DATA LINK LAYER
MSDU – MAC Service Data Unit
Service data unit received from the Layer 3 via the LLC
MPDU – MAC Protocol Data Unit
Data unit received from the LLC. MAC header is added and packaged resulting in an 802.11 frame.
This is where the FCS is added.
PLCP – Physical Layer Convergence Procedure
Check if media is clear for transmission
PMD – PHYSICAL MEDIA DEPENDENT
PPDU – PLCP Protocol Data Unit
The complete frame. Includes PLCP headers,MAC Headers, MAC data Field. MAC and PLCP trailers