PREFIX BASE: <http://schemas.ogf.org/nml/2013/05/base#>
PREFIX ndl-topology-owl: <http://cinegrid.uvalight.nl/owl/ndl-topology.owl#>
PREFIX sdndl: <http://www.gsi.dit.upm.es/ontologies/sdndl#>
PREFIX sdndlcao: <http://www.ctb.upm.es/ontologies/sdndlcao#>

SELECT DISTINCT STR(?vlan_id) AS ?vlan_id
                STR(?snapshot_id) AS ?snapshot_id
                STR(?timestamp_dist_node_start) AS ?timestamp_dist_node_start
                STR(?timestamp_dist_node_end) AS ?timestamp_dist_node_end

WHERE
      {
      ?interface_instance a  ndl-topology-owl:Interface;
                          sdndlcao:vlanId ?vlan_id;
                          sdndl:hasSnapshot ?snapshot_instance.
      ?snapshot_instance sdndlcao:snapshotId ?snapshot_id;
                         sdndlcao:snapshotOfScanningDevice ?scanningDevice_instance.
      ?scanningDevice_instance sdndlcao:timestampScanStart ?timestamp_dist_node_start;
                               sdndlcao:timestampScanEnd ?timestamp_dist_node_end
      }