting DHCP is local and there is a local DHCP server.  There is also a backup DHCP server at the central site. 

We are beginning to get reports of users having problems connecitng to wireless.  Authentications asre successful, but when I look at the WLC, I notice they are not getting an IP address.  They either show 0.0.0.0, or the default address 169.254.12.2.  Some are connecting, and some do not.  This issue is very intermittent.  I will also add, this location does have periods of high latency, hence the reason we are doing local switching/local auth.  This client eventually got an IP address, but it took a while.

We never had any issues unitl we deployed in Flex mode.  I could switch these Ap's back to local mode(central switch/central auth) and this problem would never occur.  Any ideas? Thanks.

[David Watkins]

If you are locally switching traffic, then the WLC will not learn the IP address of the client.  There are enhancement requests to improve the types of client information reported to the WLC, even when the clients are locally authenticating/switching, but I've seen mixed results with what client information actually shows up.

If you have problems with clients getting an IP on particular WLANs (or particular VLANs of the switch the AP is connected to in this case), and authentications are not a problem, I would simply take a wired client and put them on the respective VLANs to troubleshoot.

[awatson20]

I agree that in local auth mode the WLC does not learn as much info, but if you check learn IP address under the WLAN it will learn it and can be seen from monitor clients.

Although authentications are successful, I have not ruled out some sort of local auth issue.

One other thing to note, we got a debug client and the first dhcp request went to the local dhcp server, then a request to the backup dhcp at HQ. however the dhcp request was fulfilled by the local dhcp server. The local server appears to be working correctly, and there are plenty of addresses available.

Sent from Cisco Technical Support iPhone App

[awatson20]

I do not have any type of vlan support configuration enabled for these access points on the WLC. Could that be related?

Sent from Cisco Technical Support iPhone App