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RFC 2567 - Design Goals for an Internet Printing Protocol


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Network Working Group                                       F.D. Wright
Request for Comments: 2567                        Lexmark International
Category: Experimental                                       April 1999

             Design Goals for an Internet Printing Protocol

Status of this Memo

   This memo defines an Experimental Protocol for the Internet
   community.  It does not specify an Internet standard of any kind.
   Discussion and suggestions for improvement are requested.
   Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (1999).  All Rights Reserved.

IESG Note

   This document defines an Experimental protocol for the Internet
   community.  The IESG expects that a revised version of this protocol
   will be published as Proposed Standard protocol.  The Proposed
   Standard, when published, is expected to change from the protocol
   defined in this memo.  In particular, it is expected that the
   standards-track version of the protocol will incorporate strong
   authentication and privacy features, and that an "ipp:" URL type will
   be defined which supports those security measures.  Other changes to
   the protocol are also possible.  Implementers are warned that future
   versions of this protocol may not interoperate with the version of
   IPP defined in this document, or if they do interoperate, that some
   protocol features may not be available.

   The IESG encourages experimentation with this protocol, especially in
   combination with Transport Layer Security (TLS) [RFC2246], to help
   determine how TLS may effectively be used as a security layer for
   IPP.

Abstract

   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 technologies.  This 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 design goals document calls out a subset of end
   user requirements that are satisfied in IPP/1.0. Operator and
   administrator requirements are out of scope for version 1.0.

   The full set of IPP documents includes:

   Design Goals for an Internet Printing Protocol (this document)
   Rationale for the Structure and Model and Protocol for the
   Internet Printing Protocol [RFC2568]
   Internet Printing Protocol/1.0: Model and Semantics [RFC2568]
   Internet Printing Protocol/1.0: Encoding and Transport [RFC2565]
   Internet Printing Protocol/1.0: Implementer's Guide [ipp-iig]
   Mapping between LPD and IPP Protocols [RFC2569]

   The "Rationale for the Structure and Model and Protocol for the
   Internet Printing Protocol" document describes IPP from a high level
   view, defines a roadmap for the various documents that form the suite
   of IPP specifications, and gives background and rationale for the
   IETF working group's major decisions.

   The "Internet Printing Protocol/1.0: Model and Semantics" document
   describes a simplified model consisting of abstract objects, their
   attributes, and their operations that is independent of encoding and
   transport.  The model consists of a Printer and a Job object.  The
   Job optionally supports multiple documents.  IPP 1.0 semantics allow
   end-users and operators to query printer capabilities, submit print
   jobs, inquire about the status of print jobs and printers, and cancel
   print jobs.  This document also addresses security,
   internationalization, and directory issues.

   The "Internet Printing Protocol/1.0: Encoding and Transport" document
   is a formal mapping of the abstract operations and attributes defined
   in the model document onto HTTP/1.1.  It defines the encoding rules
   for a new Internet media type called "application/ipp".

   The "Internet Printing Protocol/1.0: Implementer's Guide" document
   gives insight and advice to implementers of IPP clients and IPP
   objects.  It is intended to help them understand IPP/1.0 and some of
   the considerations that may assist them in the design of their client
   and/or IPP object implementations.  For example, a typical order of
   processing requests is given, including error checking.  Motivation
   for some of the specification decisions is also included.

   The "Mapping between LPD and IPP Protocols" document gives some
   advice to implementers of gateways between IPP and LPD (Line Printer
   Daemon) implementations.

TABLE OF CONTENTS

   1. INTRODUCTION.....................................................4
   2. TERMINOLOGY......................................................4
   3. DESIGN GOALS.....................................................6
   3.1. End-user.......................................................6
   3.1.1. Finding or locating a printer................................6
   3.1.2. Create an instance of the printer............................7
   3.1.3. Viewing the status and capabilities of a printer.............7
   3.1.4. Submitting a print job.......................................8
   3.1.5. Viewing the status of a submitted print job..................9
   3.1.6. Canceling a Print Job........................................9
   3.2. Operator (NOT REQUIRED FOR V1.0)...............................9
   3.2.1. Alerting.....................................................9
   3.2.2. Changing Print and Job Status...............................10
   3.3. Administrator (NOT REQUIRED FOR v1.0).........................10
   4. OBJECTIVES OF THE PROTOCOL......................................10
   4.1. SECURITY CONSIDERATIONS.......................................11
   4.2. Interaction with LPD (RFC1179)................................12
   4.3. Extensibility.................................................12
   4.4. Firewalls.....................................................13
   4.5. Internationalization..........................................13
   5. IPP SCENARIOS...................................................13
   5.1. Printer Discovery.............................................14
   5.2. Driver Installation...........................................15
   5.3. Submitting a Print Job........................................15
   5.4. Getting Status/Capabilities...................................16
   5.5. Asynchronous Notification.....................................17
   5.6. Job Canceling.................................................17
   6. Security Considerations.........................................18
   7. REFERENCES......................................................18
   8. ACKNOWLEDGMENTS.................................................19
   9. AUTHOR'S ADDRESS................................................19
   10. APPENDIX - DETAILED SCENARIOS..................................20
   10.1. Printer discovery within an enterprise.......................20
   10.2. Printer discovery across enterprises.........................21
   10.3. Printer discovery on the Internet -logical operations........21
   10.4. Printer discovery on the Internet - authentication...........22
   10.5. Driver Download..............................................23
   10.6. Submitting a print job as a file.............................24
   10.7. Submitting a print job with two documents....................24
   10.8. Submitting a print job as a file, printing fails.............25
   10.9. Submitting a print job with authentication, PRIVACY and
         payment......................................................26
   10.10. Submitting a print job with decryption error................27
   10.11. Submitting a print job with authentication..................28
   10.12. Submitting a print job generated dynamically................29
   10.13. Submitting a print job with a Printer jam - CANCELED........29

   10.14. Submitting a print job with a Printer jam - recovered.......30
   10.15. Submitting a print job with server pull.....................31
   10.16. Submitting a print job with referenced resources............32
   10.17. Getting Capabilities........................................33
   10.17.1. Submission Attributes.....................................33
   10.17.2. Printer Capabilities......................................33
   10.18. Getting Status..............................................34
   10.18.1. Printer State/Status......................................34
   10.18.2. Job Status................................................34
   10.18.3. Status of All My Jobs.....................................34
   10.19. Asynchronous Notification...................................35
   10.19.1. Job Completion............................................35
   10.19.2. Job Complete with Data....................................35
   10.19.3. Print Job Fails...........................................35
   10.20. Cancel a job................................................36
   10.21. End to end Scenario - within an enterprise..................36
   10.22. End to end Scenario - across enterprises....................37
   10.23. End to End Scenario - on the internet.......................40
   11. Full Copyright Statement.......................................43

1. INTRODUCTION

   The IPP protocol is heavily influenced by the printing model
   introduced in the Document Printing Application (DPA) [ISO10175]
   standard.  Although DPA specifies both end user and administrative
   features, IPP version 1.0 (IPP/1.0) focuses only on end user
   functionality.

2. TERMINOLOGY

   Internet Printing for the purposes of this document is the
   application of Internet tools, programs, servers and networks to
   allow end-users to print to a remote printer using, after initial
   setup or configuration, the same methods, operations and paradigms as
   would be used for a locally attached or a local area network attached
   printer.  This could include the use of HTTP servers and browsers and
   other applications for providing static, dynamic and interactive
   printer locating services, user installation, selection,
   configuration, print job submission, printer capability inquiry and
   status inquiry of remote printers and jobs.

   For the purposes of this document, a WEB Browser is software
   available from a number of sources including but not limited to the
   following:  Microsoft Internet Explorer, NCSA Mosaic, Netscape
   Navigator, Sun Hot Java!.  The major task of these products is to use
   the Hypertext Transport Protocol (HTTP) to retrieve, interpret and
   display Hypertext Markup Language (HTML).  These products are often a
   part of a complete Internet Printing system because they are often

   used as a means of obtaining the status of or more information about
   the printing system; however, they may not be present in all
   implementations.

   Throughout this document, 'printer' shall be interpreted to include
   any device which is capable of marking on a piece of media using any
   available technology.  These design goals do not include support for
   multi-tiered printing solutions involving servers (single or
   multiple) logically in front of the actual printing device yet all
   such configurations shall be supported but shall appear to the end-
   user as only a single device.

   Throughout this document 'driver' refers to the code installed in
   some client operating system to generate the print data stream for
   the intended printer. Some computing environments may not include a
   separate printer driver.  Rather, the generation of the proper print
   data stream is accomplished in an application on that computer. How
   such a computer environment or application is updated to support a
   new printer now made available using IPP is outside the scope of IPP.
   The actual details for installing a printer driver are operating
   system dependent and are also outside the scope of IPP. See also
   section 4.1 (SECURITY CONSIDERATIONS) for security implications of
   driver download and installation.

   The IPP protocol will support the following physical configurations:

   - An IPP client talking to an IPP Printer object imbedded in a
     single, physical output device.
   - An IPP Client talking to a server containing one or more IPP
     Printer objects. Each Printer object is associated with exactly one
     physical output device supported by the server. The protocol
     between the server and the output devices is undefined.
   - An IPP Client talking to an IPP Printer object in a server. The
     Printer object is associated with one or more physical output
     devices, but the client only sees the Printer object, which is an
     abstraction and represents all of the associated physical output
     devices. The protocol between the server and the physical output
     devices is undefined.

   Throughout this document, certain design goals will be identified as
   not being a part of version 1.0 (or V1.0) of the protocol or as being
   satisfied by means outside of IPP.  IPP is assumed to be one part, an
   enabler, of a complete Internet Printing solution.  For example
   printer instance creation is not performed by but is enabled by the
   protocol.  Globally, none of the operator or administrators wants and
   needs are included in the design goals for version 1.0.  Some of the
   end-user wants and needs may also be excluded from version 1.0 and
   will be so noted in the description of them.  Subsequent versions of

   the protocol (e.g. V2.0) may include support for these initially
   excluded wants and needs.

3. DESIGN GOALS

   The next three sections identify the design goals for an Internet
   printing protocol from three roles assumed by humans: end-user,
   operator, and administrator.  The goals defined here are only those
   that need to be addressed by an Internet printing protocol.  Other
   wants and needs, such as that the operator needs physical access to
   the printer (e.g. to be able to load paper or clear jams) are not
   covered by this document.  Section 5 contains scenarios which provide
   more detailed examples of the entire process including discovery,
   status, printing and end-of-job reporting.

3.1. END-USER

   An end-user of a printer accepting jobs through the Internet is one
   of the roles in which humans act.  The end-user is the person that
   will submit a job to be printed on the printer.

   The wants and needs of the end-user are broken down into six
   categories: finding/locating a printer, creating a local instance of
   a printer, viewing printer status, viewing printer capabilities,
   submitting a print job, viewing print job status, altering the
   attributes of a print job.

3.1.1. Finding or locating a printer.

   End-users want to be able to find and locate printers to which they
   are authorized to print.  They want to be able to perform this
   function using a standard WEB browser or other application.  Multiple
   criteria can be applied to find the printers needed.  These criteria
   include but are not limited to:

   - by name (Printer 1, Joes-color-printer, etc.)
   - by geographic location (bldg 1, Kentucky, etc.)
   - by capability or attribute (color, duplex, legal paper, etc.)

   Additionally, while it is outside of scope of IPP, end-users want to
   be able to limit the scope of their searching to:

   - inside a functional sub-domain
   - include only a particular domain (lexmark.com)
   - exclude specified domains

   While an Internet printing protocol may not of itself include this
   function, IPP must define and enable a directory schema which will
   provide the necessary information for a directory service
   implementation to consistently represent printers by their IPP
   attributes.

3.1.2. Create an instance of the printer.

   After finding the desired printer, an end-user needs to be able to
   create a local instance of that printer within the end-user operating
   system or desktop.  This local instance will vary depending upon the
   printing paradigm of the operating system.  For example, some UNIX
   users will only want a queue or a reference to a remote printer
   created on their machine while other UNIX users and Windows NT users
   will want the queue and also the necessary icons and registry entries
   to be created and initialized.  Where required, drivers may need to
   be downloaded from some repository and installed on the computer.
   All necessary decompressing, unpacking, and other installation
   actions should occur without end-user interaction or intervention
   excepting initial approval by the end-user.  Once the local instance
   of the printer has been installed, it shall appear to the end-user of
   the operating system and to the applications running there as any
   other printer (local, local area network connected, or network
   operating system connected) on the end-user desktop or environment.
   IPP's role in this goal is simply to enable the creation of the
   printer instance providing information such as where to locate a
   printer driver for this printer, as an attribute of an IPP Printer.

3.1.3. Viewing the status and capabilities of a printer.

   Before using a selected printer or, in fact at any time, the end-user
   needs the ability to verify the characteristics and status of both
   printers and jobs queued for that printer.  When checking the
   characteristics of a printer, the end-user typically wants to be able
   to determine the capability of the device, e.g.:

   - supported media, commonly paper, by size and type
   - paper handling capability, e.g. duplex, collating, finishing
   - color capability

   When checking the status of the printer and its print jobs, the end-
   user typically wants to be able to determine:

   - is the printer on-line?
   - what are the defaults to be used for printing?
   - how many jobs are queued for the printer?
   - how are job priorities assigned? (outside the scope of IPP)

3.1.4. Submitting a print job.

   Once the desired printer has been located and installed, the end-user
   wants to print to that printer from normal applications using
   standard methods.  These normal applications include such programs as
   word processors, spreadsheets, data-base applications, WEB browsers,
   production printing applications, etc.  Additionally, the end-user
   may want to print a file already existing on the end-user's computer
   -- "simple push".  In addition to printing from an application and
   simple push, the end-user needs to have the ability to submit a print
   job by reference.  Printing by reference is defined to mean as
   submitting a job by providing a reference to an existing document.
   The reference, a URI, will be resolved before the actual print
   process occurs.  Submitting a job by reference relieves the user from
   downloading the document from the remote server and then sending it
   via IPP to the printer.  This saves both time and network bandwidth.

   Some means shall be provided to determine if the format of a job
   matches the capability of the printer.  This can be done by one of
   the following (all of which are outside of scope of the IPP
   protocol):

      - the end-user selects the correct printer driver
      - the printer automatically selects the proper interpreter
      - the end-user uses some other manual procedure.

   A standard action shall be defined should the job's requirements not
   match the capabilities of the printer.

   Because the end-user does not want to know the details of the
   underlying printing process, the protocol must support job-to-printer
   capability matching (all implementations are not necessarily required
   to implement this function.)  This matching capability requires
   knowing both the printer's capabilities and attributes and those
   capabilities and attributes required by the job.  Actions taken when
   a print job requires capabilities or attributes that are not
   available on the printer vary and can include but are not limited to:

   - rejecting the print job
   - redirecting the print job to another printer (Not in V1.0)
   - printing the job, accepting differences in the appearance

   Print jobs will also be submitted by background or batch applications
   without human intervention.

   End-users need the ability to set certain print job parameters at the
   time the job is submitted.  These parameters include but are not
   limited to:

   - number of copies
   - single or two sided printing
   - finishing
   - job priority

3.1.5. Viewing the status of a submitted print job.

   After a job has been submitted to a printer, the end-user needs a way
   to view the status of that job (i.e. job waiting, job printing, job
   done) and to determine where the job is in the print queue.

   In addition to the need to inquire about the status of a print job,
   automatic notification of the completion of that job is also
   required.

   Notification means are not defined by the protocol but the protocol
   must provide a means of enabling and disabling the notification.

3.1.6. Canceling a Print Job

   While a job is waiting to be printed or has been started but not yet
   completed, the original creator/submitter of the print job (i.e. the
   end-user) shall be able to cancel the job entirely (job is waiting)
   or the remaining portion of it (job is printing.)  Altering the print
   job itself is not a V1.0 design goal.

3.2. OPERATOR (NOT REQUIRED FOR V1.0)

   An operator of a printer accepting jobs through the Internet is one
   of the roles in which humans act.  The operator has the
   responsibility of monitoring the status of the printer as well as
   managing and controlling the jobs at the device.  These
   responsibilities include but are not limited to the replenishing of
   supplies (ink, toner, paper, etc.), the clearing of minor errors
   (paper jams, etc.) and the re-prioritization of end-user jobs.
   Operator wants and needs will not be addressed by V1.0 of the
   protocol.

   The wants and needs of the operator include all those of the end-user
   but may include additional privileges.  For example, an operator may
   be able to view all print jobs on a printer while the end-user might
   only be able to see his own jobs.

3.2.1. Alerting.

   One of the required operator functions is having the ability to
   discover or to be alerted to changes in the status of a printer
   particularly those changes that cause a printer to stop printing and

   to be able to correct those problems.  As such, an Internet printing
   protocol shall be able to alert a designated operator or operators to
   these conditions such as 'out of paper', 'out of ink', etc.
   Additionally. the operator shall be able to, asynchronous to other
   printer activity, inquire as to a printer's or a job's status.

3.2.2. Changing Print and Job Status.

   Another of the required operator functions is the ability to affect
   changes to printer and job status remotely.  For example, the
   operator will need to be able to re-prioritize or cancel any print
   jobs on a printer to which the operator has authority.

3.3. ADMINISTRATOR (NOT REQUIRED FOR V1.0)

   An administrator of a printer accepting jobs through the Internet is
   one of the roles in which humans act.  The administrator has the
   responsibility of creating the printer instances and controlling the
   authorization of other end-users and operators.  Administrator wants
   and needs will not be addressed by V1.0 of the protocol.

   The wants and needs of the administrator include all those of the
   end-user and, in some environments, some or all of those of the
   operator.  Minimally, the administrator must also have the tools,
   programs, utilities and supporting protocols available to be able to:

   - create an instance of a printer
   - create, edit and maintain the list of authorized end-users
   - create, edit and maintain the list of authorized operators
   - create, edit and maintain the list of authorized
     administrators
   - create, customize, change or otherwise alter the manner in
     which the status capabilities and other information about printers
     and jobs are presented
   - create, customize, or change other printer or job features
   - administrate billing or other charge-back mechanisms
   - create sets of defaults
   - create sets of capabilities

   The administrator must have the capability to perform all the above
   tasks locally or remotely to the printer.

4. OBJECTIVES OF THE PROTOCOL

   The protocol to be defined by an Internet printing working group will
   address the wants and needs of the end-user (V1.0).  It will not, at
   least initially, address the operator or administrator wants and
   needs (V2.0).

   The protocol defined shall be independent of the operating system of
   both the client and the server.  Generally, any platform capable of
   supporting a WEB Browser should be capable of being a client.
   Generally, any platform providing a WEB/HTTP server and printing
   services should be capable of being a server.  Usage of the WEB
   Browser and Server is not required for IPP; the operating system,
   operating system extensions or other applications may provide IPP
   functionality directly.

   In many environments such as Windows 95, Windows NT and OS/2, the
   print data is created and transmitted to the printer on the fly
   rather than being created, spooled and then transmitted to the
   printer (a typical UNIX method.)  The Internet Printing Protocol must
   properly handle either methodology and make this transparent to the
   end-user.

4.1. SECURITY CONSIDERATIONS

   It is required that the Internet Printing Protocol be able to operate
   within a secure environment. Wherever reasonable, IPP ought to make
   use of existing security protocols and services. IPP will not invent
   new security features when the design goals described in this
   document can be met by existing protocols and services. Examples of
   such services include Secure Socket Layer Version 3 (SSL3) [SSL] and
   HTTP Digest Access Authentication [RFC2069].  Note: SSL3 is not on
   the IETF standards track.

   Since we cannot anticipate the security levels or the specific
   threats that any given IPP print administrator may be concerned with,
   IPP must be capable of operating with different security mechanisms
   and policies as required by the individual installation. The initial
   security needs of IPP are derived from two primary considerations.
   First, the printing environments described in this document take into
   account that the client, the Printer, and the document to be printed
   may each exist in different security domains. When objects are in
   different security domains the design goals for authentication and
   message protection may be much stronger than when they are all in the
   same domain.

   Secondly, the sensitivity and value of the content being printed will
   vary from one instance of a print job to another. For example, a
   publicly available document does not need the same level of
   protection as a payroll document does.  Message protection design
   goals include data origin authentication, privacy, integrity, and
   non-repudiation.

   In many environments (e.g. Windows, OS/2) a printer driver may be
   needed to create the proper datastream for printer.  This document
   discusses downloading such a new driver from a variety of sources.
   Downloading and installing any software, including drivers) on a
   computer exposes that computer to a number of security risks
   including but not limited to:

      - defective software
      - malicious software (e.g. Trojan horses)
      - inappropriate software (i.e. software doing something
        deemed unreasonable by the user.)

   As such, proper security considerations and actions need to be taken
   by the user and/or a system administrator to prevent the compromising
   of the computer.  Administrators should configure downloading
   mechanism for printer drivers in such a way as to be able to verify
   the source of driver software and encrypt or otherwise protect that
   software during download.

   Examples including security considerations can be found in sections 5
   (IPP SCENARIOS) and 10 (APPENDIX - DETAILED SCENARIOS) later in this
   document.

4.2. INTERACTION WITH LPD (RFC1179)

   Many versions of UNIX and in fact other operating systems provide a
   means of printing as described in [RFC1179] (Line Printer Daemon
   Protocol.)  This document describes the file formats for the control
   and data files as well as the messages used by the protocol.  Because
   of the simplistic approach taken by this protocol, many manufacturers
   have include proprietary enhancements and extensions to 'lpd.'
   Because of this divergence and due to other design goals described in
   this document, there is no requirement for backward compatibility or
   interoperability with 'lpd'.  However, a mapping of LPD functionality
   and IPP functionality shall be provided so as to enable a gateway
   between LPD and IPP.

4.3. EXTENSIBILITY

   The Internet Printing Protocol shall be extensible by several means
   that facilitate interoperability and prevent implementation
   collisions:

      - by providing a process whereby implementers can submit proposals
      for registration of new attributes and new enumerated values for
      existing attributes.

         * that require review and approval.  The Internet Assigned
         Number Authority (IANA) will be the repository for such
         accepted registration proposals after review.

         * that do not require review and approval.  IANA will be the
         repository for such registrations.

      - by providing syntax in the protocol so that implementers may add
      private (i.e. unregistered) attributes and  enumerated attribute
      values.

      - by providing versioning and negotiation so as to enable future
      implementations of IPP to interoperate with implementations of
      version 1.0 of IPP.

4.4. FIREWALLS

   As stated in section 3 Design Goals, Internet printing shall, by
   definition, support printing from one enterprise to another.  As
   such, the Internet printing protocol must be capable of passing
   through firewalls and/or proxy servers (where enabled by the firewall
   administrator) preferably without modification to the existing
   firewall technology.

4.5. INTERNATIONALIZATION

   Users of Internet printing will come from all over the world.  As
   such, where appropriate, internationalization and localization will
   be enabled for the protocol.

5. IPP SCENARIOS

   Each of the scenarios in this section describes a specific IPP
   operation, such as submitting a print job. Section 10 contains
   several detailed flows for each scenario to provide additional
   detail.  The examples should not be considered exhaustive, but
   illustrative of the functions and features required in the protocol.
   Flows are intended to be protocol neutral. It is not assumed that all
   of the functions and features described in these scenarios will
   necessarily be supported directly by IPP or in version 1.0 of IPP.

   See the IPP Model and Semantics document for details on
   configurations of clients, servers and firewalls.

5.1. PRINTER DISCOVERY

   Client                                               Directory Service
   Service

    +----------------------------------------------------------- >
       give me information on printers with these characteristics

    < -----------------------------------------------------------+
        Information on Printers matching these characteristics

   The objective of printer discovery is to locate printers that meet
   the client's wants and needs. The Directory Service should provide
   enough information for the client to make an initial choice. The
   client may have to connect to each individual Printer offered to get
   more detail.  Not all information available from the Directory
   Service is obtained using IPP; some information may be
   administratively provided.

   The actual protocol used between client and Directory or Name Service
   is considered outside the scope of IPP. Printer Discover is included
   in the scenarios to provide design goals for the directory schema for
   IPP Printers and to further define Printer attributes.

   Characteristics that might be considered when locating a Printer
   include:

   - capabilities of the Printer, e.g. PDLs supported
   - physical location, e.g. in building 010
   - driver required and location
   - cost per page to print (outside the scope of IPP)
   - whether or not printer is access controlled
   - whether or not usage requires client authentication
   - whether or not Printer can be authenticated
   - whether or not payment is required for printing (outside the scope
     of IPP)
   - maximum job size (spool size) (outside the scope of IPP)
   - whether or not Printer support compression (outside the scope of
     IPP)
   - whether or not Printer supports encryption
   - administrative limits on this Printer
      - maximum number of copies per job
      - maximum number of pages per job

   Responses could additionally include:

   - how to get more information
      - web page
      - telephone number
      - help desk

5.2. DRIVER INSTALLATION

   Client                                               Printer

    +----------------------------------------------------------- >
       Where can I find a driver & software to install it?

    < -----------------------------------------------------------+
        URIs for drivers and install software

   Driver here refers to the code installed in some client operating
   system to generate the print data stream for the intended printer.
   The actual details for installing a printer driver are operating
   system dependent and are also outside the scope of IPP.  However, an
   IPP printer or a directory service advertising an IPP Printer should
   be capable of telling a client what drivers are available and/or
   required, where they can be found, and provide pointers to
   installation instructions, installation code or initialization
   strings required to install the driver.  See section 4.1 (SECURITY
   CONSIDERATIONS) for security implications of driver download and
   installation.

5.3. SUBMITTING A PRINT JOB

   Client                                               IPP Printer

    +----------------------------------------------------------- >
       Here is a Print Job
        - Job attributes
        - Print data

    < -----------------------------------------------------------+
        Response

   The protocol must support these sources of client data:

   - Print data is a file submitted with the job
   - Print data is generated on the fly by an application
   - Print data is a file referenced by a URI

   The protocol must handle overrun conditions in the printer and must
   support overlapped printing and downloading of the file in devices
   that are unable to spool files before printing them.

   Every print request will have a response. Responses will indicate
   success or failure of the request and provide information on failures
   when they occur. Responses would include things like:

   - Got the print job and queued it
   - Got the print job and am printing it
   - Got the print job, started to print it, but printing failed
      - why it failed (e.g. unrecoverable PostScript error)
      - state of the printer
      - how much printed
   - Got the print job but couldn't print it
      - why it can't be printed
      - state of the printer
   - Got the print job but don't know what to do with it
   - Didn't get a complete print job (e.g. communication failure)

5.4. GETTING STATUS/CAPABILITIES

   Client                                               IPP Printer

    +----------------------------------------------------------- >
       Get status and/or capabilities of Printer

    < -----------------------------------------------------------+
        Status/Capabilities

   Clients will need to get information about

   - Static capabilities of the device
   - Dynamic state of the Printer (e.g. out of paper)
   - State of a specific job owned by this client
   - State of all jobs owned by this client
      - queued
      - printing
      - completed

   - Job submission attributes supported/required
      - scheduling attributes (e.g. priority)
      - production attributes (e.g. number of copies)

5.5. ASYNCHRONOUS NOTIFICATION

   Client                                               IPP Printer

    +----------------------------------------------------------- >
       Use the following method to notify me of Printer events

                                 .
                                 .
                                 .
    < -----------------------------------------------------------+
        Asynchronous notification of Printer event

   Clients must be able to request asynchronous notification for Printer
   events such as

   - job completion
   - a fatal error that requires the job to be resubmitted
   - a condition that severely impacts a queued job for this client
      e.g. printer is out of paper

   Note: end-user notification is a V1.0 design goal while operator
   notification is for V2.0.

5.6. JOB CANCELING

   Client                                               IPP Printer

    +----------------------------------------------------------- >
       Cancel the named job as indicated

    < -----------------------------------------------------------+
        Response (did it or not)

   Similarly clients must be able to make changes to jobs which have
   been submitted and are queued for printing.  Changing of job
   attributes should also be supported.  Job modifications, holding and
   releasing of jobs are not included in the design goals for IPP v1.0.

6. SECURITY CONSIDERATIONS

   The security considerations for IPP are described in Section 4.1
   above.

7. REFERENCES

   [ipp-iig]  Hastings, T. and C. Manros, "Internet Printing
              Protocol/1.0: Implementer's Guide", Work in Progress.

   [RFC2569]  Herriot, R., Hastings, T., Jacobs, N. and J. Martin,
              "Mapping between LPD and IPP Protocols", RFC 2569, April
              1999.

   [RFC2566]  deBry, R., Hastings, T., Herriot, R., Isaacson, S. and P.
              Powell, "Internet Printing Protocol/1.0: Model and
              Semantics", RFC 2568, April 1999.

   [RFC2565]  Herriot, R., Butler, S., Moore, P. and R. Tuner, "Internet
              Printing Protocol/1.0: Encoding and Transport", RFC 2565,
              April 1999.

   [RFC2568]  Zilles, S., "Rationale for the Structure and Model and
              Protocol for the Internet Printing Protocol", RFC 2568,
              April 1999.

   [ISO10175] ISO/IEC 10175, Document Printing Application, June 1996.

   [RFC1179]  McLaughlin, L., "Line Printer Daemon Protocol" RFC 1179,
              August 1990.

   [SSL]      Netscape, The SSL Protocol, Version 3, (Text version
              3.02), November 1996.

8. ACKNOWLEDGMENTS

   This document draws heavily from preliminary work done by others
   especially in the Printer Working Group (PWG).  The author gratefully
   acknowledges the specific contributions of:

   Scott Isaacson                   Roger deBry
   Novell                           Utah Valley State College
   sisaacson@novell.com             debryro@uvsc.edu

   Carl-Uno Manros                  Robert Herriot
   Xerox                            Sun
   manros@cp10.es.xerox.com         Robert.Herrior@pahv.xerox.xom

   Tom Hastings                     Peter Zehler
   Xerox                            Xerox
   hastings@cp10.es.xerox.com       Peter.Zehler@usa.xerox.com

9. AUTHOR'S ADDRESS

   F.D. (Don) Wright
   Lexmark International
   C14/035-3
   740 New Circle Rd
   Lexington, KY  40550

   Phone: 606-232-4808
   Fax: 606-232-6740
   EMail: don@lexmark.com

10. APPENDIX - DETAILED SCENARIOS

   The following are more detailed scenarios illustrating how the
   Internet Printing Protocol is expected to be used as a part of a
   complete Internet Printing system.  Some parts of the scenarios
   include concepts, functions and information that may be outside of
   the scope of version 1.0 of IPP (e.g. cost per page, payments means
   available, etc.)  The information contained herein is meant to be
   generic.  There may not be an exact wording or terminology match
   between these scenarios and the implementation documents.

10.1. PRINTER DISCOVERY WITHIN AN ENTERPRISE

   A user wants to find a color Postscript printer in his/her enterprise
   which will print transparencies. The client, directory service, and
   printer are all behind the same corporate firewall. Because color
   foils are expensive, printers of this type are access controlled and
   require an account to be established so that printing can be billed
   back to the using department. Note the request to find a printer
   usable by Dept.  J15. Drivers for all supported printers are
   available from the server they are associated with. A help desk is
   provided for end user support.  The printer is unattended.

   Client                                  Directory Service

      +---------------------------------------------------------- >
        Find a printer with these characteristics
        - prints color, prints transparencies
        - prints Postscript
        - is in building 003
        - accessible by the client

      < ----------------------------------------------------------+
        Printer "Color-A"
        - prints color, prints transparencies
        - prints Postscript
        - in room H-6, building 003
        - driver ABC-Postscript-V1.3 required, here is URI
        - cost is $.45 per page for color transparencies
        - limit is 10 pages per job
        - authentication required to use printer
        - printer is unattended
        - help desk at x5001

         Printer "Color-B"
        - prints color, prints transparencies
        - prints Postscript
        - in room J-10, building 003

        - driver XYZ-Postscript-V2.4 required, here is URI
        - cost is $1.25 page for color transparencies
        - limit is 5 pages per job
        - authentication is required to use printer
        - printer is unattended
        - help desk at x5001

10.2. PRINTER DISCOVERY ACROSS ENTERPRISES

   A user in Company A wants to find a public printer in a business
   partner's enterprise (Company B) on which to print a purchase order.
   The client is behind one corporate firewall and the directory service
   and the printer are behind a different corporate firewall. Drivers
   for all supported printers are available from the server they are
   associated with. A web page is provided for end user support for
   public printers.

   Client                        Company B Directory Service

      +---------------------------------------------------------- >
        Find a printer with these characteristics
        - prints black and white
        - is in El Segundo, building A
        - is a public printer

      < ----------------------------------------------------------+
        Printer "Public-A"
        - prints black and white
        - prints Postscript
        - in El Segundo, room H-6, building A
        - driver ABC-Postscript-V1.3 required, here is URI
        - printer is public
        - help available at http://xerox/elSegundo/publicPrinters

         Printer "Public-B"
        - prints black and white
        - prints PCL/5e
        - is in El Segundo, room J-10, building A
        - driver XYZ-PCL-V2.4 required, here is URI
        - printer is public
        - help available at http://xerox/elSegundo/publicPrinters

10.3. PRINTER DISCOVERY ON THE INTERNET -LOGICAL OPERATIONS

   A student wants to print a paper on a printer at his neighborhood
   Ink-o's print shop. The report was written using Microsoft Word. The
   student is interested in the cost of printing since his budget is
   limited. Note the use of logical operators to find this information.

   Client                          Ink-o's Directory Service

      +---------------------------------------------------------- >
        Find a Printer with these characteristics
        - prints color or black and white
        - costs less than $.50 per page
        - tell me about resolution and marking technology

      < ----------------------------------------------------------+
        Printer "Color-A"
        - prints color
        - 600 dpi laser printer
        - prints Postscript
        - driver ABC-Postscript-V1.3 required, here is URI
        - cost is $.50 per page for color
        - payment required prior to submitting print job
        - here is URI for more information on Ink-o's

         Printer "Mono-B"
        - prints black and white
        - 300 dpi inkjet printer
        - prints Postscript
        - driver XYZ-Postscript-V2.4 required, here is URI
        - cost is $0.35 page for black and white
        - payment required prior to submitting print job
        - here is URI for more information on Ink-o's

10.4. PRINTER DISCOVERY ON THE INTERNET - AUTHENTICATION

   An executive in her hotel room is finishing an important presentation
   on her laptop computer. She connects to a local print shop through
   the web to get a copy of her charts printed for tomorrow's
   presentation.  She must find a print shop that is convenient to her
   hotel and can print color transparencies. She wants to be sure that
   the printer can be authenticated and can accept encrypted data.

   Client                         SirZippy Directory Service

      +---------------------------------------------------------- >
        Find a Printer with these characteristics
        - prints color transparencies
        - is in Boulder, Colorado
        - Printer can be authenticated
        - Printer supports encryption

        Tell me when you are open for business

      < ----------------------------------------------------------+
        Printer "Color-A"
        - prints color transparencies
        - prints Postscript
        - driver ABC-Postscript-V1.3 required, here is URI
        - payment required prior to submitting print job
        - Printer can be authenticated
        - Data can be encrypted
        - Located at 1670 Pearl Street, Boulder, CO
        - This Branch is open 24 hours a day

        Printer "Color-B"
        - prints color transparencies
        - prints Postscript
        - driver ABC-Postscript-V1.3 required, here is URI
        - payment required prior to submitting print job
        - Printer can be authenticated
        - Data can be encrypted
        - Located at 1220 Arapahoe, Boulder, CO
        - This Branch is open from 9:00 am to 6:30 pm

10.5. DRIVER DOWNLOAD

   An end user in an enterprise wants to print a lengthy report on a
   newly installed high speed PostScript printer. Since she will likely
   use this printer often, she would like to download a driver and
   install it on her workstation. She is running Windows 95.  Note:
   Driver download is not a V1.0 design goal.

   Client                                        IPP Printer

      +---------------------------------------------------------- >
        Tell me where to find print drivers for you

      < ----------------------------------------------------------+
        Driver install file is at
        http://www.ibm.com/drivers/NP12a/Win95

10.6. SUBMITTING A PRINT JOB AS A FILE

   An end-user wants to submit a print job. The print file already
   exists on his workstation. The client and printer are behind the same
   corporate firewall. The printer is available to anyone behind the
   firewall and no authorization or authentication is required. The data
   is pushed to the printer. The printer is capable of spooling the
   output. No errors occur.

   Client                                        IPP Printer

      +---------------------------------------------------------- >
        Here is a print job
        - job name = MyJob
        - notify me by email when done printing
        - print on iso-a4-white paper
        - print on both sides of the paper
        - return status of the printer in response
        - document is in Postscript format
        - here is the document to print

      < ----------------------------------------------------------+
        Print job accepted and spooled
        - job id = #12345
        - current state of print job = spooled
        - submission time = 02/12/97, 15:35
        - printer state = printing

10.7. SUBMITTING A PRINT JOB WITH TWO DOCUMENTS

   An end-user wants to submit a print job. The print file already
   exists on his workstation. The client and printer are behind the same
   corporate firewall. The printer is available to anyone behind the
   firewall and no authorization or authentication is required. The data
   is pushed to the printer. The job consists of two separate documents.
   The printer is capable of spooling the output. No errors occur.

   Client                                        IPP Printer

      +---------------------------------------------------------- >
        Here is a print job
        - job name = MyJob
        - notify me by email when done printing
        - print on iso-a4-white paper
        - print on both sides of the paper
        - return status of the printer in response

      < ----------------------------------------------------------+

        Print job accepted and spooled
        - job id = #12345
        - submission time = 02/12/97, 15:35
      +---------------------------------------------------------- >
        - here is the document to print

      < ----------------------------------------------------------+
        - OK

      +---------------------------------------------------------- >
        - here is the document to print, it is the last document.

      < ----------------------------------------------------------+
        - OK

10.8. SUBMITTING A PRINT JOB AS A FILE, PRINTING FAILS

   An end-user wants to submit a print job. The print file already
   exists on his workstation. The client and printer are behind the same
   corporate firewall. The printer is available to anyone behind the
   firewall and no authorization or authentication is required. The data
   is pushed to the printer. The printer is not capable of spooling the
   output so it begins printing while still receiving the file. An error
   occurs and the printer cannot complete printing (in this case the
   user requires A4 paper and that paper size is not available on the
   printer.)

   Client                                        IPP Printer

      +---------------------------------------------------------- >
        Here is a print job
        - job name = MyJob
        - notify me by email when done printing
        - print on iso-a4-white paper
        - print on both sides of the paper
        - return status of the printer in response
        - document is in Postscript format
        - here is the document to print

      < ----------------------------------------------------------+
             Print job accepted

        - printing failed
        - current state of print job = canceled (A4 not available)
        - submission time = 02/12/97, 15:35
        - printer state = ready

10.9. SUBMITTING A PRINT JOB WITH AUTHENTICATION, PRIVACY AND PAYMENT

   A traveling executive needs to print a set of transparencies for an
   important business meeting. The charts are in Lotus Freelance format
   on his notebook computer. He has located a SirZippy print shop near
   his hotel that will print color transparencies. Because the
   information on the charts is sensitive, he wants to be sure that his
   data is sent to the Printer in an encrypted format. He also wants to
   authenticate the Printer. The Printer also authenticates the user.
   Payment occurs across the Internet.

   Client                                               IPP Printer

      +---------------------------------------------------------- >
      < ----------------------------------------------------------+

        Mutual authentication and exchange of secret keys

      +---------------------------------------------------------- >
        Here is a print job (encrypted)
        - job name = MyJob
        - notify me by email when done printing
        - print on iso-a4-white paper
        - print on both sides of the paper
        - return status of the printer in response
        - tell me where to pick up output
        - document is in Postscript format
        - here is the document to print

      < ----------------------------------------------------------+
        Print job accepted and spooled (encrypted)
        - job id = #12345
        - current state of print job = spooled
        - submission time = 02/12/97, 15:35
        - printer state = printing
        - payment required to proceed with job
        - pick up at 230 East Main after 3:30 pm today

      +---------------------------------------------------------- >
      < ----------------------------------------------------------+
        Payment transaction

10.10. SUBMITTING A PRINT JOB WITH DECRYPTION ERROR

   A traveling executive needs to print a set of transparencies for an
   important business meeting. The charts are in Lotus Freelance format
   on his notebook computer. He has located a SirZippy print shop near
   his hotel that will print color transparencies. Because the
   information on the charts is sensitive, he wants to be sure that his
   data is sent to the printer in an encrypted format. He also wants to
   authenticate the printer. The printer also authenticates the user.
   Payment occurs across the Internet. An error occurs during
   decryption.

   Client                                        IPP Printer

      +---------------------------------------------------------- >
      < ----------------------------------------------------------+
        Mutual authentication and exchange of secret keys

      +---------------------------------------------------------- >
        Here is a print job (encrypted)
        - job name = MyJob
        - notify me by email when done printing
        - print on iso-a4-white paper
        - print on both sides of the paper
        - return status of the printer in response
        - tell me where to pick up output
        - document is in Postscript format
        - here is the document to print

      < ----------------------------------------------------------+
        Print job accepted and spooled (encrypted)
        - job id = #12345
        - current state of print job = spooled
        - submission time = 02/12/97, 15:35
        - printer state = printing
        - payment required to proceed with job
        - pick up at 230 East Main after 3:30 pm today

      +---------------------------------------------------------- >
      < ----------------------------------------------------------+
        Payment transaction
        .
        .
        .
      < ----------------------------------------------------------+
        Asynchronous response (email in this case)
        - decryption failed on job #12345

        - no pages printed
        - current state of job = aborted

10.11. SUBMITTING A PRINT JOB WITH AUTHENTICATION

   An end-user wants to submit a print job. The print file already
   exists on his workstation. The client and printer are behind the same
   corporate firewall. The printer is available to anyone behind the
   firewall but authentication and authorization is required.
   Authorization takes place using the authenticated end-user's name.
   The data is pushed to the printer. The printer is capable of spooling
   the output.

   Client                                        IPP Printer

      +---------------------------------------------------------- >
      < ----------------------------------------------------------+
        Authentication

        Note: An authentication failure would end the transaction at
                  this point.

      +---------------------------------------------------------- >
        Here is a print job
        - job name = MyJob
        - notify me by email when done printing
        - print on iso-a4-white paper
        - print on both sides of the paper
        - return status of the printer in response
        - tell me where to pick up output
        - document is in Postscript format
        - here is the document to print

      < ----------------------------------------------------------+
        Print job accepted and spooled
        - job id = #12345
        - current state of print job = spooled
        - submission time = 02/12/97, 15:35
        - printer state = printing

10.12. SUBMITTING A PRINT JOB GENERATED DYNAMICALLY

   An end-user wants to submit a print job. The print data is generated
   dynamically and is being transmitted by a printer driver on the
   client workstation as available. The client and printer are behind
   the same corporate firewall. The printer is available to anyone
   behind the firewall and no authentication and authorization is
   required. The data is pushed to the printer. The printer is capable
   of spooling the output.  No error occurs.

   Client                                        IPP Printer

      +---------------------------------------------------------- >
        Here is a print job
        - job name = MyJob
        - notify me by email when done printing
        - print on iso-a4-white paper
        - print on both sides of the paper
        - return status of the printer in response
        - document is in Postscript format
        - here is the print job

      < ----------------------------------------------------------+
        Print data accepted and spooling started
        - job id = #12345
        - current job state = spooled
        - submission time = 02/12/97, 15:35
        - printer state = printing

10.13. SUBMITTING A PRINT JOB WITH A PRINTER JAM - CANCELED

   An end-user wants to submit a print job. The print data is generated
   dynamically and is being transmitted by a printer driver on the
   client workstation as available. The client and printer are behind
   the same corporate firewall. The printer is available to anyone
   behind the firewall and no authentication and authorization is
   required. The data is pushed to the printer. The printer is not
   capable of spooling the output. The printer jams notifies the user
   and the user chooses to cancel the job.

   Client                                            IPP Printer
      +---------------------------------------------------------- >
        Here is a print job
        - job name = MyJob
        - notify me by email when done printing
        - print on iso-a4-white paper
        - print on both sides of the paper

        - return status of the printer in response
        - document is in Postscript format
        - here is the document to print

      < ----------------------------------------------------------+
        Print data accepted and printing started
        - job id = #12345

      +---------------------------------------------------------- >
        - What is the status of print job #12345?

      < --------------------------------------------------------- +
        - Job #12345 accepted but printer jammed, cannot continue

      +---------------------------------------------------------- >
        - Cancel job #12345

      * Printer flushes remaining data
      < ----------------------------------------------------------+
         Print job terminated
        - current job state = canceled
        - submission time = 02/12/97, 15:35
        - printer state = jammed

10.14. SUBMITTING A PRINT JOB WITH A PRINTER JAM - RECOVERED

   An end-user wants to submit a print job. The print data is generated
   dynamically and is being transmitted by a printer driver on the
   client workstation as available. The client and printer are behind
   the same corporate firewall. The printer is available to anyone
   behind the firewall and no authentication and authorization is
   required. The data is pushed to the printer. The printer is not
   capable of spooling the output. The printer jams, notifies the user
   and the user clears the jam and elects to continue.

   Client                                        IPP Printer

      +---------------------------------------------------------- >
        Here is a print job
        - job name = MyJob
        - notify me by email when done printing
        - print on iso-a4-white paper
        - print on both sides of the paper
        - return status of the printer in response
        - document is in Postscript format
        - here is the document to print

      < ----------------------------------------------------------+

        Print data accepted and printing started
        - job id = #12345

      < --------------------------------------------------------- +
        - Notification: printer jammed, cannot continue

      * Jam is clear by human intervention, printing continues

      +---------------------------------------------------------- >
         Here is the last part of the document to print

      < ----------------------------------------------------------+
         Print job received
        - current job state = printing
        - submission time = 02/12/97, 15:35
        - printer state = printing

10.15. SUBMITTING A PRINT JOB WITH SERVER PULL

   An end-user wants to submit a print job. The print data is in a file
   and is publicly available. It is pulled by the printer. The client
   and printer are behind the same corporate firewall. The printer is
   available to anyone behind the firewall and no authentication and
   authorization is required. The printer is capable of spooling the
   output. Printing may start before the entire job has been pulled.

   Client                                        IPP Printer

      +---------------------------------------------------------- >
        Here is a print job

        - job name = MyJob
        - notify me by email when done printing
        - print on iso-a4-white paper
        - print on both sides of the paper
        - return status of the printer in response
        - here is a reference to the data to be printed

      < ----------------------------------------------------------+
        Print data accepted and printing started
        - job id = #12345
        - current state of job = spooled
        - submission time = 02/12/97, 13:15
        - printer state = printing

        .
        .
       < ----------------------------------------------------------+

        Get the file to be printed

       +---------------------------------------------------------- >
        Here it is

        Note: Failure to find the file, would end the transaction
                  with an error at this point and an asynchronous
                  notification would be send to the Client.

       < ----------------------------------------------------------+
         Data received

10.16. SUBMITTING A PRINT JOB WITH REFERENCED RESOURCES

   An end-user wants to submit a print job.  Part of the print data is
   on a file on the user's workstation. It is pushed by the client, but
   the print job requires some resource not included in the print file.
   The client and printer are behind the same corporate firewall. The
   printer is available to anyone behind the firewall and no
   authentication and authorization is required. The printer is capable
   of spooling the output. No errors occur.

   Client                                        IPP Printer

      +---------------------------------------------------------- >
        Here is a print job
        - job name = MyJob
        - notify me by email when done printing
        - print on iso-a4-white paper
        - print on both sides of the paper
        - return status of the printer in response

      < ----------------------------------------------------------+
        Print job accepted and spooled
        - job id = #12345
        - submission time = 02/12/97, 15:35

      +---------------------------------------------------------- >
        - here is the document to print

      < ----------------------------------------------------------+
        - OK

      +---------------------------------------------------------- >
        - here is the URI to print, it is the last document.

      < ----------------------------------------------------------+
        - OK

       < ----------------------------------------------------------+
         Get the external resource

       +---------------------------------------------------------- >
         Here it is

10.17. GETTING CAPABILITIES

10.17.1. Submission Attributes

   An end-user wants to get the production and scheduling attributes
   that are supported or required when submitting jobs to this printer.
   The client will use these attributes when forming the subsequent
   print request.

   Client                                        IPP Printer
      +---------------------------------------------------------- >
        I'm going to submit a Postscript job
        give me your job submission attributes

      < ----------------------------------------------------------+
        Postscript production attributes for this Printer are:
        - medium-select = us-letter-white, us-legal-white
           - default is us-letter-white
           -   copies = 1,2,3,4,5
           - default is 1
                - print-quality = draft, normal, high
           - default is draft
                - sides = 1-sided, 2-sided-long-edge
           - default is 2-sided-long-edge
        - Job scheduling attributes for this Printer are:
             - job-priority = 1,2,3
           - default = 3

10.17.2. Printer Capabilities

   An end-user wants to determine the resolution, marking technology,
   and PDLs supported by the printer.

   Client                                        IPP Printer
      +---------------------------------------------------------- >
        Please tell me the
        - resolution of the printer
        - the marking technology of the printer
        - PDLs supported
      < ----------------------------------------------------------+
        Printer resolution  = 600 dpi
        Marking Technology = laser

        PDLs supported = Postscript level 2, PCL/6

10.18. GETTING STATUS

10.18.1. Printer State/Status

   An end-user wants to determine the state or status of the printer.

   Client                                        IPP Printer

      +---------------------------------------------------------- >
        What is the state of the printer?

      < ----------------------------------------------------------+
        Printer state = out-of-paper

10.18.2. Job Status

   An end user wants to get the status of a job he has submitted.

   Client                                        IPP Printer

      +---------------------------------------------------------- >
        Please tell me the status of job #12345

      < ----------------------------------------------------------+
        Job #12345 is queued
        it is number 3 in the queue
        printer state = printing

10.18.3. Status of All My Jobs

   An end user wants to get a list of all of the jobs he has submitted
   to this Printer.

   Client                                        IPP Printer

      +---------------------------------------------------------- >
        Please tell me the status of my jobs

      < ----------------------------------------------------------+
        Job #00012 is complete
        Printed at 12:35 on 01/23/97

        Job #09876 is printing

        Job #12345 is queued
        it is number 3 in the queue

        Job #34567 is queued
        it is number 7 in the queue

10.19. ASYNCHRONOUS NOTIFICATION

10.19.1. Job Completion

   An end-user wants to get notification of events that affect his print
   jobs. Print job completes without error.

   Client                                        IPP Printer

      < ----------------------------------------------------------+
        Print job #123 completed

10.19.2. Job Complete with Data

   An end-user wants to get notification of events that affect his print
   jobs. Print job completes, users asked for all end of job
   information.

   Client                                        IPP Printer

      < ----------------------------------------------------------+
        Print job #123 completed
        - total pages printed = 15
        - number of copies printed = 3
        - total cost to print = $7.45
        - pick up copies in room H-6, building 005

10.19.3. Print Job Fails

   An end-user wants to get notification of events that affect his print
   jobs. Print job fails. Printer is unattended.

   Client                                        IPP Printer

      < ----------------------------------------------------------+
        Print job #123 failed
        - total pages printed = 15
        - number of pages submitted = 25
        - printer-state = jammed

10.20. CANCEL A JOB

   The end-user submits a print job and later decides to cancel it.

   Client                                        IPP Printer

      +---------------------------------------------------------- >
      < ----------------------------------------------------------+
        Authentication.

      +---------------------------------------------------------- >
        Cancel job #1234

      < ----------------------------------------------------------+
        Job #1234 Canceled

10.21. END TO END SCENARIO - WITHIN AN ENTERPRISE

   An office worker prints on shared departmental printers. All printers
   in the office are public, that is, no authentication or authorization
   is required. Printers are protected from external access by a
   firewall. No billing or accounting is required. Most printing is done
   from desktop applications. A help desk is provided for printing
   problems. Standard operating systems and applications are used.
   Drivers are available, but are installed manually by support
   personnel. This scenario assumes that drivers have been installed and
   that drivers are not IPP aware, that is, they cannot communicate
   across an IPP connection to obtain status and capabilities. IPP
   printers appear in application pull-down menus.  Printer
   configuration data is hard wired into the driver.

   End-user selects print from the application pull down menu. An IPP
   printer is selected from the list of Printers offered

   The driver puts up a dialogue with hard-wired set of options for this
   printer. The end-user makes choices and submits job.

   Client                                        IPP Printer
      +---------------------------------------------------------- >
        Here is a print job
        - job-name = memo-to-boss
        - notify me by email when job is complete
        - print on us-letter-white paper
        - print 1 copy
        - print at normal quality
        - print on 1 side

        - give me the state of the printer in response

   The driver generates the print data and passes it to the IPP driver a
   piece at a time as it is generated.

      +---------------------------------------------------------- >
        Here is the print data

      < ----------------------------------------------------------+
        Print data received, file is spooled
        - printer state = printing
        - time submitted = 2/12/97, 15:35
        - current job state = spooled

   Client adds this job to list of current jobs. List of jobs and state
   of each is available on a pull-down menu on the client.

   End-user selects job #1234 from list and clicks on it to see its
   status.

      +---------------------------------------------------------- >
        Give me the state of job #1234
        and the state of the Printer

      < ----------------------------------------------------------+
        Job #1234 state = spooled
        - it is number 3 in the queue
        - printer state = printing

   The job completes without error

      < ----------------------------------------------------------+
        Job #1234 completed
        12 of 12 pages printed

10.22. END TO END SCENARIO - ACROSS ENTERPRISES

   An office worker in Company A needs to print an office document on a
   "public" printer at Company B, a business partner. Both companies
   have corporate firewalls so the print request must flow out of A's
   firewall and into B's firewall. The office worker can look at public
   printers in Company B's directory service. The document is generated
   by a desktop application. Since the printer is "public" no
   authentication or authorization is required.  A driver is downloaded.
   The driver is IPP aware, that is, it can communicate dynamically
   through the IPP protocol layer to obtain information about the
   printer.

   Client                      Company B's Directory Service

   End user connects to B's Directory service

      +---------------------------------------------------------- >
        Find a Printer with these characteristics
        - public (no authorization or authentication required)
        - is in Lexington, building 004
        - prints black and white

      < ----------------------------------------------------------+
        Printer "Public-A"
        - http://www.lexmark.com/pubprinter/a

        Printer "Public-B"
        - http://www.lexmark.com/pubprinter/b

   End user selects Public-A

   Client                                           Public-A

      +---------------------------------------------------------- >
        Where can I find a driver for you?

      < ----------------------------------------------------------+
        Drivers at http://www.lexmark.com/pubprinters/a/os245

   End user gets driver and installs it on his PC.

   End-user selects print from the application pull down menu. "Public-
   A" is selected from the list of Printers offered

      +---------------------------------------------------------- >
        I'm going to submit a print job
        give me your job submission attributes

      < ----------------------------------------------------------+

        Production attributes for this Printer are:
        - medium-select = us-letter-white, us-legal-white
           - default is us-letter-white
           -   copies = 1,2,3,4,5
           - default is 1
                - print-quality = draft, normal, high
           - default is draft
                - sides = 1-sided, 2-sided-long-edge
           - default is 2-sided-long-edge

        Job scheduling attributes for this Printer are:
        - job-priority = 1,2,3
           default = 3

   Driver puts up dialogue with available options and fills in the
   defaults.

   End-user makes choices and submits job

      +---------------------------------------------------------- >
        Here is a print job
        - job-name = memo-to-Don-Wright
        - notify me by email when job is complete
        - print on us-letter-white paper
        - print 1 copy
        - print at normal quality
        - print on 1 side
        - give me the state of the printer in response

   The driver generates the print data and passes it to the IPP driver a
   piece at a time.

      +---------------------------------------------------------- >
        Here is the print data

      < ----------------------------------------------------------+
        Print data received, and spooling started
        print job id = #1234

        Print data received, file is spooled

        - printer state = printing
        - time submitted = 2/12/97, 15:35
        - current job state = spooled

   Client adds this job to list of current jobs.  List of jobs and state
   of each is available on a pull-down menu on the client.

   End-user selects job #1234 from list and clicks on it to see its
   status.

      +---------------------------------------------------------- >
        Give me the state of job #1234
        and the state of the Printer

      < ----------------------------------------------------------+
        Job #1234 state = spooled

        - it is number 3 in the queue
        - printer state = printing

       * The job completes without error
      < ----------------------------------------------------------+
        Job #1234 completed
        12 of 12 pages printed

10.23. END TO END SCENARIO - ON THE INTERNET

   An executive in her hotel room is finishing an important presentation
   on her laptop computer. She connects to a local print shop through
   the web to get a copy of her charts printed for tomorrow's
   presentation.  She must find a print shop that is convenient and can
   print color transparencies. She must download and temporarily install
   a driver in order to generate the PDL required by the print shop.
   Mutual authentication is required by the print shop and payment must
   be made in advance. The job is encrypted on the wire to prevent
   eavesdropping.

   End-user completes presentation. She goes to the web and connects to
   the SirZippy home page.

      Client                      SirZippy Directory Service
      +---------------------------------------------------------- >

        Find me a printer with these characteristics
        - Near Market Street in San Jose
        - Prints color transparencies
        - drivers can be downloaded
        - supports privacy (encryption)
        -

   Available Printers matching these characteristics are looked up in the
   Directory Service

      < ----------------------------------------------------------+

        Printer "Color-A"
        - located at 123 First Street in San Jose
        - URI is http://www.SirZippy.com/FirstStreet/Color-A
        - prints color transparencies
        - 600 dpi laser
        - driver ABC-Postscript-V1.3 available at this URI
        - cost = $.75 per page
        - authentication required to use printer
        - payment required prior to printing

        Printer "Color-B"
        - located at 67 San Carlos Street, San Jose
        - URI is http://www.SirZippy.com/SanCarlos/Color-B
        - prints color transparencies
        - 1200 dpi laser
        - driver XYZ-PostScript-V4.3 available at this URI
        - cost = $1.25 per page
        - authentication required to use printer
        - payment required prior to printing
        - more information at this URI

   The user decides to use the first printer because it is closer. She
   connects to the URI given to get a driver.

   Client                                         Driver URI

      +---------------------------------------------------------- >
        I need a driver for "Color-A"

      < ----------------------------------------------------------+
         Driver installer is at http://www.xerox.com/prtdrvrs

        Driver is installed

        User connects to
        "Color-A"

   Client                              IPP Printer "Color-A"

      +---------------------------------------------------------- >
      < ----------------------------------------------------------+
        Mutual authentication and exchange of secret keys

      +---------------------------------------------------------- >
        I'm going to submit a print job
        give me your job submission attributes

      < ----------------------------------------------------------+
        Production attributes for this Printer are:
        - medium-select = us-letter-white, us-legal-white
             - default is us-letter-white
        - copies = 1,2,3,4,5
             - default is 1
        - print-quality = draft, normal, high
             - default is draft
        - sides = 1-sided, 2-sided-long-edge
             - default is 2-sided-long-edge

        Job scheduling attributes for this Printer are:
        - job-priority = 1,2,3
           default = 3

   Driver puts up dialogue with available options and fills in the
   defaults.

   End-user makes choices and submits job

      +---------------------------------------------------------- >
         Here is a print job

        - job-name = presentation
        - notify me by email when job is complete
        - print on us-letter-transparency
        - print 1 copy
        - print at high quality
        - print by 9:00 am tomorrow morning
        - give me the state of the printer in response

   The driver generates the print data and passes it to the IPP  driver a
   piece at a time.

      +---------------------------------------------------------- >
       Here is the print data

       < ---------------------------------------------------------+
       Print data received, and spooling started
       print job id = #1234

       Print data received, file is spooled
        - printer state = printing
        - time submitted = 2/12/97, 15:35
        - current job state = held, waiting for payment

      +---------------------------------------------------------- >
      < ----------------------------------------------------------+
        Payment transaction

      < ----------------------------------------------------------+
        Job is scheduled to print, pick up after 9:00am tomorrow
        Thank you for using SirZippy

11.  Full Copyright Statement

   Copyright (C) The Internet Society (1999).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

 

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