protected function get_iauthority() {
		if ($this->iuserinfo === null && $this->ihost === null && $this->port === null) {
			return null;
		}

		$iauthority = '';
		if ($this->iuserinfo !== null) {
			$iauthority .= $this->iuserinfo . '@';
		}
		if ($this->ihost !== null) {
			$iauthority .= $this->ihost;
		}
		if ($this->port !== null) {
			$iauthority .= ':' . $this->port;
		}
		return $iauthority;
	}