/** * Does the substraction of this address with the given address. Each byte * substracts up separately with remainteds. No adderss may substract lower * than the :: address. * * @param Ipv6 $other */ public function substract(Ipv6 $other) { $new1 = $other->_not(); $new2 = $this->add($new1); return $new2->add(new Ipv6(array(0, 0, 0, 0, 0, 0, 0, 1))); }