The PortGroup and LinkGroup concepts require a "set of labels" concept. E.g. "VLAN 8,42,100-119". Here are two proposals how to represent this. Please pick one (personal preference, XML/RDF-fetish, or throwing a dice are valid selection mechanisms for today). Option 1. ========= XML: <nml:PortGroup id="urn:ogf:network:example.net:2010:mytrunk"> <nml:label> <nml:parameter name="type">vlan</nml:parameter> <nml:parameter name="set"> <nml:parameter name="value">8</nml:parameter> <nml:parameter name="value">42</nml:parameter> <nml:paramater name="range"> <nml:paramater name="start">100</nml:paramater> <nml:paramater name="end">119</nml:paramater> </nml:paramater> </nml:parameter> </nml:label> </nml:PortGroup> RDF: @prefix ex: <urn:ogf:network:example.net:2010> . @prefix nml: <http://example.ogf.org/schemas/nml/base/201303/> . @prefix nmlparam: <http://example.ogf.org/schemas/nml/param/201303/> . ex:mytrunk a nml:PortGroup . ex:mytrunk nml:label #12345678 . #12345678 nmlparam:type "vlan" . #12345678 nmlparam:set #9876543 . #9876543 nmlparam:value "8" . #9876543 nmlparam:value "42" . #9876543 nmlparam:range #asdfghj . #asdfghj nmlparam:start "100" . #asdfghj nmlparam:start "119" . Option 2. ========= XML: <nml:PortGroup id="urn:ogf:network:example.net:2010:mytrunk"> <nml:label> <nml:parameter name="type">vlan</nml:parameter> <nml:parameter name="values">8,42,100-119</nml:paramater> </nml:label> </nml:PortGroup> RDF: @prefix ex: <urn:ogf:network:example.net:2010> . @prefix nml: <http://example.ogf.org/schemas/nml/base/201303/> . @prefix nmlparam: <http://example.ogf.org/schemas/nml/param/201303/> . ex:mytrunk a nml:PortGroup . ex:mytrunk nml:label #12345678 . #12345678 nmlparam:type "vlan" . #12345678 nmlparam:values "8,42,100-119" . Thanks, Freek