Replay detection

4.5.4.7 Replay detection

The replay detection mechanism defines a means by which a STA that receives a data or protected Robust
Management frame from another STA can detect whether the received frame is an unauthorized
retransmission. This replay protection mechanism is provided for data frames for STAs that use enhanced
data cryptographic encapsulation mechanisms. The replay protection mechanism is also provided for robust
management frames for STAs that use CCMP and Broadcast/Multicast Integrity Protocol (BIP).
4.5.4.8 Fast BSS transition
The FT mechanism defines a means for a STA to set up security and QoS parameters prior to reassociation
to a new AP. This mechanism allows time-consuming operations to be removed from the time-critical
reassociation process.
4.5.4.9 Robust management frame protection
Robust management frames are a set of management frames that can be protected by the management frame
protection service. The robust management frames are Disassociation, Deauthentication, and robust Action
frames. Action frames specified with “No” in the “Robust” column of Table 8-38 are not robust
management frames and are not protected.
Management frame protection protocols in an infrastructure BSS or IBSS apply to robust management
frames after RSNA PTK establishment for protection of individually addressed frames is completed and
after delivery of the IGTK to protect group addressed frames. Robust management frame protection is
implemented by CCMP, BIP, and the SA Query procedure.
Management frame protection protocols in an MBSS apply to individually addressed frames after
establishment of the RSNA MTK, and to group addressed frames indicated as "Group Addressed Privacy" in
Table 8-38. Robust management frame protection is implemented by CCMP.
4.5.5 Spectrum management services
4.5.5.1 General
Two services are required to satisfy requirements in some regulatory domains (see Annex D and Annex E)
for operation in the 5 GHz band. These services are called transmit power control (TPC) and dynamic
frequency selection (DFS).
4.5.5.2 TPC
Radio regulations may require radio local area networks (RLANs) operating in the 5 GHz band to use
transmitter power control, involving specification of a regulatory maximum transmit power and a mitigation
requirement for each allowed channel, to reduce interference with satellite services. The TPC service is used
to satisfy this regulatory requirement.

The TPC service provides for the following:
— Association of STAs with an AP in a BSS based on the STAs’ power capability.
— Specification of regulatory and local maximum transmit power levels for the current channel.
— Selection of a transmit power for each transmission in a channel within constraints imposed by
regulatory requirements.
— Adaptation of transmit power based on a range of information, including path loss and link margin
estimates.