The DDMS is designed using a layered approach, combining a Core Layer and an Extensible Layer surrounded by the DDMS Resource Header. The Core Layer is composed of five sets of element categories, each with a specific functional focus for describing a data asset: • The Metacard elements describe the DDMS resource itself. • The Security elements enable the description of security classification of the described resource, Need-to-Know (NTK) information, and related notices. • The Resource elements enable the description of maintenance and administration information. • The Summary Content elements enable the description of concepts and topics. • The Format elements enable the description of physical attributes of the asset. • The Extensible Layer is designed to support domain-specific or
Community of Interest (COI) discovery
metadata requirements, and can be used to extend the element categories identified in the Core Layer. Extensions are expected to be registered in the DoD Metadata Registry. Extensible attribute spaces are also provided on some elements. == Earlier versions ==