A port is started in the state of LISTEN.

def up(self, role, root_priority, root_times):
        """ A port is started in the state of LISTEN.  """
        self.port_priority = root_priority
        self.port_times = root_times

        state = (PORT_STATE_LISTEN if self.config_enable
                 else PORT_STATE_DISABLE)
        self._change_role(role)
        self._change_status(state)