Wi-Fi (Compact 7)


Wi-Fi is a wireless technology based on the IEEE 802.11 standard. IEEE 802.11 defines the physical layer and media access control (MAC) sublayer for wireless communications.

The Native Wi-Fi automatic configuration component configures, connects to, and disconnects from wireless networks. Native Wi-Fi can store profiles on the networks it interacts with in the form of XML documents.

As a Windows Embedded Compact-based device moves from one location to another, automatic wireless network configuration searches for available wireless networks and notifies the device when there are new wireless networks available to which it can connect.

After it selects a wireless network, an automatic wireless network configuration updates the wireless network adapter to match the settings of that wireless network, and then attempts to connect to that wireless network.

These network adapter enhancements are integrated with security technologies. If authentication with one wireless access point or network does not succeed, the device will attempt to authenticate with the additional configured wireless networks.

The Windows Embedded Compact-based client device attempts to perform an 802.11 open authentication if the network adapter was preconfigured with a Wired Equivalent Privacy (WEP) key.

Media Sense, a part of the Network Driver Interface Specification (NDIS) technology, supports the detection of a move to a new wireless AP. When a move occurs, Media Sense forces a reauthentication to ensure consistent network connectivity. The Windows Embedded Compact-based wireless client also performs a Dynamic Host Configuration Protocol (DHCP) renewal of the IP address configuration for the wireless network adapter. The IP address configuration does not change within the same Extended Service Set (ESS). When the wireless client crosses an ESS boundary into a new subnet, the DHCP renewal obtains a new IP address configuration for that subnet.

Through Windows Sockets extensions, network-aware applications are notified of changes in network connectivity and can update their operation based on these changes. The reconfiguration and move detection minimizes the need for mobile IP when a wireless device roams to another subnet.

For information about developing a native 802.11 driver, see Native 802.11 Wireless LAN at MSDN.

To add this feature to your OS, see Wi-Fi Catalog Items and Sysgen Variables.

For samples, see Wi-Fi Profile Samples.

For reference information, see: Native Wi-Fi Reference

For information about wired equivalent privacy, see Wired Equivalent Privacy.

For information about Wi-Fi protected access, see Wi-Fi Protected Access and Wi-Fi Protected Access 2.

Source code for the Native Wi-Fi API sample can be found in the SDK installation location under C:\Program Files\Microsoft SDKs\Windows\<version number>\Samples\NetDs\Wlan\AutoConfig.