Command to start the Dynamips hypervisor process.
        (to be passed to subprocess.Popen())

def _build_command(self):
        """
        Command to start the Dynamips hypervisor process.
        (to be passed to subprocess.Popen())
        """

        command = [self._path]
        command.extend(["-N1"])  # use instance IDs for filenames
        command.extend(["-l", "dynamips_i{}_log.txt".format(self._id)])  # log file
        # Dynamips cannot listen for hypervisor commands and for console connections on
        # 2 different IP addresses.
        # See https://github.com/GNS3/dynamips/issues/62
        if self._console_host != "0.0.0.0" and self._console_host != "::":
            command.extend(["-H", "{}:{}".format(self._host, self._port)])
        else:
            command.extend(["-H", str(self._port)])
        return command