set Joiner UDP Port

        Args:
            portNumber: Joiner UDP Port number

        Returns:
            True: successful to set Joiner UDP Port
            False: fail to set Joiner UDP Port

def setUdpJoinerPort(self, portNumber):
        """set Joiner UDP Port

        Args:
            portNumber: Joiner UDP Port number

        Returns:
            True: successful to set Joiner UDP Port
            False: fail to set Joiner UDP Port
        """
        print '%s call setUdpJoinerPort' % self.port
        cmd = 'joinerport %d' % portNumber
        print cmd
        return self.__sendCommand(cmd)[0] == 'Done'