Protocol Data Units (PDUs) are the message formats exchanged between peer application entities within a layer. A PDU consists of protocol control information and user data and are constructed using mandatory fixed fields followed by optional variable fields that contain one or more items and/or sub-items.
The DICOM Upper Layer protocol consists of seven Protocol Data Units:
PDUs should be encoded as binary data prior to being sent to a peer
Application Entities using the
encode() class method. Each encoded PDU has
as its first byte value a corresponding PDU Type:
The encoding of DICOM Upper Layer PDUs is always Big Endian byte ordering.