Hi, At the moment there is a discussion on the NSI mailinglist about the preferred syntax for NSI topology descriptions. There is now an example document at https://github.com/jeroenh/AutoGOLE-Topologies/blob/nsiv2/goles/nordu.net.xm... I've tried to do some XML schema verification on that file, and I've got it down to two errors: goles/nordu.net.xml:2: element Topology: Schemas validity error : Element '{http://schemas.ogf.org/nml/2012/10/base#}Topology', attribute 'version': '20120814' is not a valid value of the atomic type 'xs:dateTime'. goles/nordu.net.xml:64: element Node: Schemas validity error : Element '{http://schemas.ogf.org/nml/2012/10/base#}Node': This element is not expected. Expected is ( {http://schemas.ogf.org/nml/2012/10/base#}Relation ). goles/nordu.net.xml fails to validate The first I understand sort of, some kind of strict typing must occur. The second problem I'm not sure, I thought we had defined the hasPort relation to be defined as an implicit relation, so it should be necessary to define it? Jeroen.