The capability of being able to print-by-reference might
be thought of as similar to the capability to be able to
print any given media type. In fact, print-by-reference
might be implemented by sending, instead of
application/vnd.adobe.postscript or application/vnd.hp.pcl,
> This strikes me as an easy feature to describe as a very small set
> of attributes which describe whether or not print-by-reference is
> supported and if so what identity the printer is configured to use
> and any network access restrictions it may have.
The difficult issue in print-by-reference is how the sender
supplies the credentials if any at all are required. There
is no single standard for identity in Internet protocols, and
there's no standard encapsulation of credentials.