DEFINITIONS - 19

unreachable destination: A destination mesh station (STA) for which the link to the next hop of the mesh
path to this destination mesh STA is no longer usable.
unreachable star: A star that cannot be reached. Often associated with impossible dreams.
unscheduled service period (SP): The period that is started when a quality-of-service (QoS) station (STA)
transmits a trigger frame to the QoS access point (AP).
uplink: A unidirectional link from a non-access-point (non-AP) station (STA) to an access point (AP).
user priority (UP): A value associated with an medium access control (MAC) service data unit (MSDU)
that indicates how the MSDU is to be handled. The UP is assigned to an MSDU in the layers above the
MAC.
validated AP: An AP that has either been explicitly configured as a Neighbor or learned through a
mechanism like the Beacon Report.
wildcard BSSID: A BSSID value (all binary 1s) used to represent all BSSIDs.
wildcard SSID: A SSID value (null) used to represent all SSIDs.
wireless distribution system (WDS): Often used as a vernacular term for a mechanism for wireless
communication among nonmesh stations (STAs) using a four address frame format.
NOTE—This standard specifies such a frame format and its use only for a mesh basic service set (MBSS). Because of
this, the term WDS is obsolete and subject to removal in a subsequent revision of this standard.
wireless local area network (WLAN) system: A system that includes the distribution system (DS), access
points (APs), and portal entities. It is also the logical location of distribution and integration service
functions of an extended service set (ESS). A WLAN system contains one or more APs and zero or more
portals in addition to the DS.
wireless medium (WM): The medium used to implement the transfer of protocol data units (PDUs)
between peer physical layer (PHY) entities of a wireless local area network (LAN).
3.2 Definitions specific to IEEE 802.11
The following terms and definitions are specific to terms or references in this standard and are not appropriate
for inclusion in the IEEE Standards Dictionary: Glossary of Terms & Definitions.
20 MHz basic service set (BSS): A BSS in which the Secondary Channel Offset field is equal to SCN.
20 MHz high-throughput (HT): A Clause 20 transmission using FORMAT=HT_MF or HT_GF and
CH_BANDWIDTH=HT_CBW20.
20 MHz mask physical layer convergence procedure (PLCP) protocol data unit (PPDU): A Clause 18
PPDU, a Clause 19 orthogonal frequency division multiplexing (OFDM) PPDU, or a Clause 20 20 MHz
high-throughput (HT) PPDU with the TXVECTOR parameter CH_BANDWIDTH equal to HT_CBW20
and the CH_OFFSET parameter equal to CH_OFF_20. The PPDU is transmitted using a 20 MHz transmit
spectral mask defined in Clause 18, Clause 19, or Clause 20, respectively.
20 MHz physical layer convergence procedure (PLCP) protocol data unit (PPDU): A Clause 16 PPDU,
Clause 18 PPDU, Clause 17 PPDU, Clause 19 orthogonal frequency division multiplexing (OFDM) PPDU,
or Clause 20 20 MHz high-throughput (HT) PPDU with the TXVECTOR parameter CH_BANDWIDTH
equal to HT_CBW20