@Override
    public boolean isInfrastructure(Topology topology, ConnectPoint connectPoint) {
        checkNotNull(connectPoint, CONNECTION_POINT_NULL);
        return defaultTopology(topology).isInfrastructure(connectPoint);
    }
@Test
    public void testIsInfrastructure() {
        VirtualNetwork virtualNetwork = setupVirtualNetworkTopology();

        TopologyService topologyService = manager.get(virtualNetwork.id(), TopologyService.class);
        Topology topology = topologyService.currentTopology();

        VirtualDevice srcVirtualDevice = getVirtualDevice(virtualNetwork.id(), DID1);
        VirtualDevice dstVirtualDevice = getVirtualDevice(virtualNetwork.id(), DID4);
        ConnectPoint cp1 = new ConnectPoint(srcVirtualDevice.id(), PortNumber.portNumber(1));
        ConnectPoint cp2 = new ConnectPoint(dstVirtualDevice.id(), PortNumber.portNumber(2));

        // test the isInfrastructure() method.
        Boolean isInfrastructure = topologyService.isInfrastructure(topology, cp1);
        assertTrue("The connect point should be infrastructure.", isInfrastructure);

        isInfrastructure = topologyService.isInfrastructure(topology, cp2);
        assertFalse("The connect point should not be infrastructure.", isInfrastructure);
    }