docs: def calc_device_links(self):
          """
          Calculate a router or VirtualBox link
          """
          for connection in self.interfaces:
              int_type = connection['from'][0]
              int_name = connection['from'].replace(int_type,
                                                    PORT_TYPES[int_type.upper()])
              # Get the source port id
              src_port = None
              for port in self.node['ports']:
                  if int_name == port['name']:
                      src_port = port['id']
                      break
              dest_temp = connection['to'].split(' ')
  
              if len(dest_temp) == 2:
                  conn_to = {'device': dest_temp[0],
                             'port': dest_temp[1]}
              else:
                  conn_to = {'device': 'NIO',
                             'port': dest_temp[0]}
  
              self.calc_link(self.node['id'], src_port, int_name, conn_to)