Found in upstream and downstream csit: https://logs.opendaylight.org/releng/jenkins092/netvirt-csit-1node-openstack-mitaka-upstream-transparent-boron/69/archives/odl1_karaf.log.gz

2016-12-14 14:03:07,341 | INFO | ool-47-thread-36 | ExternalRoutersListener | 326 - org.opendaylight.netvirt.natservice-impl - 0.3.2.SNAPSHOT | NAT Service : Add external router event for 259413fa-30ae-46a4-8854-1c97767a1634
2016-12-14 14:03:07,350 | INFO | ool-47-thread-36 | ExternalRoutersListener | 326 - org.opendaylight.netvirt.natservice-impl - 0.3.2.SNAPSHOT | NAT Service : Installing NAT default route on all dpns part of router 259413fa-30ae-46a4-8854-1c97767a1634
2016-12-14 14:03:07,351 | INFO | ool-47-thread-36 | NAPTSwitchSelector | 326 - org.opendaylight.netvirt.natservice-impl - 0.3.2.SNAPSHOT | NAT Service : Select a new NAPT switch for router 259413fa-30ae-46a4-8854-1c97767a1634
2016-12-14 14:03:07,351 | ERROR | ool-47-thread-36 | NAPTSwitchSelector | 326 - org.opendaylight.netvirt.natservice-impl - 0.3.2.SNAPSHOT | NAT Service : NAPT SWITCH SELECTION STOPPED DUE TO NO DPNS SCENARIO FOR ROUTER 259413fa-30ae-46a4-8854-1c97767a1634
2016-12-14 14:03:07,351 | ERROR | ool-47-thread-36 | ExternalRoutersListener | 326 - org.opendaylight.netvirt.natservice-impl - 0.3.2.SNAPSHOT | NAT Service : Unable to to select the primary NAPT switch
2016-12-14 14:03:07,351 | ERROR | ool-47-thread-36 | ExternalRoutersListener | 326 - org.opendaylight.netvirt.natservice-impl - 0.3.2.SNAPSHOT | NAT Service: Failed to get or allocated NAPT switch
2016-12-14 14:03:07,621 | INFO | CountersThread | CountersDumperThread | 276 - org.opendaylight.infrautils.counters-impl - 1.0.2.SNAPSHOT | dsjcc.jobs_pending: 4, dsjcc.jobs_cleared: +44 , nsc.subnetmap_update: +2 , nsc.subnetmap_add: +1, nsc.subnetmap_remove: +1