Explanation/Reference:
Explanation: Client MFP shields authenticated clients from spoofed frames, which prevents the effectiveness of many of the common attacks against wireless LANs. Most attacks, such as deauthentication attacks, revert to simply degraded performance when they contend with valid clients.
Specifically, client MFP encrypts management frames sent between access points and CCXv5 clients so that both access points and clients can take preventive action and drop spoofed class 3 management frames (that is, management frames passed between an access point and a client that is authenticated and associated). Client MFP leverages the security mechanisms defined by IEEE 802.11i to protect these types of class 3 unicast management frames: disassociation, deauthentication, and QoS (WMM) action.
Client MFP can protect a client-access point session from the most common type of denial-of-service attack. It protects class 3 management frames with the same encryption method used for the data frames of the session. If a frame received by the access point or client fails decryption, it is dropped, and the event is reported to the controller.
In order to use client MFP, clients must support CCXv5 MFP and must negotiate WPA2 with either TKIP or AES-CCMP. EAP or PSK can be used to obtain the PMK. CCKM and controller mobility management are used to distribute session keys between access points or Layer 2 and Layer 3 fast roaming.
Reference: http://www.cisco.com/c/en/us/support/docs/wireless-mobility/wlan-security/82196-mfp.html