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GCN Home > 08/02/04 issue

XML standards battle is brewing over Navy’s data-sharing plans

By Joab Jackson, GCN Staff

Proposed Navy rules for Extensible Markup Language use are forcing other agencies to take a stand on how they share and reuse data.

The Navy plans to adopt international interoperability standards that would eliminate document type definitions, or DTDs, which many agencies now use for sharing documents. Newer XML schemas are more suited to individual data elements.

The CIO Council took the Navy’s 2001 XML developer’s guide as the basis for its own 2002 governmentwide guide, at xml.gov. Now the Navy is further standardizing use of XML elements, attributes, types and schemas across all service programs, said Robert Green, XML interoperability team leader in the Navy CIO’s office.

XML is part of several initiatives to make the Navy network-centric. “We are looking at XML from a strategic and tactical perspective, not just as a convenient mechanism for describing markup” of documents, Green said.

The original guide “was the Navy’s first attempt at standardizing XML development,” Green said, and it left some questions unanswered. For example, it did not say whether program managers should follow the World Wide Web Consortium’s XML Schemas standard for shared vocabularies across platforms.

The new rulebook endorses the W3C XML component recommendations, as well as others from the International Standards Organization, the Organization for the Advancement of Structured Information Standards, the OASIS Universal Business Language technical committee, and the United Nations Centre for Trade Facilitation and Electronic Business.

By adhering to worldwide standards, the Navy intends to base its future applications more heavily on commercial products, Green said, in accordance with Office of Management and Budget Circular A-119, which encourages voluntary consensus standards.

XML salad

A set of XML naming rules will let different Navy programs share their XML components, Green said. “Rules ensure that every XML instance of a document will be consistent,” he said. “Contractors will know exactly what is required and will not be presented with competing requirements for different entities.”

The new guide warns program managers to steer clear of proprietary XML extensions. “Many vendors add customizations to specifications, in an attempt to build market share,” but customization leads to proprietary implementations and costly middleware, Green said.

Two years ago the Government Accountability Office, then the General Accounting Office, also warned agencies against proprietary XML extensions in its report, Electronic Government: Challenges to Effective Adoption of the Extensible Markup Language.

The fact that the core XML standard is nonproprietary does not ensure that all applications built with it will interoperate. “It is easy [for a vendor application] to add elements to an XML document that place unique processing requirements and restrictions on the document, preventing other systems from being able to interpret it,” GAO said.