The MAC Protocol Data Unit (MPDU) is a protocol data unit (PDU) of the data link layer that consists of the MAC header, the MAC Service Data Unit (MSDU) and the Frame
Correction Sequence. The MAC header
iscomposed of the Frame Control Field
(FC) followed by thesequence number and the address field
. The MPDU is used to exchange messages between the different MAC instances of a network. If the MPDU is larger than the MAC Service Data Unit (MSDU), then the MPDU may contain multiple smaller MSDUs through aggregation. If the MPDU is smaller than the MSDU, then segmentation takes place. In WLANs according to 802.11ac, the MPDU has a maximum length of 11,454 bytes.