Association is the process by which a WLAN station device connects to an Access Point.

The Association frame exchange for AP-Station connection which does not have any security enabled is the simplest association process and follows the below steps

1. The WLAN station device sends out a probe-request to the Access Point
2. On receipt of the Probe request – the Access point sends out a probe response if the parameters in the probe request sent by the Station are acceptable to it
3. The WLAN station device sends out an 802.11 authentication frame with authentication mode set to open system (This will be discussed more in 802.11 security and authentication mechanisms)
4. The Access Point responds with an 802.11 authentication success frame
5. On receipt of the 802.11 authentication frame from the Access point, the 802.11 station sends out an association request.
6. If the parameters sent in the association request is acceptable to the Access Point, the Access point sends a success Association response message
7. Since, no association or authentication is desired, data traffic can be enabled and now the Access point and the WLAN station can exchange data traffic packets

The Wireless packet capture showing the handshake described above is presented in the next article

Associating to an Access Point – wireless captures