code: function (port, parent_port) {
  
  	// check if the port wasn't reported
  	if (l_ports.hasOwnProperty(port) === false) {
  		
  		LOG.warn('recording used port [' + port + ']...', 'SR.Monitor');	
  		l_ports[port] = parent_port || port;
  	}
  }
docs: record an existing port 'parent_port' indicats the which port, if released, will also release the current port