1. EXI Comparisions

2. EXI Emerging W3C standard, now in “final call” status on the standards track http://www.w3.org/XML/EXI/ Provides a more efficient, alternate way to encode the XML infoset. Relaxes XML requirement for text-only Can use schema information (if present) to encode XML document data more efficiently Can also work (less optimally) without a schema

3. EXI & Military This has big implications for the military We want XML for data interoperability But XML is too verbose to use on many military networks Poor string databinding characteristics push implementers to use custom binary protocols Which results in silos of exellence, and nobody able to use the anyone else’s data without a lot of custom programming

4. EXI Measures of Effectiveness: Document size Databinding performance The first is obvious: we want to use XML everywhere, but the documents can be too big. EXI can make documents smaller, while being exactly equivalent to the original XML The second less so: we want to be able to efficiently get data from the document to a programming language, such as Java, C++, Python, etc. The second is a hard problem to measure; all sorts of measures of effectiveness

5. XML & Gzip Why not just gzip XML? Doesn’t solve databinding issue at all For many XML documents with numeric data & a schema, EXI is more compact

6. Size Comparison: Single DIS PDU IEEE DIS144100% XML1387963% Gzipped XML545378% EXI (No schema) 752522% EXI (Schema) 11580% the size of original binary!

7. Size Comparison The Gzipped data has the inherent problems of databinding string data The IEEE binary format is understood only by DIS- savvy applications The EXI schema-informed format is smaller than the original binary IEEE format, but at the cost of somewhat higher parsing complexity The schema-less EXI format is fairly competitive with gzip (results vary depending on the nature of the data)