User's Guide

Anomalous Behavior Alarms (ABA) feature is only available for AirDefense Enterprise servers and does
not require any specific license. This feature is enabled when you enable Performance Profile. ABA is
calculated for sanctioned clients and BSS only. All other data is ignored.
The AirDefense server flags trac behavior that deviates significantly from observed normal behavior.
The server learns specific attributes of trac monitored over a configurable period of time. It uses this
information to flag any trac that deviates significantly from its learned trac behavior.
AirDefense ABA works in two phases.
• Background Learning Phase
• Live Data Threshold Comparison Phase
These phases are common to all alarms based on the anomaly detection paradigm. Each alarm type
could have dierent learning parameters and custom threshold computation methods.
In the Background Learning Phase, the AirDefense server monitors the forensic data in the data
store for a configured duration of time. It then computes a baseline behavior against which an event will
be tested. The learning phase training window is sliding to enable including the live data being added to
the forensic store. ABA learning happens at regular intervals during the day to compute thresholds for
all anomalous alarms. The default learning interval for each alarm is 14 days. Thresholds are computed
and stored in 5 minute windows. These learning interval configuration values cannot be modified. These
thresholds are computed on the scope where performance profile is enabled. The scopes can be at
Site Level, Floor Level, or System Level.
In the Live Data Threshold Comparison Phase, live data from the sensors is compared with
the computed thresholds for the enabled scope. If the live data is above the computed threshold, its
corresponding alarm is triggered. For example, if, in the live data, the total AP Management Frames
in a location in a 5 minute interval exceeds the computed threshold value of the total AP Management
Frames in the same 5 minute interval over the last 14 days, then the AP Management Frame
Anomalous Behavior Frames alarm is raised.
ABA computation starts at 00:00 hour. The computed threshold values are not persistent across server
reboots and restarts. In case a server is restarted or rebooted, threshold computation will commence at
00:00 hours. You will not have computed threshold value from the time the server was rebooted or
restarted till the nearest 00:00 hour.
The following Anomalous Behavior Alarms are supported
• MU Management Frame Anomalous Behavior Frames
• MU Data Frame Anomalous Behavior Frames
• MU Control Frame Anomalous Behavior Frames
• AP Management Frame Anomalous Behavior Frames
• AP Data Frame Anomalous Behavior Frames
• AP Control Frame Anomalous Behavior Frames
• MU Management Frame Anomalous Behavior Bytes
• MU Data Frame Anomalous Behavior Bytes
• MU Control Frame Anomalous Behavior Bytes
• AP Management Frame Anomalous Behavior Bytes
Configuration
Tab Anomaly Baseline View
Extreme AirDefense User Guide for version 10.5. 561