Motorola AP-7131 Product Reference Manual page 203

Defining Primary WLANs allows an administrator to dedicate BSSIDs (4 BSSIDs are
available for mapping) to WLANs. From that initial BSSID assignment, Primary WLANs can
be defined from within the WLANs assigned to BSSID groups 1 through 4. Each BSSID
beacons only on the primary WLAN.
The user should assign each WLAN to its own BSSID. In cases where more than four WLANs
are required, WLANs should be grouped according to their security policies so all of the
WLANs on a BSSID have the same security policy. It is generally a bad idea to have WLANs
with different security policies on the same BSSID, as this will result in warning or error
messages.
NOTE If using a single-radio access point, there are 4 BSSIDs available. If using
a dual-radio access point, 4 BSSIDs for the 802.11b/g/n radio and 4
BSSIDs for the 802.11a/n radio are available.
Network Management 5-65