Motorola WiNG 5.5 Reference Manual page 441

7. Define the Key Settings.
Pre-Shared Key
8. Define Key Rotation values.
Unicast messages are addressed to a single device on the network. Broadcast messages are addressed to multiple devices.
When using WPA2, a wireless client can use 2 keys: one unicast key, for its own traffic to and from an access point, and
one broadcast key, the common key for all clients in that subnet.
Motorola Solutions recommends rotating these keys so a potential hacker would not have enough data using a single key
to attack the deployed encryption scheme.
Unicast Rotation Interval
Broadcast Rotation
Interval
Figure 6-5 WLAN Security - WPA/WPA2-TKIP screen
Enter either an alphanumeric string of 8 to 63 ASCII characters or 64 HEX characters as the
primary string both transmitting and receiving authenticators must share. The
alphanumeric string allows character spaces. The access point converts the string to a
numeric value. This passphrase saves the administrator from entering the 256-bit key each
time keys are generated.
Define an interval for unicast key transmission interval from 30 - 86,400 seconds. Some
clients have issues using unicast key rotation, so ensure you know which kind of clients
are impacted before using unicast keys. This feature is disabled by default.
When enabled, the key indices used for encrypting/decrypting broadcast traffic is
alternatively rotated based on the defined interval. Define a broadcast key transmission
interval from 30 - 86,400 seconds. Key rotation enhances the broadcast traffic security on
the WLAN. This feature is disabled by default.
Wireless Configuration 6 - 15