#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;
use XML::Twig;

my $xmlStr = <<XML;
<config>
 <one id="msn" type="shopping">
   <traffic>
       <daily value="on" />
       <weekly value="off" />
       <monthly value="off" />
   </traffic>
  </one>

 <one id="movies" type="entertainment">
   <traffic>
       <daily value="on" />
       <weekly value="off" />
       <monthly value="on" />
   </traffic>
 </one>

 <one id="espn" type="sports">
  <traffic>
      <daily value="on" />
      <weekly value="on" />
      <monthly value="on" />
      <hyper value="true" />
  </traffic>
 </one>
</config>
XML

my @ids;
my $t = XML::Twig->new();
$t->parse($xmlStr);
for my $one (  ($t->root()->children('one')  ) {
    for my $month  (  ($t->root()->children('monthly')  ) {
           if ( $momth->att('value') eq 'on' ) {
                  push @ids, $one->att('id');
           }
    }
}
print Dumper(\@ids);