Chapter 6 Deploying Wireless Networks for FortiOS 5.0 : Wireless network monitoring : Monitoring rogue APs : Rogue AP scanning as a background activity
  
Rogue AP scanning as a background activity
Each WiFi radio can perform monitoring of radio channels in its operating band while acting as an AP. It does this by briefly switching from AP to monitoring mode. By default, a scan period starts every 300 seconds. Each second a different channel is monitored for 20ms until all channels have been checked.
During heavy AP traffic, it is possible for background scanning to cause lost packets when the radio switches to monitoring. To reduce the probability of lost packets, you can set the CLI ap-bgscan-idle field to delay the switch to monitoring until the AP has been idle for a specified period. This means that heavy AP traffic may slow background scanning.
The following CLI example configures default background rogue scanning operation except that it sets ap-bgscan-idle to require 100ms of AP inactivity before scanning the next channel.
config wireless-controller wtp-profile
edit ourprofile
config radio-1
set ap-bgscan enable
set rogue-scan enable
set ap-bgscan-period 300
set ap-bgscan-intv 1
set ap-bgscan-duration 20
set ap-bgscan-idle 100
end
end