802.11k (Neighbor reports) is not mentioned in either the data sheet for the 8821 phone or the current revision of the 8821 deployment guide. Do the phones support this and/or should this feature be enabled on the VoWLAN ESS to optimize performance of the 8821's when roaming in conjunction with 802.11r?
I wanted to provide an answer to this from the 8821 Data Sheet & Deployment Guides as I've seen this question come up frequently in TAC Cases and hope to spare those the time to link to documentation. Below you'll find the stance on 801.11r/802.11k/802.11v and how the 8821 does and doesn't support these protocols:
In addition, roaming between access points within the campus will support more seamless voice communications with the 8821’s support of Fast Transition (802.11r). This protocol was specifically designed for mobile Voice over IP (VoIP) communications devices within Wi-Fi networks. Bluetooth is supported for the user’s choice of third-party wireless headsets and adds freedom by untethering the user from the handset.
Fast Roaming It is recommended to utilize 802.11r / Fast Transition (FT)for fast roaming. Enabling 802.11r (FT) also reduces the number of frames in the handshake when roaming to only two frames. Reducing the number of frames during a roam, increases the chances of roam success.