802.11k and 802.11r are both standards designed to create a more seamless roaming experience for wireless clients. This is particularly useful for VoIP or other applications where long roaming times can result in a very noticeable impact on performance.
A wireless client will decide to roam to a new access point (AP) when it detects a better signal from that AP than the one it is currently associated with. This behavior is normal, particularly when devices are moving around within an environment, such as laptops, tablets, and mobile phones.
When a client roams to a new AP it needs to establish an association/authentication relationship with that AP. In situations where the APs are acting independently of each other, this whole process must occur each time the client moves to a new AP. Without the inclusion of standards like 802.11k and 802.11r, the client will disconnect from it's existing AP before connecting to the new one. This results in a period of time where the client has no network access. This can be manifested in the form of packet loss, dropped calls, or other negative performance.
Both standards take different measures to reduce the time required for a client to roam between APs in the same network, and thus reduce the impact of roaming on performance.
This feature can be enabled from the Configure > Access control page under Network access > 802.11r. If this option does not appear, a firmware update may be required.
Note: 802.11r is intended for use on SSIDs that use enterprise authentication methods.
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