Wireless Deauthentication Rate
Possible reasons for the event:
At sites where it is common to configure the driver to use a primary and secondary AP, a high number of authentications can indicated intermittent signal problems between a station and its primary AP. When the signal from the primary AP falls beneath a certain threshold, the station authenticates with the secondary AP. When a strong signal is again sensed from the primary AP, the station will deauthenticate with the secondary AP before re-authenticating with the primary AP. Such intermittent signal problems can be resolved by getting a better antenna for the AP, relocating the AP, or eliminating sources of RF interference between the AP and its stations (cordless phones, microwaves, etc.)
"Roaming" stations can cause a similar pattern of deauthentications as described in a).