required_aggregates = []
    for requested_network in requested_networks:
        network_id = None
        subnet_id = None
        # Check for a specifically requested network ID.
        if "network_id" in requested_network and requested_network.network_id:
            network_id = requested_network.network_id
        elif "port_id" in requested_network and requested_network.port_id:
            # We have to lookup the port to get the network_id first.
            port = network_api.show_port(ctxt, requested_network.port_id)[
                "port"
            ]
            if port['fixed_ips']:
                subnet_id = port['fixed_ips'][0]['subnet_id']
            else:
                network_id = port["network_id"]
        if network_id:
            aggregates = utils.get_aggregates_for_routed_network(
                ctxt, network_api, report_api, network_id)
        if subnet_id:
            aggregates = list(utils.get_aggregate_for_segment(
            ctxt, network_api, report_api, subnet_id))
        if aggregates:
            required_aggregates.extend(aggregates)
            LOG.debug('routed_networks_filter request filter added '
                      'aggregates %s for network ID %s',
                      ','.join(aggregates),
                      network_id)