{
    my $this_device;

    $this_device = \%InternalInterface if $is_internal;
    $this_device = \%ExternalInterface if $is_external;
    return unless $this_device;

    my $ethtool_options = $this_device->{EthtoolOpts};
    return unless $ethtool_options;

    return "ETHTOOL_OPTS=\"$ethtool_options\"";
}
