Internet Printing Protocol WG Carl Kugler
INTERNET-DRAFT H. Lewis
<draft-ietf-ipp-ops-admin-req-01.txt> IBM Corporation
[Target Category: Informational] T. Hastings (editor)
Expires: January 17, 2002 Xerox Corporation
July 17, 2001
Internet Printing Protocol (IPP):
Requirements for Job, Printer, and Device Administrative Operations
Copyright (C) The Internet Society (2001). All Rights Reserved.
Status of this Memo
This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of [rfc2026]. Internet-Drafts are working
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Abstract
This document specifies the requirements and use cases for some optional
administrative operations for use with the Internet Printing
Protocol/1.0 (IPP) [RFC2565, RFC2566] and IPP/1.1 [RFC2911, RFC2910].
Some of these administrative operations operate on the IPP Job and
Printer objects. The remaining operations operate on a new Device
object that more closely models a single output device (see [RFC2911]).
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Table of Contents
1 Introduction.....................................................3
2 Terminology......................................................3
3 Requirements and Use Cases.......................................4
4 IANA Considerations.............................................11
5 Internationalization Considerations.............................11
6 Security Considerations.........................................11
7 Author's Addresses..............................................11
8 References......................................................12
9 Appendix A: Description of base IPP documents...................13
10 Appendix B: Full Copyright Statement...........................14
List of Tables
Table 1 - List of Printer Operations and corresponding Device
Operations ....................................................10
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1 Introduction
The Internet Printing Protocol (IPP) is an application level protocol
that can be used for distributed printing using Internet tools and
technologies. IPP version 1.1 ([RFC2911, RFC2910]) focuses on end user
functionality with a few administrative operations included (for a
description of the base IPP documents, see section 9). .This document
defines the requirements and use cases for additional optional end user,
operator, and administrator operations used to control Job objects,
Printer objects (see [RFC2911]) and a new Device object. The new Device
object more closely models a single output device and has no notion of a
job, while the Printer object models a print service which understands
jobs and may represent one or more output devices.
The scope of IPP is characterized in RFC 2526 [RFC2526] "Design Goals
for an Internet Printing Protocol". It is not the intent of this
document to revise or clarify this scope or conjecture as to the degree
of industry adoption or trends related to IPP within printing systems.
It is the intent of this document to extend the original set of
operations - in a similar fashion to the Set1 extensions which referred
to IPP/1.0 and were later incorporated into IPP/1.1.
2 Terminology
This section defines terminology used throughout this document and the
corresponding documents that define the Administrative operations on
Job, Printer, and Device objects.
This document uses terms such as "client", "Printer", "Job",
"attributes", "keywords", and "support". These terms have special
meaning and are defined in the model terminology [RFC2911] section 12.2.
In addition, the following capitalized terms are defined:
IPP Printer object (or Printer for short) - a software abstraction
defined by [RFC2911].
Printer Operation - an operation whose target is an IPP Printer
object and whose effect is on the Printer object.
Output Device - the physical imaging mechanism that an IPP Printer
controls. Note: while this term is capitalized in this
specification (but not in [RFC2911]), there is no formal object
called an Output Device.
Device Operation - an operation whose target is an IPP Printer object
and whose defined effect is on an Output Device.
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Output Device Fan-Out - a configuration in which an IPP Printer
controls more that one output-device.
Printer fan-out - a configuration in which an IPP Printer object
controls more than one Subordinate IPP Printer object.
Printer fan-in - a configuration in which an IPP Printer object is
controlled by more than one IPP Printer object.
Subordinate Printer - an IPP Printer object that is controlled by
another IPP Printer object. Such a Subordinate Printer may have
one or more Subordinate Printers.
Leaf Printer - a Subordinate Printer that has no Subordinate
Printers.
Non-Leaf Printer - an IPP Printer object that has one or more
Subordinate Printers.
Chained Printer - a Non-Leaf Printer that has exactly one Subordinate
Printer.
Job Creation operations - IPP operations that create a Job object:
Print-Job, Print-URI, and Create-Job.
3 Requirements and Use Cases
The Administrative operations for Job and Printer objects will be
defined in one document [ipp-admin-ops]. The Administrative operations
for Device objects will be defined in a separate document. The
requirements are presented here together to show the parallelism.
1. Have separate operations for affecting the IPP Printer versus
affecting the Output Device, so its clear what the intent of
each is and implementers can implement one or the other or both.
2. Support fan-out of Printer objects.
3. Support fan-out of Output Devices.
4. Support fan-in of Printer objects, as long as it doesn't make
the semantics more complicated when not supporting fan-in.
5. Support fan-in of output objects, as long as it doesn't make the
semantics more complicated when not supporting fan-in.
6. Instead of having operation attributes that alter the behavior
of the operation significantly, have separate operations, so
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that it is simple and clear to a client which semantics the
Printer is supporting (by querying the "operations-supported"
attribute) and it is simple to describe the capabilities of a
Printer implementation in written documentation (just list the
optional operations supported).
7. Need a Printer Operation to prevent a Printer object from
accepting new IPP jobs, but currently accepted jobs continue
unaffected to be scheduled and processed. Need a companion one
to restore the Printer object to accept new IPP jobs.
Usage: Operator is preparing to take the IPP Printer out of
service or to change the configuration of the IPP Printer.
Suggested name and operations: Disable-Printer and Enable-
Printer
8. Need a Device Operation to prevent an Output Device from
accepting any new jobs from any job submission protocol and a
companion one to restore the Output Device to accepting any
jobs.
Usage: Operator is preparing to take the Output Device out of
service.
Suggested name and operations: Disable-Device and Enable Device
9. Need a Printer Operation to stop the processing after the
current IPP job completes and not start processing any
additional IPP jobs (either by scheduling the jobs or sending
them to the Output Device), but continue to accept new IPP jobs.
Need a companion operation to start processing/sending IPP jobs
again.
Usage: Operator wants to gracefully stop the IPP Printer at the
next job boundary. The Pause-Printer-After-Current-Job operation
is also invoked implicitly by the Deactivate-Printer and the
Shutdown-Printer Operations.
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Suggested name and operations: Pause-Printer-After-Current-Job,
(IPP/1.1) Resume-Printer
10. Need a Device Operation to stop the processing the current job
"immediately", no matter what protocol. Its like the Pause
button on the Output Device. This operation is for emergencies.
The stop point depends on implementation, but can be mid page,
end of page, end of sheet, or after a few sheets for Output
Devices that can't stop that quickly. The paper path isn't run
out. Need a companion operation to start processing the current
any-protocol job without losing any thing.
Usage: Operator sees something bad about to happen, such as the
paper is about to jam, or the toner is running out, or the
device is overheating or wants to add more paper.
Suggested name and operations: Pause-Device-Now, Resume-Device
11. Need a Printer Operation to stop the processing of IPP jobs
after all of the currently accepted jobs have been processed,
but any newly accepted jobs go into the 'processing-held' state.
Usage: This allows an operator to reconfigure the Output Device
in order to let jobs that are held waiting for resources, such
as special media, to get a chance. Then the operator uses
another operation after reconfiguring. He repeats the two
operations to restore the Output Device to its normal media.
Suggested name and operations: Hold-New-Jobs, Release-Held-New-
Jobs
12. Need a Device Operation to stop the processing the current any-
protocol job at a convenient point, such as after the current
copy (or end of job if last or only copy). Need a companion
operation to start processing the current any-protocol job or
next job without losing any thing.
Usage: The operator wants to empty the output bin that is near
full. The paper path is run out.
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Suggested name and operations: Pause-Device-After-Current-Copy,
Resume-Device
13. Need a Device Operation that always pauses on a device-defined
boundary, no matter how many copies, in order to not break up a
job. Need a companion operation to start processing the current
any-protocol job or next job without losing any thing.
Usage: The operator wants to empty the output bin that is near
full, but he doesn't want to break up a job in case it has
multiple copies. The paper path is run out.
Suggested name and operations: Pause-Device-After-Current-Job,
Resume-Device
14. Need a Printer Operation that combines Disable-Printer, Pause-
Printer-After-Current-Job, and rejects all other Job, Printer,
and Device Operations, except Job and Printer queries, System
Administrator Set-Printer-Attributes, and the companion
operation to resume activity. In other words, this operation
makes the Printer a read-only object in a graceful manner for
end-users and the operator.
Usage: The administrator wants to reconfigure the Printer
object using the Set-Printer-Attributes operation without
disturbing the current in process work, but wants to make sure
that the operator isn't also trying to change the Printer object
as part of running the Printer.
Suggested name and operation: Deactivate-Printer, Activate-
Printer
15. Need a Device Operation that combines Disable-Device, Pause-
Device-After-Current-Job, and rejects all other Device
Operations, except Job and Printer queries and the companion
operation to resume activity. In other words, this operation
makes the Output Device a read-only object in a graceful manner.
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Usage: The field service person wants to open up the device
without disturbing the current in process work, perhaps to
replace staples, or replace the toner cartridge.
Suggested name and operation: Deactivate-Device, Activate-
Device
16. Need a Printer Operation to recover from the IPP Printer
software that has gotten confused (run out of heap memory or
gotten into a state that it doesn't seem to be able to get out
of). This is a condition that shouldn't happen, but does in
real life. Any volatile information is saved if possible before
the software is re-initialized. No companion operation is
needed to undo this. We don't want to go back to the "confused"
state :-).
Usage: The IPP Printer software has gotten confused or isn't
responding properly.
Suggested name and operation: Restart-Printer
17. Need a Device Operation to recover from the Output Device
hardware and software that has gotten confused (gotten into a
state that it doesn't seem to be able to get out of, run out of
heap memory, etc.). This is a condition that shouldn't happen,
but does in real life. This is the same and has the same
options as the Printer MIB reset. No companion operation is
needed to undo this. We don't want to go back to the "confused"
state :-).
Usage: The Output Device has gotten confused or need resetting
to some initial conditions.
Suggested name and operation: Reset-Device
18. Need a Printer Operation to put the IPP Printer object out of
business with no way in the protocol to bring that instantiation
back to life (but see Startup-Printer which brings up exactly
one new instantiation to life with the same URL). Any volatile
information is saved if possible.
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Usage: The Printer is being moved or the building's power is
being shut off.
Suggested name and operation: Shutdown-Printer
19. Need a Printer Operation to bring an IPP Printer to life when
there is an already running host.
Usage: After the host is started (by means outside the IPP
protocol), the operator is able to ask the host to bring up any
number of Printer objects (that the host has been configured in
some way) each with distinct URLs.
Suggested name and operation: Startup-Printer
20. Need a Device Operation to power off the Output Device after
writing out any software state. It is assumed that other
operations have more gracefully prepared the Output Device for
this drastic and immediate. There is no companion Device
Operation to bring the power back on.
Usage: The Output Device is going to be moved, the power in the
building is going to be shutoff, the repair man has arrived and
needs to take the Output Device apart.
Suggested name and operation: Power-Off-Device
21. Need a Device Operation to startup a powered-off device.
Usage: After a Power-Off-Device, if the device can be powered
back up (possibly by an intervening host that supports the
Device Operation).
Suggest name and operation: Power-On-Device
The tentative list of Printer and the corresponding Device Operations is
shown in Table 1:
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Table 1 - List of Printer Operations and corresponding Device Operations
Printer Operation Corresponding Device Operation
equivalent
Disable-Printer Disable-Device
Enable-Printer Enable-Device
Pause-Printer (IPP/1.1 - [RFC2911] Pause-Device-Now
- one interpretation)
no Pause-Device-After-Current-Copy
Pause-Printer-After-Current-Job Pause-Device-After-Current-Job
Resume-Printer (IPP/1.1 - Resume-Device
[RFC2911])
Hold-New-Jobs no
Release-Held-New-Jobs no
Deactivate-Printer Deactivate-Device
Activate-Printer Activate-Device
Purge-Jobs (IPP/1.1 - [RFC2911]) Purge-Device
Restart-Printer Reset-Device
Shutdown-Printer Power-Off-Device
Startup-Printer Power-On-Device
There are no conformance dependencies between Printer Operations and
Device Operations. Either may be supported without supporting the
corresponding operations.
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4 IANA Considerations
This document does not define anything to be registered. When a
document is produced that defines operations that meet the
requirements in this document, those operations will be registered
according to the procedures in [RFC2911] section 6.4.
5 Internationalization Considerations
This document has the same localization considerations as the [RFC2911].
6 Security Considerations
This document defines the requirements for operations that are intended
to be used by an operator or system administrator. These operations,
when defined, would affect how the Printer behaves and establish policy
and/or operating behavior that ordinary users shouldn't be able to
perform. Printer implementations that support such operations should
authenticate users and authorized them as being an operator or a system
administrator for the system. Otherwise, unprivileged users could
affect the policy and behavior of IPP Printers, thereby affecting other
users. Similarly clients that supports such operations should be
prepared to provide the necessary authentication information. See the
security provisions in [RFC2911] for authentication, such as TLS.
7 Author's Addresses
Carl Kugler
IBM
Boulder CO
Phone: (303) 924-5060
FAX:
e-mail: kugler@us.ibm.com
Tom Hastings
Xerox Corporation
737 Hawaii St. ESAE 231
El Segundo, CA 90245
Phone: 310-333-6413
Fax: 310-333-5514
e-mail: hastings@cp10.es.xerox.com
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Harry Lewis
IBM
Boulder CO
Phone: (303) 924-5337
FAX:
e-mail: harryl@us.ibm.com
IPP Web Page: http://www.pwg.org/ipp/
IPP Mailing List: ipp@pwg.org
To subscribe to the ipp mailing list, send the following email:
1) send it to majordomo@pwg.org
2) leave the subject line blank
3) put the following two lines in the message body:
subscribe ipp
end
Implementers of this specification document are encouraged to join the
IPP Mailing List in order to participate in any discussions of
clarification issues and review of registration proposals for additional
attributes and values. In order to reduce spam the mailing list rejects
mail from non-subscribers, so you must subscribe to the mailing list in
order to send a question or comment to the mailing list.
8 References
[ipp-iig]
Hastings, T., Manros, C., "Internet Printing Protocol/1.1: draft-
ietf-ipp-implementers-guide-v11-03.txt, work in progress, July 17,
2001.
[ipp-ntfy]
Herriot, R., Hastings, T., Isaacson, S., Martin, J., deBry, R.,
Shepherd, M., Bergman, R., "Internet Printing Protocol/1.1: IPP
Event Notifications and Subscriptions", <draft-ietf-ipp-not-spec-
07.txt>, work in progress, July 17, 2001.
[ipp-ops-set2]
Kugler, C., , Hastings, T., Lewis, H, "Internet Printing Protocol
(IPP): Job and Printer Administrative Operations", <draft-ietf-ipp-
ops-set2-03.txt>, work in progress, July 17, 2001.
[RFC2566]
R. deBry, T. Hastings, R. Herriot, S. Isaacson, P. Powell,
"Internet Printing Protocol/1.0: Model and Semantics", RFC 2566,
April 1999.
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[RFC2910]
Herriot, R., Butler, S., Moore, P., Tuner, R., "Internet Printing
Protocol/1.1: Encoding and Transport", RFC 2910, September, 2000.
[RFC2911]
R. deBry, T. Hastings, R. Herriot, S. Isaacson, P. Powell,
"Internet Printing Protocol/1.0: Model and Semantics", RFC 2911,
September 2000.
9 Appendix A: Description of base IPP documents
The base set of IPP documents includes:
Design Goals for an Internet Printing Protocol [RFC2567]
Rationale for the Structure and Model and Protocol for the Internet
Printing Protocol [RFC2568]
Internet Printing Protocol/1.1: Model and Semantics [RFC2911]
Internet Printing Protocol/1.1: Encoding and Transport [RFC2910]
Internet Printing Protocol/1.1: Implementer's Guide [ipp-iig]
Mapping between LPD and IPP Protocols [RFC2569]
Internet Printing Protocol (IPP): IPP Event Notifications and
Subscriptions [ipp-ntfy]
The "Design Goals for an Internet Printing Protocol" 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. It calls out a subset of end user requirements that are
satisfied in IPP/1.0. A few optional operator operations have been
added to IPP/1.1.
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
specification documents, and gives background and rationale for the IETF
working group's major decisions.
The "Internet Printing Protocol/1.1: Model and Semantics" document
describes a simplified model with abstract objects, their attributes,
and their operations that are independent of encoding and transport. It
introduces a Printer and a Job object. The Job object optionally
supports multiple documents per Job. It also addresses security,
internationalization, and directory issues.
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The "Internet Printing Protocol/1.1: Encoding and Transport" document is
a formal mapping of the abstract operations and attributes defined in
the model document onto HTTP/1.1 [RFC2616]. It defines the encoding
rules for a new Internet MIME media type called "application/ipp". This
document also defines the rules for transporting over HTTP a message
body whose Content-Type is "application/ipp". This document defines the
'ippget' scheme for identifying IPP printers and jobs.
The "Internet Printing Protocol/1.1: Implementer's Guide" document gives
insight and advice to implementers of IPP clients and IPP objects. It
is intended to help them understand IPP/1.1 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.
The "IPP Event Notifications and Subscriptions" document defines an
extension to IPP/1.0 [RFC2566, RFC2565] and IPP/1.1 [RFC2911, RFC2910].
This extension allows a client to subscribe to printing related Events
and defines the semantics for delivering asynchronous Event
Notifications to the specified Notification Recipient via a specified
Delivery Method (i.e., protocols) defined in (separate) Delivery Method
documents.
10 Appendix B: Full Copyright Statement
Copyright (C) The Internet Society (1998,1999). 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.
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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.
Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
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