my $server_root_dispersion_binary =  substr($received_data, 64, 32);
my $server_root_dispersion = oct("0b".$server_root_dispersion_binary);

##</code><code>##

my $server_root_dispersion = oct("0b" . substr($received_data, 64, 32));

##</code><code>##

my $server_precision = oct("0b" . substr($received_data, 24, 8));
my $server_root_delay = oct("0b" . substr($received_data, 32, 32));

##</code><code>##

my $server_precision = oct("0b" . substr($received_data, 24, 8));
my $server_root_delay = oct("0b" . substr($received_data, 24+8, 32));

##</code><code>##

my $server_precision = oct("0b" . substr($received_data, $here, ($width = 8)));
$here += $width;
my $server_root_delay = oct("0b" . substr($received_data, $here, ($width = 32)));
$here += $width;

##</code><code>##

if ($received_data) {
   my $here = 0;
   my $next_value = sub { 
      my $width = shift; 
      my $start = $here;
      $here += $width;
      return oct("0b".substr($received_data, $start, $width));
   };
   my $server_li = $next_value->(2);
   my $server_vn = $next_value->(3);
   my $server_mode = $next_value->(3);
   my $server_stratum = $next_value->(8);
   ...

##</code><code>##

if ($received_data) {
   my $here = 0;
   my ($server_li, $server_vn, $server_mode, $server_stratum, ... ) =
     map { 
        my $start = $here;
        $here += $_;
        return oct("0b".substr($received_data, $start, $_));
     }
      (2, 3, 3, 8, ... )

##</code><code>##

my ($server_li, $server_vn, $server_mode, $server_stratum, ... )
     map { oct("0b".$_) } unpack 'a2a3a3a8...', $received_data

##</code><code>##


our (@fields, %width, $packt);
{
  my @f = (
    # list of field names and widths in the order in which they appear
    li   => 2, 
    vn   => 3,
    mode => 3,
    (map {$_ => 8}  qw(stratum poll_interval precision)),
    (map {$_ => 32} qw(root_delay dispersion identifier)), 
    (map {$_ => 64} qw(ref_epoch originate_epoch receive_epoch transmit_epoch))
  );

  @fields = map {$f[$_*2]} (0 .. @f/2);
  %width = (@f);
  $packt = join '', map {"a$width{$_}"} @fields;
}

...

%srv = ();
@srv{@fields} = map { oct("0b".$_) } unpack $packt, $received_data;