Subject: IPP> MOD optional attributes for more info and driver installer

From: [email-masked] (Zehler,Peter)
Date: Wed, 26 Feb 1997 08:16:48 PST

All,
     The ability to obtain more information about a printer or to 
 download the appropriate driver is outside the scope of
IPP version 1.  I am proposing 2 optional attributes be added to the 
 printer.  The attributes would be extensions of Printer
Description Attributes.  The attributes are printer-more-info and 
 printer-driver-installer.  These attributes are optional.
     The printer-more-info attribute is to be used to give the end user 
 a URI to obtain additional information. The URI is
intended to provide a hook for printer venders or pay-for-print 
 operations to interact with end users in ways outside the scope
of IPP(e.g. cost of a print job, locations of driver installers, map to 
 location).
     The printer-driver-installer attribute is a URI to a "installer 
 service".  The intention is that this is a programmatic
hook to obtain the appropriate driver.  Protocol specific mechanisms 
 will be used to obtain the driver installer for the correct
client environment. I have some HTTP specific examples below.  The use 
 of a simple URI here implies that no special
treatment of this attribute is implied.  The IPP printer does not 
 require any additional knowledge of the client environment to
satisfy the GetAttribute request.  The IPP protocol is not complicated 
 by the print driver installation hook.
     The two attributes should be in both the printer and directory 
 services.  Putting them in the printer permits client
usage of these attributes in environments that are not using a 
 directory service to represent their printers.  The attribute must
be in the printer when the printer is located by means outside 
 directory services(e.g. URI in magazine advertisement).
Inclusion of these attributes in the printer  also permits printer 
 vendors to provide factory default values enabling ease of
installation.  The value may be changed by printer configuration tools 
 or administrator operations in IPP version 2.  Inclusion
of these attributes in the directory schema permits ease of  
 administration.  Site specific policies can be quickly enacted.
     The use of these attributes are not mandatory.  I intend to 
 provide an informational RFC to codify their use.  This
informational RFC is not part of the IPP standard.  It is meant to 
 document how actual implementations of driver download
and additional information work in conjunction with IPP.
________________________
Example of multiple levels of driver installation service using IPP and HTTP
     Drivers already on client or install disk.  Use the Printer 
 Description Attribute, printer-model (or the proposed
printer-device-id), to determine which driver to install.  The driver 
 is already on your system, on the OS install disk, or a
vendor supplied printer install disk.  In this scenario the client OS 
 and language is known by the user and the appropriate
driver is selected by the user.  The driver install method is provided 
 by the OS.
     Driver installer on printer Home Page.  Use printer-more-info, to 
 locate print driver installer page for the printer.
Other mechanisms can be used to locate the page such as knowing the 
 printer vendors Home Page and following links,
advertisement, word of mouth etc.  An end user is required to interpret 
 the information on the print driver installer page and
select the appropriate driver installer for the client OS.  The 
 intention here is the printer Home Page is specific to the
associated printer.
     Driver installer obtained from URI in non-IPP fashion. Issue an 
 HTTP Get to the URI from the  printer-driver-
installer attribute to get the appropriate driver.  The Installer 
 provider can provide service in an implementation specific
fashion.  It may just default to some specific installer(eg NT 5.0).  A 
 super-Installer could be downloaded.  This would be
responsible for obtaining the parameters required to install the 
 appropriate driver in the client environment.  The third way a
provider may download the appropriate driver Installer is to look at 
 the product tokens in the HTTP Get request.  The tokens
and their formats are not standard and vary from browser to browser.
     Driver installer obtained from URI in IPP fashion.   Issue an HTTP 
 Get to the URI from the  printer-driver-installer
attribute to get the appropriate driver.  Included in the Get will be 
 IPP specific product tags.  The Installer will use IPP
product tags in the HTTP Get request to determine which installer to 
 download to the client.

Pete