For the names of the parts see Classless Inter-Domain Routing

#!/usr/bin/perl --
use strict;
use warnings;
use NetAddr::IP;
my $O =  NetAddr::IP->new( '10.12.100.0','255.255.252.0');
warn $O->mask(), ' ';
warn $O->masklen(), ' ';
__END__
255.255.252.0  at - line 6.
22  at - line 7.
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