Understanding Key Refresh
You can enable broadcast and session key rotation intervals on a per virtual access point basis. These parameters only apply to security modes that involve key rotation (dynamic WEP and WPA Enterprise).
The broadcast key refresh rate sets the interval at which the broadcast (group) key is refreshed for clients associated to a particular virtual access point. The session key refresh rate specifies the interval at which the access point refreshes session (unicast) keys for each client associated to a particular virtual access point. Each of these rotations can be disabled by setting the interval to zero. The broadcast key refresh timer is started when the access point is configured. This timer expires after every key refresh interval. A client that associates during this interval will get its first broadcast key refresh the next time this timer expires. From the client’s perspective, this first refresh will most likely occur before the full refresh rate interval.
