8. The medium of claim 7, where each dictionary includes multiple sub-dictionaries each sub-dictionary exclusively containing dictionary index codes of a single type of data object.
8. The medium of claim 7, where each dictionary includes multiple sub-dictionaries each sub-dictionary exclusively containing dictionary index codes of a single type of data object. 9. The medium of claim 8, the flags further including one or more sub-dictionary identifiers identifying sub-dictionaries containing the dictionary index codes in the composed message.