1.1.27 Client - Station APIs
This interface allows the WINCS02 to connect to a BSS as a station.
The function WDRV_WINC_BSSConnect is provided to perform the connection operation. This function accepts both a BSS context and an Authentication context to describe the BSS and security of the connection.
The structure WDRV_WINC_CONN_CFG is used to further configure the connection. This is an optional parameter to WDRV_WINC_BSSConnect, impacting network layers, connection timeout and roaming. The function WDRV_WINC_BSSDefaultWiFiCfg is provided to initialize the structure to default values suitable for a BSS connect.
The function WDRV_WINC_BSSDisconnect is provided to disconnect from a connected BSS.
Roaming
802.11 roaming is a feature that allows a WLAN station to transition between multiple Access Points within an Extended Service Set (ESS). An ESS is created when a collection of Access Points share the same wired network and provide the same Wi-Fi network name (Service Set Identifier or SSID). The purpose of roaming is to automatically connect to another AP within the ESS when the existing AP connection becomes unusable, such as when the station moves out of range.
An AP participating in an ESS is expected to share not only the same Wi-Fi network name but also to be on the same Local Area Network (LAN). Thus, roaming enables a station to change its Access Point while remaining connected to the IP layer network.
In Station mode, the WINCS02 will roam upon detecting a link-loss with the existing Access Point (AP). Link-loss is detected by tracking the beacons of the associated AP, and a prolonged absence of beacons triggers the roaming function in the WINCS02. Additionally, the WINCS02 station will send keep-alive (NULL) frames to the AP to maintain the link during periods of network inactivity.
ISO/OSI Layer 2 roaming occurs when the WINCS02 roams from one AP to another AP, allowing it to maintain the same IP address. Layer 3 roaming occurs when the WINCS02 roams from one AP to another AP in a different subnet, requiring a new IP address to be obtained.
Roaming can be configured using the function WDRV_WINC_BSSRoamingConfigure, this takes a WDRV_WINC_BSS_ROAMING_CFG structure parameter and indicates if roaming is performed at network layer 2 or 3 or not at all.