Hi, I've been thinking about the relation syntax. So far, we have seen these two proposals: <nml:link id="urn:ogf:network:example.net:link_A-to-C"> <nml:relation type="serialcompound"> ... </nmlserialcompound:relation> </nml:link> and: <nml:link id="urn:ogf:network:example.net:link_A-to-C"> <nmlserialcompound:relation> ... </nmlserialcompound:relation> </nml:link> The advantage of the first syntax is that it is very easily extendable, and it is still obvious for a parser to understand that it is some kind of nml:relation, even if the particular type of relation is not known by the parser. The advantage of the second syntax is that it is easy to create a meaningful validator for each specific nml:relation. I dislike both syntaxes, and was hoping for a syntax that would provide both benefits. If I'm correct, the following syntax will do just that: <nml:link id="urn:ogf:network:example.net:link_A-to-C"> <nml:relations> <nmlserialcompound:relation> ... </nmlserialcompound:relation> </nml:relations> </nml:link> This adds a parent element to the relation elements, signifying that <nmlserialcompound:relation> is indeed a nml:relation. So even a parser that has no knowledge about this particular nml:relation still knows it's base syntax, while a parser that understands the details can still use an meaningful syntax validator (such as XSD) to make sure the syntax is correct. Would this do, and is this syntax acceptable to all? Regards, Freek