This section specifies the Medium Access Control (MAC) Sublayer protocol data unit (PDU)
structures for the CEBus Network. The MAC PDU (MPDU) is the unit of data exchanged
between peer MAC entities. The MPDU consists of an "MPDU Header" and an "LPDU". The
LPDU is the LLC Protocol Data Unit, that is the data handed down from the LLC to the MAC for
transmission. (The LPDU is also referred to as a "MAC Service Data Unit" or "MSDU".) The
MPDU Header is data that the MAC Sublayer appends to the LPDU to properly deliver the
LPDU to its destination. Upon reception of an MPDU, the MPDU Header is stripped away by
the receiving MAC Sublayer, and the LPDU (or MSDU) is passed up to the destination's LLC
Sublayer.