WLAN_BSS_ENTRY structure (wlanapi.h)

Article
06/24/2021

The WLAN_BSS_ENTRY structure contains information about a basic service set (BSS).

Syntax

typedef struct _WLAN_BSS_ENTRY {
  DOT11_SSID        dot11Ssid;
  ULONG             uPhyId;
  DOT11_MAC_ADDRESS dot11Bssid;
  DOT11_BSS_TYPE    dot11BssType;
  DOT11_PHY_TYPE    dot11BssPhyType;
  LONG              lRssi;
  ULONG             uLinkQuality;
  BOOLEAN           bInRegDomain;
  USHORT            usBeaconPeriod;
  ULONGLONG         ullTimestamp;
  ULONGLONG         ullHostTimestamp;
  USHORT            usCapabilityInformation;
  ULONG             ulChCenterFrequency;
  WLAN_RATE_SET     wlanRateSet;
  ULONG             ulIeOffset;
  ULONG             ulIeSize;
} WLAN_BSS_ENTRY, *PWLAN_BSS_ENTRY;

Members

dot11Ssid

The SSID of the access point (AP) or peer station associated with the BSS. The data type for this member is a DOT11_SSID structure.

uPhyId

The identifier (ID) of the PHY that the wireless LAN interface used to detect the BSS network.

dot11Bssid

The media access control (MAC) address of the access point for infrastructure BSS networks or the peer station for independent BSS networks (ad hoc networks) that sent the 802.11 Beacon or Probe Response frame received by the wireless LAN interface while scanning. The data type for this member is a DOT11_MAC_ADDRESS structure.

dot11BssType

The BSS network type. The data type for this member is a DOT11_BSS_TYPE enumeration value.

This member can be one of the following values.

Value	Meaning
dot11_BSS_type_infrastructure 1	Specifies an infrastructure BSS network.
dot11_BSS_type_independent 2	Specifies an independent BSS (IBSS) network (an ad hoc network).

dot11BssPhyType

The PHY type for this network. The data type for this member is a DOT11_PHY_TYPE enumeration value.

lRssi

The received signal strength indicator (RSSI) value, in units of decibels referenced to 1.0 milliwatts (dBm), as detected by the wireless LAN interface driver for the AP or peer station.

uLinkQuality

The link quality reported by the wireless LAN interface driver. The link quality value ranges from 0 through 100. A value of 100 specifies the highest link quality.

bInRegDomain

A value that specifies whether the AP or peer station is operating within the regulatory domain as identified by the country/region.

If the wireless LAN interface driver does not support multiple regulatory domains, this member is set to TRUE.

If the 802.11 Beacon or Probe Response frame received from the AP or peer station does not include a Country information element (IE), this member is set to TRUE.

If the 802.11 Beacon or Probe Response frame received from the AP or peer station does include a Country IE, this member is set to FALSE if the value of the Country String subfield does not equal the input country string.

usBeaconPeriod

The value of the Beacon Interval field from the 802.11 Beacon or Probe Response frame received by the wireless LAN interface.

The interval is in 1,024 microsecond time units between target beacon transmission times. This information is retrieved from the beacon packet sent by an access point in an infrastructure BSS network or a probe response from an access point or peer station in response to a wireless LAN client sending a Probe Request.

The IEEE 802.11 standard defines a unit of time as equal to 1,024 microseconds. This unit was defined so that it could be easily implemented in hardware.

ullTimestamp

The value of the Timestamp field from the 802.11 Beacon or Probe Response frame received by the wireless LAN interface.

ullHostTimestamp

The host timestamp value that records when wireless LAN interface received the Beacon or Probe Response frame. This member is a count of 100-nanosecond intervals since January 1, 1601.

For more information, see the NdisGetCurrentSystemTime function documented in the WDK.

usCapabilityInformation

The value of the Capability Information field from the 802.11 Beacon or Probe Response frame received by the wireless LAN interface. This value is a set of bit flags defining the capability.

This member can be one or more of the following values.

Value	Meaning
ESS bit 0	An extended service set. A set of one or more interconnected basic service sets (BSSs) and integrated local area networks (LANs) that appears as a single BSS to the logical link control layer at any station associated with one of those BSSs. An AP set the ESS subfield to 1 and the IBSS subfield to 0 within transmitted Beacon or Probe Response frames. A peer station within an IBSS (ad hoc network) sets the ESS subfield to 0 and the IBSS subfield to 1 in transmitted Beacon or Probe Response frames.
IBSS bit 1	An independent basic service set. A BSS that forms a self-contained network, and in which no access to a distribution system (DS) is available (an ad hoc network). An AP sets the ESS subfield to 1 and the IBSS subfield to 0 within transmitted Beacon or Probe Response frames. A peer station within an IBSS (ad hoc network) sets the ESS subfield to 0 and the IBSS subfield to 1 in transmitted Beacon or Probe Response frames.
CF-Pollable bit 2	A value that indicates if the AP or peer station is pollable.
CF Poll Request bit 3	A value that indicates how the AP or peer station handles poll requests.
Privacy bit 4	A value that indicates if encryption is required for all data frames. An AP sets the Privacy subfield to 1 within transmitted Beacon and Probe Response frames if WEP, WPA, or WPA2 encryption is required for all data type frames exchanged within the BSS. If WEP, WPA, or WPA2 encryption is not required, the Privacy subfield is set to 0. A peer station within and IBSS sets the Privacy subfield to 1 within transmitted Beacon and Probe Response frames if WEP, WPA, or WPA2 encryption is required for all data type frames exchanged within the IBSS. If WEP, WPA, or WPA2 encryption is not required, the Privacy subfield is set to 0.

ulChCenterFrequency

The channel center frequency of the band on which the 802.11 Beacon or Probe Response frame was received. The value of ulChCenterFrequency is in units of kilohertz (kHz).

Note This member is only valid for PHY types that are not frequency-hopping spread spectrum (FHSS).

wlanRateSet

A set of data transfer rates supported by the BSS. The data type for this member is a WLAN_RATE_SET structure.

ulIeOffset

The offset, in bytes, of the information element (IE) data blob from the beginning of the WLAN_BSS_ENTRY structure.

This member points to a buffer that contains variable-length information elements (IEs) from the 802.11 Beacon or Probe Response frames. For each BSS, the IEs are from the last Beacon or Probe Response frame received from that BSS network. If an IE is available in only one frame, the wireless LAN interface driver merges the IE with the other IEs from the last received Beacon or Probe Response frame.

Information elements are defined in the IEEE 802.11 specifications to have a common general format consisting of a 1-byte Element ID field, a 1-byte Length field, and a variable-length element-specific information field. Each information element is assigned a unique Element ID value as defined in this IEEE 802.11 standards. The Length field specifies the number of bytes in the information field.

ulIeSize

The size, in bytes, of the IE data blob in the WLAN_BSS_ENTRY structure.

This is the exact length of the data in the buffer pointed to by ulIeOffset member and does not contain any padding for alignment. The maximum value for the size of the IE data blob is 2,324 bytes.

Remarks

The WlanGetNetworkBssList function retrieves the BSS list of the wireless network or networks on a given interface and returns this information in a WLAN_BSS_LIST structure that contains an array of .WLAN_BSS_ENTRY structures.

When the wireless LAN interface is also operating as a Wireless Hosted Network , the BSS list will contain an entry for the BSS created for the Wireless Hosted Network.

Since the information is returned by the access point for an infrastructure BSS network or by the network peer for an independent BSS network (ad hoc network), the information returned should not be trusted. The ulIeOffset and ulIeSize members in the WLAN_BSS_ENTRY structure should be used to determine the maximum size of the information element data blob in the WLAN_BSS_ENTRY structure, not the data in the information element data blob.

Requirements

Requirement	Value
Minimum supported client	Windows Vista [desktop apps only]
Minimum supported server	Windows Server 2008 [desktop apps only]
Header	wlanapi.h

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WLAN_BSS_ENTRY structure (wlanapi.h)

Syntax

Members

Remarks

Requirements

See also

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