Wireless LAN API KB918997 for Windows XP SP2
Wireless LAN API KB918997 is a hotfix that adds a subset of the Native Wifi API functionality to Windows XP with Service Pack 2 (SP2). The Native Wifi API is a set of functions that allow applications to manage wireless network connections and profiles. The Native Wifi API was introduced in Windows Vista and is fully supported in Windows 7 and later versions. However, Windows XP with SP2 does not have this functionality by default, and requires the installation of the hotfix to enable it.
The Wireless LAN API KB918997 for Windows XP SP2 can be downloaded from the Microsoft Download Center. The hotfix requires a reboot after installation. The hotfix also updates the Wireless Zero Configuration (WZC) service, which is the default service that manages wireless connections on Windows XP. The WZC service can be disabled by setting the registry value HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WZCSVC\Start to 4.
The Wireless LAN API KB918997 for Windows XP SP2 supports a limited set of functions from the Native Wifi API. Some of the functions that are supported are:
WlanOpenHandle and WlanCloseHandle: These functions open and close a handle to the wireless service.
WlanEnumInterfaces and WlanQueryInterface: These functions enumerate and query the wireless interfaces on the system.
WlanScan and WlanGetAvailableNetworkList: These functions initiate and retrieve a scan of the available wireless networks.
WlanConnect and WlanDisconnect: These functions connect and disconnect from a wireless network.
WlanGetProfile, WlanSetProfile, WlanDeleteProfile, WlanGetProfileList, WlanSetProfileList, and WlanSetProfilePosition: These functions manage the wireless network profiles, which store the settings and credentials for connecting to a network.
WlanRegisterNotification: This function registers a callback function that receives notifications about wireless events, such as connection status changes.
WlanReasonCodeToString: This function converts a reason code, which indicates why an operation failed or succeeded, to a string.
WlanAllocateMemory and WlanFreeMemory: These functions allocate and free memory for the wireless structures and data.
The Wireless LAN API KB918997 for Windows XP SP2 does not support some of the features and functions that are available in the Native Wifi API on later versions of Windows. Some of the limitations are:
A profile can only be associated with one SSID, which is the name of a wireless network. On later versions of Windows, a profile can be associated with multiple SSIDs, which allows roaming between networks with different names but same settings.
The profile list, which determines the order of preference for connecting to networks, always places infrastructure networks before ad hoc networks. On later versions of Windows, the profile list can be customized by the user or the application.
The profile name is derived from the SSID, and cannot be changed by the user or the application. On later versions of Windows, the profile name can be set to any arbitrary string.
The physical layer (PHY) types, which indicate the wireless technology used by a network, such as 802.11a, 802.11b, 802.11g, or 802.11n, are not supported. On later versions of Windows, the PHY types can be queried and specified by the application.
The pairwise master key (PMK) caching, which allows faster reconnection to a network by reusing the previous authentication key, is not supported. On later versions of Windows, PMK caching can be enabled or disabled by the application.
The independent hardware vendor (IHV) extensibility functions, which allow vendors to provide custom extensions to the wireless service, such as proprietary authentication methods or diagnostics, are not supported. On later versions of Windows, IHV extensibility is supported by the Native Wifi API and the Wireless LAN Service.
The profile permissions, which control who can view, modify, or delete a profile, are not supported. On later versions of Windows, the profile permissions can be set to all-user or per-user by the application.
Only two notifications are available: wlan_notification_acm_connection_complete, which indicates that a connection attempt has completed, and wlan_notification_acm_disconnected, which indicates that a disconnection has occurred. On later versions of Windows, there are many more notifications that inform the application about various wireless events, such as network availability changes, profile changes, signal quality changes, etc.
The global 802.1X and EAPOL configuration settings, which affect how the system handles the authentication and encryption protocols for wireless networks, are not supported. On later versions of Windows, these settings can be queried and modified by the application.
The Wireless LAN API KB918997 for Windows XP SP2 is a useful hotfix that enables applications to use some of the features of the Native Wifi API on Windows XP with SP2. However, it is not a complete implementation of the Native Wifi API, and has some limitations and differences compared to later versions of Windows. For more information about the Wireless LAN API KB918997 for Windows XP SP2, see [Native Wifi API Support on Windows XP]. For more information about the Native Wifi API on later versions of Windows, see [About Native Wifi].
[Native Wifi API Support on Windows XP]
[About Native Wifi]