802.11r Handoffs Failing: 802.11r Key Cache look up failed in (re)-assoc req

[#1]

I am trying to set up a wireless LAN using two Cisco 3602i APs on a Virtual WLC running software version 8.2.160.0. My goal is to have an iPhone 6s client using Voice-over-WiFi be able to fast-roam between these two APs using 802.11r/802.11k/802.11v without dropping the voice call.

As far as I can tell, I have set everything up for this according to Cisco and Apple recommendations, but the handoffs continually fail. Running 'debug client <iphone-mac-address>' on the controller produces the following message when the handoff attempts fail:

Association Failed on REAP AP BSSID 44:ad:d9:8e:8b:fe (slot 1), status 11 0 802.11r Key Cache look up failed in (re)-assoc req

Unfortunately, a Google search for "key cache look up failed" returns only one result - an un-annotated pastebin dump.

Here is the vWLC configuration for the WLAN in question, id '2', SSID 'phone-test-5g':

https://pastebin.com/DaSqp5cT

And here is the complete output of a 'debug client ' capturing a failed roam/handoff event:

https://pastebin.com/sENSsnpA

I have tried a fairly wide variety of configurations but have not been able to get this to work using any combination of settings. If anyone has any suggestions, I will greatly appreciate hearing them.

[robvreedepvh]

Yes, we did fix the 802.11r issue by placing the FlexConnect AP’s in flexconnect groups (this is different from AP groups).

After placing them in the flexconnect groups, 802.11r FT started working.

Note: there are some limitations to the number of AP’s in a flexconnect group, differs per WLC model.

our model (5520) supports 100 AP’s in one flexconnect group.

The 5508 supports 25 in one group. If you have more, create multiple flexconnect groups (i.e. per floor or 2 floors).

Hope this helps, please reply if it does.

Thanks,

Rob