DEFINITIONS - 6

enhanced distributed channel access (EDCA): The prioritized carrier sense multiple access with collision
avoidance (CSMA/CA) access mechanism used by quality-of-service (QoS) stations (STAs) in a QoS basic
service set (BSS). This access mechanism is also used by the QoS access point (AP) and operates
concurrently with hybrid coordination function (HCF) controlled channel access (HCCA).
enhanced distributed channel access function (EDCAF): A logical function in a quality-of-service (QoS)
station (STA) that determines, using enhanced distributed channel access (EDCA), when a frame in the
transmit queue with the associated access category (AC) is permitted to be transmitted via the wireless
medium (WM). There is one EDCAF per AC.
extended service area (ESA): The area within which members of an extended service set (ESS) can
communicate. An ESA is larger than or equal to a basic service area (BSA) and might involve several basic
service sets (BSSs) in overlapping, disjointed, or both configurations.
extended service set (ESS): A set of one or more interconnected basic service sets (BSSs) that appears as a
single BSS to the logical link control (LLC) layer at any station (STA) associated with one of those BSSs.
extended service set (ESS) transition: A station (STA) movement from one basic service set (BSS) in one
ESS to another BSS in a different ESS.
fast basic service set (BSS) transition: A station (STA) movement that is from one BSS in one extended
service set (ESS) to another BSS within the same ESS and that minimizes the amount of time that data
connectivity is lost between the STA and the distribution system (DS).
fast basic service set (BSS) transition (FT) 4-Way Handshake: A pairwise key management protocol
used during FT initial mobility domain association. This handshake confirms mutual possession of a
pairwise master key, the PMK-R1, by two parties and distributes a group temporal key (GTK).
fast basic service set (BSS) transition (FT) initial mobility domain association: The first association or
first reassociation procedure within a mobility domain, during which a station (STA) indicates its intention
to use the FT procedures.
fixed station (STA): A STA that is physically attached to a specific location. In licensed bands, a fixed STA
might be authorized to operate only at a specific location.
flexible multicast service (FMS): A service that enables a non-access-point (non-AP) station (STA) to
request a multicast delivery interval longer than the delivery traffic indication map (DTIM) interval for the
purposes of lengthening the period of time a STA can be in a power save state.
flexible multicast stream identifier (FMSID): An identifier assigned by the access point (AP) to a
particular group addressed stream subsequent to a successful FMS Request.
flexible multicast service (FMS) stream: A succession of frames transmitted by the access point (AP) that
correspond to a single flexible multicast stream identifier (FMSID).
flexible multicast service (FMS) stream set: A collection of FMS streams identified by an FMS Token,
used during the FMS Request procedure.
forwarding information: The information maintained by a mesh station (STA) that allows the mesh STA
to perform its path selection and forwarding functions.
fragmentation: The process of segmenting a medium access control (MAC) service data unit (MSDU) or
MAC management protocol data unit (MMPDU) into a sequence of smaller MAC protocol data units

(MPDUs) prior to transmission. The process of recombining a set of fragment MPDUs into an MSDU or
MMPDU is known as defragmentation. These processes are described in 5.8.1.9 of ISO/IEC 7498-1:1994.