- The Access points continuously sends out Beacon Frames which are picked up by the nearby wlan clients.
- The client can also broadcast on its own probe request frame on every channel
- Access points within range respond with a probe response frame
- The client decides which access point (AP) is the best for access and sends an authentication request
- The access point will send an authentication reply
- Upon successful authentication, the client will send an association request frame to the access point
- The access point will reply with an association response
- The client is now able to pass traffic to the access point
Beacon frame is one of the management frames in IEEE 802.11 based WLANs. It contains all the information about the network. Beacon frames are transmitted periodically, they serve to announce the presence of a wireless LAN and to synchronise the members of the service set. Beacon frames are transmitted by the access point (AP) in an infrastructure basic service set (BSS). In IBSS network beacon generation is distributed among the stations. Beacons are sent periodically at a time called Target Beacon Transmission Time(TBTT) 1 TU = 1024 microseconds Beacon interval =100 TU (100x 1024 microseconds or 102.4 milliseconds) 1. Timestamp (8 byte) 2. Beacon Interval (2 byte) 3. Capability info (2 byte) 4. SSID (variable size) 5. Supported Rates (variable size) Probe Request: A station or client becomes active or on a PC when the wlan card it enabled it becomes acti...
Comments
Post a Comment