The ability to interoperate is defined by the metadata provided. At all levels there are two groups of metadata:

• Syntactic metadata - Information about the data types and structures at the computer level; often referred to as the data model.
  • Data types: byte, float, integer,...
  • Data structures: list, sequence, array,...
  
  
• Semantic metadata --- Information about the content of the data; what the variables mean, their ranges,...