my (@a, @b);
my @port_ifIndices = sort {
    if ($oids{ifName}{$a} =~ /\//) {
        @a = split(/\//, $oids{ifName}{$a});
        @b = split(/\//, $oids{ifName}{$b});
    }
    else {
        @a = $oids{ifName}{$a};
        @b = $oids{ifName}{$b};
    }
    if ($a[0] =~ /[A-Za-z]/) {
        $a[0] ne $b[0] ? $a[0] cmp $b[0] : ($a[1] <=> $b[1] ? $a[1] <=> $b[1] : $a[2] <=> $b[2]);
    } else {
        $a[0] != $b[0] ? $a[0] <=> $b[0] : ($a[1] <=> $b[1] ? $a[1] <=> $b[1] : $a[2] <=> $b[2]);
    }
} keys(%{ $oids{ifName} });

foreach my $ifIndex (@port_ifIndices) {
        print ("$ifIndex: $oids{ifName}{$ifIndex}\n");
}