Explanation/Reference:
Explanation:
The 802.11r Fast Transition (FT) Roaming is an amendment to the 802.11 IEEE standards. It is a new concept for roaming. The initial handshake with the new Access Point (AP) occurs before client roams to the target AP, called as Fast Transition (FT).
802.11k Assisted Roaming The 802.11k allows 11k capable clients to request a neighbor report containing information about known neighbor APs that are candidates for roaming.
To facilitate roaming, an 11k capable client associated with an AP sends request to a list of neighbor APs.
The request is send in the form of an 802.11 management frame, known as an action frame. The AP responds with a list of neighbor APs on the same WLAN with their Wi-Fi channel numbers. The response is also an action frame. The client identifies the APs candidates for the next roam from the response frame.
The use of 802.11k radio resource management (RRM) process allows the client to roam efficiently and quickly.
To find an AP to roam from the neighbor list information, the 11k capable client does not probe all of the
2.4 GHz and 5 GHz channels. Client does not probe all the channels to reduce channel utilization, thereby, it increases bandwidth on all channels. It reduces roam time and improves the decisions taken by the client. Additionally, it increases battery life of the device as it neither changes the radio configuration for each channel nor sends probe requests on each channel. It avoids the device to process all the probe response frames.
Assisted Roaming with 802.11kThe 802.11k standard allows clients to request neighbor reports containing information about known neighbor APs that are candidates for a service set transition. The use of the
802.11k neighbor list can limit the need for active and passive scanning.
The assisted roaming feature is based on an intelligent and client optimized neighbor list. The 802.11k neighbor list is generated dynamically on-demand and is not maintained on the controller. Two clients on the same controller but different APs can have different neighbor lists delivered depending on their individual relationship with the surrounding APs.
By default, the neighbor list contains only neighbors in the same band with which the client is associated.
However, the dual-list configuration allows 802.11k to return neighbors in both bands.
Reference:
http://www.cisco.com/c/en/us/td/docs/wireless/controller/8-1/Enterprise-Mobility-8-1-Design-Guide/ Enterprise_Mobility_8-1_Deployment_Guide/Chapter-11.html