Additional facilities available in this product that are not specified in the DFDL 1.0 specification.
A message is a global element that represents an entire data stream (rather than a structure within a larger data stream). Within a DFDL schema file, a message is represented by a special IBM® annotation on a global element.
Further information about DFDL
For more information about DFDL, see the Open Grid Forum web site. This site has tutorials on DFDL.