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802.11 Network Configuration

  • Articolo

In the 802.11 specification, an 802.11 network is referred to as a basic service set (BSS). A BSS is made up of two or more stations (STAs) that communicate with each other. Individual BSS networks are established through a unique service set identifier (SSID). There are two types of BSS networks:

  • Ad hoc
    An ad hoc network consists of two or more mobile stations that communicate with each other directly. Ad hoc networks are referred to as independent basic service sets(IBSSs) within the 802.11 specification.

  • Infrastructure
    An infrastructure network consists of one or more mobile stations that communicate with each other through an access point (AP). In this type of BSS, the AP itself is considered a STA. An infrastructure network that consists of multiple APs within the same BSS is referred to as an extended service set(ESS) within the 802.11 specification.

    Each AP within the same BSS must be assigned the same SSID. After a mobile station is assigned an SSID of the BSS to associate with, it can choose any AP within the ESS. After it is associated, the mobile station can also decide to roam to other APs within the ESS.

An 802.11 miniport driver will periodically be requested by the operating system to scan for all BSS networks that can be accessed. For more information about this process, see Scanning 802.11 Networks.

The following OIDs are used to initiate scans and return the list of visible BSS networks:

  • OID_802_11_BSSID_LIST_SCAN

    This OID is set to initiate a BSS scan. The 802.11 device scans for BSS networks across all channels that it supports.

  • OID_802_11_BSSID_LIST

    This OID is queried to obtain the results of the BSS scan. A query of this OID occurs within six seconds after OID_802_11_BSSID_LIST_SCAN is set. A query of this OID can also occur without a prior setting of OID_802_11_BSSID_LIST_SCAN.

Before the 802.11 device can associate to a BSS network, the device must be configured to operate within the BSS. The following OIDs set or query the BSS network parameters used by the 802.11 device:

  • OID_802_11_INFRASTRUCTURE_MODE

    This OID queries or sets the network mode the device is using for 802.11 associations. Setting this OID configures the device for operating within infrastructure or ad hoc networks.

  • OID_802_11_AUTHENTICATION_MODE

    This OID queries or sets the 802.11 authentication mode that the device uses when associating. For more information about the various 802.11 authentication modes, see 802.11 Authentication.

  • OID_802_11_ENCRYPTION_STATUS

    This OID queries or sets the encryption mode on the device. For the WPA and WPA2 authentication modes, the device advertises its encryption mode within the 802.11 association request. For more information about the various 802.11 encryption modes, see 802.11 Encryption.

  • OID_802_11_SSID

    This OID queries or sets the service set identifier (SSID) of the network that the device associates with. When this OID is set, the device attempts to associate by using the other network parameters that have previously been configured.

After it is configured with the SSID of the network to associate with, the device will attempt the 802.11 association. If the association is successful, then the driver must make a media connect indication. Otherwise, the driver must make a media disconnect indication. For more information about these types of indications, see Media Status Indications for 802.11 Networks.

The following figure illustrates the OID flow typically used by the operating system for network configuration on the 802.11 device.

 

 

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