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An XML Schema for Exchanging Grid Network Measurements. Dan Gunter Monday, 6 October 2003 GGF9: Chicago, IL. Who will use this? Why XML?. Common language for OGSI grid services to communicate network measurements to other OGSI grid services
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An XML Schema for Exchanging Grid Network Measurements Dan Gunter Monday, 6 October 2003 GGF9: Chicago, IL
Who will use this? Why XML? • Common language for OGSI grid services to communicate network measurements to other OGSI grid services • XML Schema the most supported mechanism in this space for interoperable data exchange • Eventually: Ontologies!
Schema overview Name of characteristic being measured Characteristic Subject (src,dst,…) Network topology that the characteristic is measuring Methodology (tool(toolParams)) How the characteristic is measured Result-Set (result,summary)* Results of measurement
Flexibility Assumptions • Assume that all characteristics are not known in advance • Characteristic identified by a string, not a “type” • Relation between characteristics and tools not specified – assume tools come and go, and relation may be a many-to-many • Assume new “result” types are common, relation to tool/characteristic not known in advance: • Any result can appear for any characteristic / tool combination
Results • Allow multiple “raw” results to be combined with multiple “summary” results • Pre-defined summary types exist but they are extensible (base “SummaryData” type)
DelayResult diagram A little out of date: can occur zero or more times This stuff is all in DoubleResult
Topology • Most concepts in NM-WG document are represented (thanks to Bruce L.) • Multi-hop paths not yet implemented (but would be easy)
Tools and Parameters • Tool is named and versioned • Inputs to the tool, called “tool parameters” are selected from groups • Only 1 group now: IPToolParameters • Reporting any parameter is optional
Examples • iperf measurement from NTAF (slightly modified to show multiple results) • iperf_from_ntaf.xml • Ping measurement from NTAF • ping_from_ntaf.xml
“Demo” • Use XPath expressions on real NTAF results to find: • Most recent achievable bandwidth measurement on any path • Most recent round-trip between two specific hosts • All round-trip measurements, raw number only, between a host pair since October 3rd • By the way, what is XPath? • Xpath is the glob of XML • Will be “built in” to OGSI services • Xquery is the SQL-like big brother, not implemented much yet
Compare with CIM instance at InstanceDelay.xml • More compact; CIM-compatible(?) • Test-centric: characteristic name is buried in the “test settings” • Single topology (src/dst) • Results less flexible • Set of results for a characteristic pre-defined • No way to do time series • Summary elements not reusable • What is the “InstanceID”? • Hard to say more, since schema not available