IEEE 802.11 Frame Format

The 802.11 frame format is used in wireless LANs (Wi-Fi) and differs from Ethernet due to the wireless environment's unique requirements, like mobility and signal integrity.

Structure of an 802.11 Frame

Frame Control (2 bytes):
Contains protocol version, type/subtype, and flags (e.g., retry, power management).

Duration/ID (2 bytes):
Specifies the time for the medium to be reserved.
Used for Network Allocation Vector (NAV) and managing communication.

Address Fields (6 bytes each):
Address 1: Destination MAC address (receiver).
Address 2: Source MAC address (transmitter).
Address 3: MAC address of the Distribution System (e.g., router or access point).

Sequence Control (2 bytes):
Helps manage fragments and reassemble frames in the correct order.

Payload/Data (Variable):
Contains the actual data or message to be delivered.
Frame Check Sequence (FCS) (4 bytes):
CRC for error checking and ensuring data integrity.