Add a link item for processing later

        :param int src_id: Source node ID
        :param int src_port: Source port ID
        :param str src_port_name: Source port name
        :param dict destination: Destination

def calc_link(self, src_id, src_port, src_port_name, destination):
        """
        Add a link item for processing later

        :param int src_id: Source node ID
        :param int src_port: Source port ID
        :param str src_port_name: Source port name
        :param dict destination: Destination
        """
        if destination['device'] == 'NIO':
            destination['port'] = destination['port'].lower()

        link = {'source_node_id': src_id,
                'source_port_id': src_port,
                'source_port_name': src_port_name,
                'source_dev': self.node['properties']['name'],
                'dest_dev': destination['device'],
                'dest_port': destination['port']}

        self.links.append(link)