my %Hash_To_Send = (               
     LI_VN_Mode                    => '00100011' , # 8 bit
     Stratum                       => '0' ,        # 8 bit
     Poll                          => '0' ,        # 8 bit
     Precision                     => '0' ,        # 8 bit
     Root_Delay                    => '0' ,        # 32 bit
     Dispersion                    => '0' ,        # 32 bit
     Reference_Identifier          => '0' ,        # 32 bit
     Reference_Timestamp_Sec       => '0' ,        # 32 bit
     Reference_Timestamp_Micro_Sec => '0' ,        # 32 bit
     Originate_Timestamp_Sec       => '0' ,        # 32 bit
     Originate_Timestamp_Micro_Sec => '0' ,        # 32 bit
     Receive_Timestamp_Sec         => '0' ,        # 32 bit
     Receive_Timestamp_Micro_Sec   => '0' ,        # 32 bit
     Transmit_Timestamp_Sec        => '0' ,        # 32 bit
     Transmit_Timestamp_Micro_Sec  => '0' ,        # 32 bit
);

my @keys = qw(                     
     LI_VN_Mode                    
     Stratum                       
     Poll                          
     Precision                     
     Root_Delay                    
     Dispersion                    
     Reference_Identifier          
     Reference_Timestamp_Sec       
     Reference_Timestamp_Micro_Sec 
     Originate_Timestamp_Sec       
     Originate_Timestamp_Micro_Sec 
     Receive_Timestamp_Sec         
     Receive_Timestamp_Micro_Sec
     Transmit_Timestamp_Sec        
     Transmit_Timestamp_Micro_Sec  
);  

# get values in ordered mode for call with positional parameters
my @arraySendSntpPacket = @Hash_To_Send{@keys}; # hash slice!

my $result;

# two ways of calling:

# positional parameters
$result = positional_function( @arraySendSntpPacket );

# named parameters
$result = named_param_function( %Hash_To_Send );

sub positional_function {
    my @args = @_;
    # do something with $args[0], $args[1], ...
}

sub named_param_function {
    my %args = @_; # flattened list of key/value pairs
    # do something with $args{LI_VN_Mode}, $args{Stratum}, ...
}