The 802.11 station uses a key-mapping key for cipher operations on all sent or received packets for which a mapping exists for the receiver's media access control (MAC) address (RA) or the transmitter's MAC address (TA). For received packets, the 802.11 station uses the TA as the index within the key-mapping key table. For transmitted packets, the station uses the RA as the index. The 802.11 station uses a single key for each RA/TA mapping.
It is recommended that the 802.11 station support a key mapping table that stores a minimum of 32 keys. If the miniport driver supports the Extensible Station (ExtSTA) mode, the 802.11 station can support a key-mapping table size of 32 or greater.
The miniport driver, when operating in ExtSTA mode, reports the size of the 802.11 station's key-mapping key table when OID_DOT11_EXTSTA_CAPABILITY is queried.
For more information about the usage of key-mapping keys, refer to Clause 188.8.131.52 of the IEEE 802.11-2012 standard.