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This document is one of a set of documents which together describe all aspects of a new Internet Printing Protocol (IPP). IPP is an application level protocol that can be used for distributed printing using Internet tools and technology. The protocol is heavily influenced by the printing model introduced in the Document Printing Application (ISO/IEC 10175 DPA) standard. Although DPA specifies both end user and administrative features, IPP version 1.0 is focused on end user functionality. Although DPA specifies both end user and administrative features, IPP version 1.0 is focused only on end user functionality.
The full set of IPP documents includes:
Internet Printing Protocol : Requirements
Internet Printing Protocol/1.0: Model and Semantics
Internet Printing Protocol/1.0: Security
Internet Printing Protocol/1.0: Protocol Specification
Internet Printing Protocol/1.0: Directory Schema
The requirements document takes a broad look at distributed printing functionality, and it enumerates real-life scenarios that help to clarify the features that need to be included in a printing protocol for the Internet. It identifies requirements for three types of users: end users, operators, and administrators. The requirements document calls out a subset of end user requirements that must be satisfied in the first version of IPP. Operator and administrator requirements are out of scope for v1.0. The model and semantics document describes a simplified model with abstract objects, their attributes, and their operations. The security document covers potential threats and proposed counters to those threats. The protocol specification incorporates the ideas in all the other documents into a concrete mapping using clearly defined data representations and transport protocol mappings that real implementers can use to develop interoperable client and server side components. Finally, the directory schema document shows a generic schema for directory service entries that represent instances of IPP Printers.
This document is the “Internet Printing Protocol/1.0: Directory Schema” docuument.
Table of Contents
A Directory Service is a means by which service users can locate service providers. The directory contains entries for each type of object within the system: entries for users, file systems, servers, applications, printers, other devices, etc. End users use a Directory Service to locate objects based on naming and organizational contexts. For example, find all servers in the "Local Department" context. Authentication and authorization are also often part of a directory service. Users are only allowed to find objects to which they have certain access rights. Each service provider registers with the directory (either automatically or with the help of an administrator) as an entry of a certain type. For example, an IPP Printer can be registered in the directory as a Printer object with certain registration attributes (name, address, static characteristics, etc.). Given a Directory Service provides this type of interaction for both service providers and service users, it is possible for end users to locate an IPP Printer using either a simple name lookup or a filtered attribute search.
After an end user locates one or more IPP Printers, the end user selects a Printer. Certain attributes in the directory entry for a Printer provide additional information to the end user, such as the cost to print jobs on this Printer, that assist the end user in selecting a Printer.
After an end user selects an IPP Printer, the end user performs an IPP print operation on that Printer. IPP provides the protocol that communicates this print operation to the IPP Printer in the network. An IPP client addresses an IPP Printer using a URI. This URI is a required attribute in the directory entry for an IPP Printer. Thus, the Printer’s URI “links” the directory entry for an IPP Printer to the corresponding IPP Printer in the network.
IPP does not require any specific Directory Service provider. However, this specification does define a generic schema that can be used to implement directory entries for Printers using a specific Directory Service.
Section 2 introduces the generic schema for entries in a directory that represent IPP Printer objects.
Sections 3-5 cover security, technical references, and author contact information.
Directory Entry Schema
The following attributes define the generic directory entry schema for an IPP Printer. The conformance terminology, the syntax definitions of the attributes and the values of the attributes are defined in the “Internet Printing Protocol/1.0 Model and Semantics” document and are not repeated in this document. The attribute definitions in this schema match the corresponding attribute definitions in the model to facilitate manual and/or automatic mechanisms of mapping an IPP Printer to its corresponding directory entry.
All MANDATORY attributes MUST be defined in each directory entry for an IPP Printer. All other attributes SHOULD be defined in each directory entry for an IPP Printer. Furthermore, a directory entry for an IPP Printer SHOULD be an instance of a Printer object class defined by the Directory Service to scope searches for Printers. Finally, a directory entry for an IPP Printer SHOULD reflect the current attribute values for an IPP Printer in the network at any point in time.
printer-URI (uri, MANDATORY)
This attribute contains the URI for the Printer. An administrator shall determine a printer's URI and shall set this attribute to that URI. The precise format of a printer URI SHALL be implementation dependent.
printer-name (name, MANDATORY)
This attribute contains the name of the Printer. It is a name that is more user friendly than the printer-URI. An administrator shall determine a Printer's name and shall set this attribute to that name. This name may be the last part of the printer's URI or it may be unrelated. In non-US-English locales, a name may contain characters that are not allowed in a URI.
This attribute identifies the location of this Printer.
In order for filtered searches to be more effective, a given site may use some regular structuring within the attribute value such as "SITE:USA-San Jose,BUILDING:A1,FLOOR:2,ROOM:555" or "department5-2ndFloor-A5-IndianHills-Chicago-IL-USA".
This attribute identifies the descriptive information about this Printer. This could include things like: "This printer can be used for printing color transparencies for HR presentations", or "Out of courtesy for others, please print only small (1-5 page) jobs at this printer", or even "this printer is going away on July 1, 1997, please find a new printer".
This attribute contains a URI used to obtain more information about this specific Printer. The information obtained from this URI is intended for end user consumption. Features outside the scope of IPP can be accessed from this URI. The information is intended to be specific to this Printer and site services (e.g. job pricing, services offered, end user assistance). The manufacturer may initially populate this attribute.
This attribute identifies the make and model of the printer.
This attribute contains a URI used to obtain more information about this type of printer. The information obtained from this URI is intended for end user consumption. Features outside the scope of IPP can be accessed from this URI. (e.g. latest firmware, upgrades, print drivers, optional features available). The information is intended to be germane to this printer without regard to site specific modifications or services.
media-supported (1setOftype4 keyword)
This attribute identifies the media supported by the Printer. This directory attribute SHOULD only be updated with values that are relatively static values, not values which are constantly being updated by the Printer.
number-up-supported (1setOftype3 keyword)
This attribute specifies the number of source page-images to impose upon a single side of an instance of a selected medium.
sides-supported (1setOftype2 keyword)
This attribute specifies how source page-images are to be imposed upon the sides of an instance of a selected medium.
This attribute specifies the locales that the Printer operates in.
An end user’s access to a directory entry for an IPP Printer is controlled by the Directory Service. An end user’s access to an IPP Printer in the network is controlled by the service provider for that IPP Printer.
NOTE: There is another Internet-Draft called "Internet Printing Protocol/1.0: Security." That document is being drafted and reviewed in parallel with this document. Before this document can become a formal RFC, any relevant issues from that document will be rolled into this one.
 Internet Printing Protocol: Requirements.
 Internet Printing Protocol/1.0: Model and Semantics.
 Internet Printing Protocol/1.0: Security.