$MSK = pack('N4', -1 << (32 - $LEN));
$BRD = join(".", unpack('C4', $ADR | ~$MSK));
$MAC = "fe:fd:" . join(":", map { sprintf "%02x", $_ } unpack('C4', $ADR));
$MSK = pack('N4', -1 << (32 - $LEN));
$BRD = join(".", unpack('C4', $ADR | ~$MSK));
$MAC = "fe:fd:" . join(":", map { sprintf "%02x", $_ } unpack('C4', $ADR));