Roman, Jeroen, While we're here together I still like a short discussion on identifiers for relations. Currently, it is just a string in XML. e.g. "isSink", "hasPort" However, it is a full URL in RDF, e.g. "http://schemas.ogf.org/nml/2013/10/relation#isSink", "http://schemas.ogf.org/nml/2013/10/relation#hasPort". So the translation is to simply prefix the XML-identifier with a fixed (special-purpose) URI. So far I used "http://schemas.ogf.org/nml/2013/10/relation#". However, as we found at the previous OGF, this is a problem when a new version of NML is defined in the future, with possibly more relations. Eg.: "http://schemas.ogf.org/nml/2016/08/relation#isSink". In that case, it is no longer clear which URL should be prepended to the base name ("isSink"). I can see two solutions: 1. Append the namespace of the element when translating. E.g. <nml:Topology xmlns:nml="http://schemas.ogf.org/nml/2013/10/base#"> ... <nml:Relation type="isSink"> becomes "http://schemas.ogf.org/nml/2013/10/base#isSink" (thus not "http://schemas.ogf.org/nml/2013/10/relation#isSink") 2. Don't translate relation identifier between XML and RDF, and use full URI in XML (yes, it's ugly, but it's simple): <nml:Relation type="http://schemas.ogf.org/nml/2016/08/relation#isSink"> Can we talk this over during a break today? Freek