| Rfc | 3998 |
|---|
| Title | Internet Printing Protocol (IPP): Job and Printer Administrative
Operations |
|---|
| Author | C. Kugler, H. Lewis, T. Hastings, Ed. |
|---|
| Date | March 2005 |
|---|
| Format: | TXT, HTML |
|---|
| Status: | PROPOSED STANDARD |
|---|
|
Network Working Group C. Kugler
Request for Comments: 3998 H. Lewis
Category: Standards Track IBM Corporation
T. Hastings, Ed.
Xerox Corporation
March 2005
Internet Printing Protocol (IPP):
Job and Printer Administrative Operations
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2005).
Abstract
This document specifies the following 16 additional OPTIONAL system
administration operations for use with the Internet Printing
Protocol/1.1 (IPP), plus a few associated attributes, values, and
status codes, and using the IPP Printer object to manage printer
fan-out and fan-in.
Printer operations: Job operations:
Enable-Printer and Disable-Printer Reprocess-Job
Pause-Printer-After-Current-Job Cancel-Current-Job
Hold-New-Jobs and Release-Held-New-Jobs Suspend-Current-Job
Deactivate-Printer and Activate-Printer Resume-Job
Restart-Printer Promote-Job
Shutdown-Printer and Startup-Printer Schedule-Job-After
Table of Contents
1. Introduction.................................................. 4
2. Terminology................................................... 4
2.1. Conformance Terminology................................. 4
2.2. Other Terminology....................................... 5
3. Definition of the Printer Operations.......................... 6
3.1. The Disable and Enable Printer Operations............... 7
3.1.1. Disable-Printer Operation....................... 7
3.1.2. Enable-Printer Operation........................ 8
3.2. The Pause and Resume Printer Operations................. 8
3.2.1. Pause-Printer-After-Current-Job Operation....... 9
3.3. Hold and Release New Jobs Operations.................... 11
3.3.1. Hold-New-Jobs Operation......................... 11
3.3.2. Release-Held-New-Jobs Operation................. 12
3.4. Deactivate and Activate Printer Operations.............. 12
3.4.1. Deactivate-Printer Operation.................... 13
3.4.2. Activate-Printer Operation...................... 13
3.5. Restart-Printer, Shutdown-Printer,
and Startup-Printer Operations.......................... 14
3.5.1. Restart-Printer Operation....................... 14
3.5.2. Shutdown-Printer Operation...................... 14
3.5.3. Startup-Printer Operation....................... 15
4. Definition of the Job Operations.............................. 16
4.1. Reprocess-Job Operation................................. 17
4.2. Cancel-Current-Job Operation............................ 17
4.3. Suspend and Resume Job Operations....................... 18
4.3.1. Suspend-Current-Job Operation................... 19
4.3.2. Resume-Job Operation............................ 20
4.4. Job Scheduling Operations............................... 20
4.4.1. Promote-Job Operation........................... 20
4.4.2. Schedule-Job-After Operation.................... 21
5. Additional Status Codes....................................... 23
5.1. 'server-error-printer-is-deactivated' (0x050A).......... 23
6. Use of Operation Attributes
That Are Messages from the Operator........................... 23
7. New Printer Description Attributes............................ 26
7.1. subordinate-printers-supported (1setOf uri)............. 26
7.2. parent-printers-supported (1setOf uri).................. 26
8. Additional Values for
the "printer-state-reasons" Printer Description Attribute..... 26
8.1. 'hold-new-jobs' Value................................... 27
8.2. 'deactivated' Value..................................... 27
9. Additional Values for
the "job-state-reasons" Job Description attribute............. 27
9.1. 'job-suspended' Value................................... 27
10. Use of the Printer Object to Represent
IPP Printer Fan-Out and IPP Printer Fan-In.................... 27
10.1. IPP Printer Fan-Out..................................... 28
10.2. IPP Printer Fan-In...................................... 28
10.3. Printer Object Attributes Used
to Represent Printer Fan-Out and Printer Fan-In......... 29
10.4. Subordinate Printer URI................................. 29
10.5. Printer Object Attributes Used
to Represent Output Device Fan-Out...................... 30
10.6. Figures to Show All Possible Configurations............. 30
10.7. Forwarding Requests..................................... 33
10.7.1. Forwarding Requests
that Affect Printer Objects..................... 33
10.7.2. Forwarding Requests that Affect Jobs............ 35
10.8. Additional Attributes to Help with Fan-Out.............. 37
10.8.1. output-device-assigned (name(127))
Job Description Attribute - from [RFC2911]...... 37
10.8.2. original-requesting-user-name (name(MAX))
Operation and Job Description Attribute......... 37
10.8.3. requesting-user-name (name(MAX))
Operation Attribute - Additional Semantics...... 38
10.8.4. job-originating-user-name (name(MAX))
Job Description Attribute -
Additional Semantics............................ 38
11. Conformance Requirements...................................... 38
12. Normative References.......................................... 39
13. Informative References........................................ 40
14. IANA Considerations........................................... 40
14.1. Attribute Registrations................................. 41
14.2. Attribute Value Registrations........................... 41
14.3. Additional Enum Attribute Value Registrations........... 41
14.4. Operation Registrations................................. 42
14.5. Status Code Registrations............................... 43
15. Internationalization Considerations........................... 43
16. Security Considerations....................................... 43
17. Summary of Base IPP Documents................................. 44
Authors' Addresses................................................ 45
Full Copyright Statement.......................................... 46
List of Tables
Table 1. Printer Operation Operation-Id Assignments.............. 6
Table 2. Pause and Resume Printer Operations..................... 9
Table 3. State Transition Table for
Pause-Printer-After-Current-Job Operation............... 10
Table 4. Job Operation Operation-Id Assignments.................. 16
Table 5. Operation Attribute Support for Printer Operations...... 24
Table 6. Operation Attribute Support for Job Operations.......... 25
Table 7. Forwarding Operations that Affect Printer Objects....... 34
Table 8. Forwarding Operations that Affect Jobs Objects.......... 36
Table 9. Conformance Requirement Dependencies for Operations..... 38
Table 10. Conformance Requirement Dependencies
for "printer-state-reasons" Values...................... 39
Table 11. Conformance Requirement Dependencies
for "job-state-reasons" Values.......................... 39
List of Figures
Figure 1. Embedded Printer Object................................ 31
Figure 2. Hosted Printer Object.................................. 31
Figure 3. Output Device Fan-Out.................................. 31
Figure 4. Chained IPP Printer Objects............................ 32
Figure 5. IPP Printer Object Fan-Out............................. 32
Figure 6. IPP Printer Object Fan-In.............................. 33
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.
This document defines additional OPTIONAL end user, operator, and
administrator operations used to control Jobs and Printers. In
addition, this document extends the semantic model of the Printer
object by allowing them to be configured into trees and/or inverted
trees that represent Printer object Fan-Out and Printer object Fan-
In, respectively. The special case of a tree with only a single
Subordinate node represents Chained Printers. This document is a
registration proposal for an extension to IPP/1.0 and IPP/1.1
following the registration procedures in those documents.
The requirements and use cases for this document are defined in
[RFC3239].
2. Terminology
This section defines the terminology used throughout this document.
2.1. Conformance Terminology
Capitalized terms such as MUST, MUST NOT, REQUIRED, SHOULD, SHOULD
NOT, MAY, NEED NOT, and OPTIONAL have special meaning relating to
conformance as defined in RFC 2119 [RFC2119] and [RFC2911], section
12.1. If an implementation supports the extension defined in this
document, then these terms apply; otherwise, they do not. These
terms define conformance to this document only; they do not affect
conformance to other documents, unless explicitly stated otherwise.
2.2. Other Terminology
This document uses terms such as "client", "Printer", "Job",
"attributes", "keywords", "operation", 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: although this term is capitalized in this
specification (but not in [RFC2911]), there is no formal object
called an Output Device defined in this document (or in [RFC2911]).
Output Device Fan-Out - A configuration in which an IPP Printer
controls more than 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 zero
or more Subordinate Printers.
Leaf Printer - An IPP Printer object that has no Subordinate
Printers.
Non-Leaf Printer - An IPP Printer object that has one or more
Subordinate Printers. A Non-Leaf Printer is also called a Parent
Printer.
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. Definition of the Printer Operations
All Printer Operations are directed at Printer objects. A client
MUST always supply the "printer-uri" operation attribute in order to
identify the correct target of the operation. These descriptions
assume all of the common semantics of the IPP/1.1 Model and Semantics
document ([RFC2911], section 3.1).
The Printer Operations defined in this document are summarized in
Table 1.
Table 1. Printer Operation Operation-Id Assignments
Operation Name Operation-Id Brief Description
--------------------------------------------------------------------
Enable-Printer 0x22 Allows the target Printer to accept
Job Creation operations.
Disable-Printer 0x23 Prevents the target Printer from
accepting Job Creation operations.
Pause-Printer- 0x24 Pauses the Printer after the current
After-Current- job has been sent to the Output
Job Device.
Hold-New-Jobs 0x25 Finishes processing all currently
pending jobs. Any new jobs are
placed in the 'pending-held' state.
Release-Held- 0x26 Releases all jobs to the 'pending'
New-Jobs state that had been held by the
effect of a previous Hold-New-Jobs
operation and condition the Printer
so that it no longer holds new jobs.
Deactivate- 0x27 Puts the Printer into a read-only
Printer deactivated state.
Activate- 0x28 Restores the Printer to normal
Printer activity.
Restart-Printer 0x29 Restarts the target Printer and re-
initializes the software.
Shutdown- 0x2A Shuts down the target Printer so that
Printer it cannot be restarted or queried.
Startup-Printer 0x2B Starts up the instance of the Printer
object.
All of the operations in this document are OPTIONAL for an IPP object
to support. Unless the specification of an OPTIONAL operation
requires support of another OPTIONAL operation, conforming
implementations may support any combination of these operations.
Many of the operations come in pairs, so both are REQUIRED if either
one is implemented.
3.1. The Disable and Enable Printer Operations
This section defines the OPTIONAL Disable-Printer and Enable-Printer
operations that stop and start the IPP Printer object from accepting
new IPP jobs. If either of these operations are supported, both MUST
be supported.
These operations allow the operator to control whether the Printer
will accept new Job Creation (Print-Job, Print-URI, and Create-Job)
operations. These operations have no other effect on the Printer, so
the Printer continues to accept all other operations and continues to
schedule and process jobs normally. In other words, these operations
control the "input of new jobs" to the IPP Printer, and the Pause and
Resume operations (see section 3.2) independently control the "output
of new jobs" from the IPP Printer to the Output Device.
3.1.1. Disable-Printer Operation
This OPTIONAL operation allows a client to stop the Printer object
from accepting new jobs; i.e., it causes the Printer to reject
subsequent Job Creation operations and return the 'server-error-not-
accepting-jobs' status code. The Printer still accepts all other
operations, including Validate-Job, Send-Document, and Send-URI
operations. Thus a Disable-Printer operation allows a client to
continue submitting multiple documents of a multiple document job if
the Create-Job operation had already been accepted. All previously
created or submitted Jobs and all Jobs currently processing continue
unaffected.
The IPP Printer MUST accept the request in any state. The Printer
sets the value of its "printer-is-accepting-jobs" READ-ONLY Printer
Description attribute to 'false' (see [RFC2911], section 4.4.20), no
matter what the previous value was. This operation has no immediate
or direct effect on the Printer's "printer-state" and "printer-
state-reasons" attributes.
Access Rights: The authenticated user (see [RFC2911], section 8.3)
performing this operation must be an operator or administrator of the
Printer object (see [RFC2911] sections 1 and 8.5).
The Disable-Printer Request and Disable-Printer Response have the
same attribute groups and attributes as do the Pause-Printer
operation (see [RFC2911], sections 3.2.7.1 and 3.2.7.2), including
the new "printer-message-from-operator" operation attribute (see
section 6).
3.1.2. Enable-Printer Operation
This OPTIONAL operation allows a client to start the Printer object
accepting jobs; i.e., it causes the Printer to accept subsequent Job
Creation operations. The Printer still accepts all other operations.
All previously submitted and currently processing Jobs continue
unaffected.
The IPP Printer MUST accept the request in any state. The Printer
sets the value of its "printer-is-accepting-jobs" READ-ONLY Printer
Description attribute to 'true' (see [RFC2911], section 4.4.20), no
matter what the previous value was. This operation has no immediate
or direct effect on the Printer's "printer-state" and "printer-
state-reasons" attributes.
Access Rights: The authenticated user (see [RFC2911], section 8.3)
performing this operation must be an operator or administrator of the
Printer object (see [RFC2911] sections 1 and 8.5).
The Enable-Printer Request and Enable-Printer Response have the same
attribute groups and attributes as does the Pause-Printer operation
(see [RFC2911], sections 3.2.8.1 and 3.2.8.2), including the new
"printer-message-from-operator" operation attribute (see section 6).
3.2. The Pause and Resume Printer Operations
This section leaves the OPTIONAL IPP/1.1 Pause-Printer (see
[RFC2911], sections 3.2.7) ambiguous as to whether it stops the
Printer immediately or after the current job. It also defines the
OPTIONAL Pause-Printer-After-Current-Job operation as following the
current job. These operations affect the scheduling of IPP jobs. If
either of these Pause Printer operations are supported, then the
Resume-Printer operation MUST be supported.
These operations allow the operator to control whether the Printer
will send new IPP jobs to the associated Output Device(s) that the
IPP Printer object represents. These operations have no other effect
on the Printer, so the Printer continues to accept all operations.
In other words, these operations control the "output of new jobs" to
the Output Device(s), and the Disable and Enable Printer Operations
(see section 3.1) independently control the "input of new jobs" to
the IPP Printer.
Table 2. Pause and Resume Printer Operations
Pause and Resume Printers Description
--------------------------------------------------------------------
IPP/1.1 Pause Printer Stops the IPP Printer from sending
new IPP Jobs to the Output Device(s)
either immediately or after the
current job completes, depending on
implementation, as defined in
[RFC2911].
Pause-Printer-After- Stops the IPP Printer from sending
Current-Job new IPP Jobs to the Output Device(s)
after the current jobs finish.
Resume-Printer Starts the IPP Printer sending IPP
Jobs to the Output Device again.
3.2.1. Pause-Printer-After-Current-Job Operation
This OPTIONAL operation allows a client to stop the Printer object
from sending IPP jobs to any of its Output Devices or Subordinate
Printers. If the IPP Printer is in the middle of sending an IPP job
to an Output Device or Subordinate Printer, the IPP Printer MUST
complete sending that Job. However, after receiving this operation,
the IPP Printer MUST NOT send any additional IPP jobs to any of its
Output Devices or Subordinate Printers. In addition, after having
received this operation, the IPP Printer MUST NOT start processing
any more jobs, so additional jobs MUST NOT enter the 'processing'
state.
If the IPP Printer is not sending an IPP Job to the Output Device or
Subordinate Printer (whether or not the Output Device or Subordinate
Printer is busy processing any jobs), the IPP Printer object
transitions immediately to the 'stopped' state by setting its
"printer-state" attribute to 'stopped', removing the 'moving-to-
paused' value, if present, from its "printer-state-reasons"
attribute, and adding the 'paused' value to its "printer-state-
reasons" attribute.
If the implementation will take appreciable time to complete sending
an IPP job that it has started sending to an Output Device or
Subordinate Printer, the IPP Printer adds the 'moving-to-paused'
value to the Printer object's "printer-state-reasons" attribute (see
section [RFC2911], 4.4.12). When the IPP Printer has completed
sending IPP jobs that it was in the process of sending, the Printer
object transitions to the 'stopped' state by setting its "printer-
state" attribute to 'stopped', removing the 'moving-to-paused' value,
if present, from its "printer-state-reasons" attribute, and adding
the 'paused' value to its "printer-state-reasons" attribute.
This operation MUST NOT affect the acceptance of Job Creation
requests (see Disable-Printer Operation, section 3.1.1).
For any jobs that are 'pending' or 'pending-held', the 'printer-
stopped' values of the jobs' "job-state-reasons" attribute also
apply. However, the IPP Printer NEED NOT update those jobs' "job-
state-reasons" attributes and only have to return the 'printer-
stopped' value when those jobs are queried by using the Get-Job-
Attributes or Get-Jobs operations (so-called "lazy evaluation").
The IPP Printer MUST accept the request in any state and transition
the Printer to the indicated new "printer-state", and it MUST add the
indicated value to "printer-state-reasons" attribute before returning
as follows:
Table 3. State Transition Table for Pause-Printer-After-Current-Job
Operation
Current New "printer IPP Printer's response status
"printer- "printer- -state- code and action (REQUIRED/
state" state" reasons" OPTIONAL state transition for
a Printer to support):
--------------------------------------------------------------------
'idle' 'stopped' 'paused' REQUIRED: 'successful-ok'
'processing' 'processing' 'moving- OPTIONAL: 'successful-ok';
to- Later, when the IPP Printer
paused' has finished sending IPP jobs
to an Output Device, the
"printer-state" becomes
'stopped', and the 'paused'
value replaces the 'moving-to-
paused' value in the "printer-
state-reasons" attribute
'processing' 'stopped' 'paused' REQUIRED: 'successful-ok';
the IPP Printer wasn't in the
middle of sending an IPP job
to an Output Device
'stopped' 'stopped' 'paused' REQUIRED: 'successful-ok'
Access Rights: The authenticated user (see [RFC2911], section 8.3)
performing this operation must be an operator or administrator of the
Printer object (see [RFC2911], sections 1 and 8.5).
The Pause-Printer-After-Current-Job Request and Pause-Printer-After-
Current-Job Response have the same attribute groups and attributes as
does the Pause-Printer operation (see [RFC2911], sections 3.2.7.1 and
3.2.7.2), including the new "printer-message-from-operator" operation
attribute (see section 6).
3.3. Hold and Release New Jobs Operations
This section defines operations to condition the Printer to hold any
new jobs and to release them.
3.3.1. Hold-New-Jobs Operation
This OPTIONAL operation allows a client to condition the Printer to
complete the current 'pending' and 'processing' IPP Jobs but not to
start processing any subsequently created IPP Jobs. If the IPP
Printer is in the middle of sending an IPP job to an Output Device or
Subordinate Printer, the IPP Printer MUST complete sending that Job.
Furthermore, the IPP Printer MUST send all of the current 'pending'
IPP Jobs to the Output Device(s) or Subordinate IPP Printer
object(s). Any subsequently received Job Creation operations will
cause the IPP Printer to put the Job into the 'pending-held' state,
with the 'job-held-on-create' value being added to the job's "job-
state-reasons" attribute. Thus all newly accepted jobs will be
automatically held by the Printer.
When the Printer completes all the 'pending' and 'processing' jobs,
it enters the 'idle' state as usual. An operator monitoring Printer
state changes will know when the Printer has completed all current
jobs because the Printer enters the 'idle' state.
This operation MUST NOT affect the acceptance of Job Creation
requests (see Disable-Printer Operation, section 3.1.1), except to
put the Jobs into the 'pending-held' state, instead of the 'pending'
or 'processing' state.
The IPP Printer MUST accept the request in any state, MUST NOT
transition the Printer to any other "printer-state", and MUST add the
'hold-new-jobs' value to the Printer's "printer-state-reasons"
attribute (whether the value was present or not).
Access Rights: The authenticated user (see [RFC2911], section 8.3)
performing this operation must be an operator or administrator of the
Printer object (see [RFC2911], sections 1 and 8.5).
The Hold-New-Jobs Request and Hold-New-Jobs Response have the same
attribute groups and attributes as does the Pause-Printer operation
(see [RFC2911], sections 3.2.7.1 and 3.2.7.2), including the new
"printer-message-from-operator" operation attribute (see section 6).
3.3.2. Release-Held-New-Jobs Operation
This OPTIONAL operation allows a client to undo the effect of a
previous Hold-New-Jobs operation. In particular, the Printer
releases all the jobs that it held as a consequence of a Hold-New-
Jobs operations; i.e., while the 'hold-new-jobs' value was present in
the Printer's "printer-state-reasons" attribute. In addition, the
Printer MUST accept this request in any state, MUST NOT transition
the Printer to any other "printer-state", and MUST remove the 'hold-
new-jobs' value from its "printer-state-reasons" attribute (whether
the value was present or not) so that the Printer no longer holds
newly created jobs.
Access Rights: The authenticated user (see [RFC2911], section 8.3)
performing this operation must be an operator or administrator of the
Printer object (see [RFC2911], sections 1 and 8.5).
The Release-Held-New-Jobs Request and Release-Held-New-Jobs Response
have the same attribute groups and attributes as the Pause-Printer
operation (see [RFC2911], sections 3.2.7.1 and 3.2.7.2), including
the new "printer-message-from-operator" operation attribute (see
section 6).
3.4. Deactivate and Activate Printer Operations
This section defines the OPTIONAL Deactivate-Printer and Activate-
Printer operations that stop and start the IPP Printer object from
accepting all requests except queries and performing work. If either
of these operations are supported, both MUST be supported.
These operations allow the operator to put the Printer into a dormant
read-only condition and to take it out of this condition.
3.4.1. Deactivate-Printer Operation
This OPTIONAL operation allows a client to stop the Printer object
from sending IPP jobs to any of its Output Devices or Subordinate
Printers (Pause-Printer-After-Current-Job) and to stop the Printer
object from accepting any requests but query requests. The Printer
performs a Disable-Printer and a Pause-Printer-After-Current-Job
operation immediately. If these two operations cannot be completed
immediately, it includes use of all of the "printer-state-reasons".
In addition, the Printer MUST immediately reject all requests, except
for Activate-Printer, queries (Get-Printer-Attributes, Get-Job-
Attributes, Get-Jobs, etc.), Send-Document, and Send-URI (so that
partial job submission can be completed, see section 3.1.1). The
Printer MUST then return the 'server-error-service-unavailable'
status code.
The IPP Printer MUST accept the request in any state. Immediately,
the Printer MUST set the 'deactivated' value in its "printer-state-
reasons" attribute. Note: neither the Disable-Printer nor the
Pause-Printer-After-Current-Job set the 'deactivated' value.
Access Rights: The authenticated user (see [RFC2911], section 8.3)
performing this operation must be an operator or administrator of the
Printer object (see [RFC2911], sections 1 and 8.5).
The Deactivate-Printer Request and Deactivate-Printer Response have
the same attribute groups and attributes as does the Pause-Printer
operation (see [RFC2911], sections 3.2.7.1 and 3.2.7.2), including
the new "printer-message-from-operator" operation attribute (see
section 6).
3.4.2. Activate-Printer Operation
This OPTIONAL operation allows a client to undo the effects of the
Deactivate-Printer; i.e., it allows the Printer object to start
sending IPP jobs to any of its Output Devices or Subordinate Printers
(Pause-Printer-After-Current-Job) and starts the Printer object from
accepting any requests. The Printer performs an Enable-Printer and a
Resume-Printer operation immediately. In addition, the Printer MUST
immediately start accepting all requests.
The IPP Printer MUST accept the request in any state. The Printer
MUST immediately remove the 'deactivated' value from its "printer-
state-reasons" attribute (whether it is present or not).
Access Rights: The authenticated user (see [RFC2911], section 8.3)
performing this operation must be an operator or administrator of the
Printer object (see [RFC2911], sections 1 and 8.5).
The Activate-Printer Request and Activate-Printer Response have the
same attribute groups and attributes as the Pause-Printer operation
(see [RFC2911], sections 3.2.7.1 and 3.2.7.2), including the new
"printer-message-from-operator" operation attribute (see section 6).
3.5. Restart-Printer, Shutdown-Printer, and Startup-Printer Operations
This section defines the OPTIONAL Restart-Printer, Shutdown-Printer,
and Startup-Printer operations that initialize, shutdown, and start
up the Printer object, respectively. Each of these operations is
OPTIONAL, and any combination MAY be supported.
3.5.1. Restart-Printer Operation
This OPTIONAL operation allows a client to restart a Printer object
whose operation is in need of initialization because of incorrect or
erratic behavior; i.e., perform the effect of a software re-boot.
The implementation MUST attempt to save any information about Jobs
and the Printer object before re-initializing. However, this
operation MAY have drastic consequences on the running system, so the
client SHOULD first try the Deactivate-Printer operation to minimize
the effect on the current state of the system. The effects of
previous Disable-Printer, Pause Printer, and Deactivate-Printer
operations are lost.
The IPP Printer MUST accept the request in any state. The Printer
object MUST initialize its Printer's "printer-state" to 'idle',
remove the state reasons from its "printer-state-reasons" attribute,
and change its "printer-is-accepting-jobs" attribute to 'true'.
Access Rights: The authenticated user (see [RFC2911], section 8.3)
performing this operation must be an operator or administrator of the
Printer object (see [RFC2911], sections 1 and 8.5).
The Restart-Printer Request and Restart-Printer Response have the
same attribute groups and attributes as does the Pause-Printer
operation (see [RFC2911], sections 3.2.8.1 and 3.2.8.2), including
the new "printer-message-from-operator" operation attribute (see
section 6).
3.5.2. Shutdown-Printer Operation
This OPTIONAL operation allows a client to shutdown a Printer; i.e.,
to stop processing jobs without losing any jobs and to make the
Printer object unavailable for any operations using the IPP protocol.
There is no way to bring the instance of the Printer object back to
being used, except for the Startup-Printer (see section 3.5.3), which
starts up a new instance of the Printer object for hosted
implementations. The purpose of Shutdown-Printer is to shutdown the
Printer for an extended period, not to reset the device(s) or modify
a Printer attribute. See Restart-Printer (section 3.5.1) and
Startup-Printer (section 3.5.3) for the way to initialize the
software. See the Disable-Printer operation (section 3.1) for a way
for the client to stop the Printer from accepting Job Creation
requests without stopping processing or shutting down.
The Printer MUST add the 'shutdown' value (see [RFC2911], section
4.4.11) immediately to its "printer-state-reasons" Printer
Description attribute. It then performs a Deactivate-Printer
operation (see section 3.4.1), which in turn performs Disable-Printer
and Pause-Printer-After-Current-Job operations).
Note: To shutdown the Printer after all the currently submitted jobs
have completed, the operator issues a Disable-Printer operation (see
section 3.1.1) and then waits until all the jobs have completed. The
Printer goes into the 'idle' state before issuing the Shutdown-
Printer operation.
The Printer object MUST accept this operation in any state and
transition the Printer object through the "printer-states" and
"printer-state-reasons" defined for the Pause-Printer-After-Current-
Job operation until the activity is completed and the Printer object
disappears.
Access Rights: The authenticated user (see [RFC2911], section 8.3)
performing this operation must be an operator or administrator of the
Printer object (see [RFC2911], sections 1 and 8.5).
The Shutdown-Printer Request and Shutdown-Printer Response have the
same attribute groups and attributes as does the Pause-Printer
operation (see [RFC2911], sections 3.2.7.1 and 3.2.7.2), including
the new "printer-message-from-operator" operation attribute (see
section 6).
3.5.3. Startup-Printer operation
This OPTIONAL operation allows a client to start up an instance of a
Printer object, provided that there isn't one already initiated. The
purpose of Startup-Printer is to allow a hosted implementation of the
IPP Printer object (i.e., a Server that implements an IPP Printer on
behalf of a networked or local Output Device) to be started after the
host is available (by means outside this document). See section
3.5.1 for the way to initialize the software or reset the Output
Device(s) when the IPP Printer object has already been initiated.
The host MUST accept this operation only when the Printer object has
not been initiated. If the Printer object already exists, the host
must return the 'client-error-not-possible' status code.
The result of this operation MUST be with the Printer object's
"printer-state" set to 'idle', the state reasons removed from its
"printer-state-reasons" attribute, and its "printer-is-accepting-
jobs" attribute set to 'false'. Then the operator can reconfigure
the Printer before performing an Enable-Printer operation. However,
when a Printer is first powered up, it is RECOMMENDED that its
"printer-is-accepting-jobs" attribute be set to 'true' in order to
achieve easy "out of the box" operation.
Access Rights: The authenticated user (see [RFC2911], section 8.3)
performing this operation must be an operator or administrator of the
Printer object (see [RFC2911], sections 1 and 8.5).
The Shutdown-Printer Request and Shutdown-Printer Response have the
same attribute groups and attributes as does the Pause-Printer
operation (see [RFC2911] sections 3.2.7.1 and 3.2.7.2), including the
new "printer-message-from-operator" operation attribute (see section
6).
4. Definition of the Job Operations
All Job operations are directed at Job objects. A client MUST always
supply some means to identify the Job object in order to select the
correct target of the operation. That job identification MAY either
be a single Job URI or a combination of a Printer URI and a Job ID.
The IPP object implementation MUST support both forms of
identification for every job.
The Job Operations defined in this document are summarized in Table
4.
Table 4. Job Operation Operation-Id Assignments
Operation Name Operation-Id Brief description
--------------------------------------------------------------------
Reprocess-Job 0x2C Creates a copy of a completed target
job with a new Job ID and processes it.
Cancel-Current- 0x2D Cancels the current job on the target
Job Printer or the specified job if it is
the current job.
Suspend- 0x2E Suspends the current processing job on
Current-Job the target Printer or the specified
job if it is the current job, allowing
other jobs to be processed instead.
Resume-Job 0x2F Resumes the suspended target job.
Promote-Job 0x30 Promotes the pending target job to be
next after the current job(s) complete.
Schedule-Job- 0x31 Schedules the target job immediately
After after the specified job, all other
scheduling factors being equal.
4.1. Reprocess-Job Operation
This OPTIONAL operation is a create job operation that allows a
client to re-process a copy of a job that had been retained in the
queue after processing was completed, canceled, or aborted (see
[RFC2911], section 4.3.7.2). This operation is the same as the
Restart-Job operation (see [RFC2911], section 3.3.7), except that the
Printer creates a new job that is a copy of the target job and the
target job is unchanged. New values are assigned to the "job-uri"
and "job-id" attributes. The new job's Job Description attributes
that track job progress, such as "job-impressions-completed", "job-
media-sheets-completed", and "job-k-octets-processed", are
initialized to 0, as with any create job operation. The target job
moves to the Job History after a suitable period, independent of
whether one or more Reprocess-Job operations have been performed upon
it.
If the Set-Job-Attributes operation is supported, then the "job-
hold-until" operation attribute MUST be supported with at least the
'indefinite' value, so that a client can modify the new job before it
is scheduled for processing by using the Set-Job-Attributes
operation. After modifying the job, the client can release the job
for processing by using the Release-Job operation specifying the
newly assigned "job-uri" or "job-id" for the new job.
4.2. Cancel-Current-Job Operation
This OPTIONAL operation allows a client to cancel the current job on
the target Printer or the specified job if it is the current job on
the Printer. See [RFC2911], section 3.3.3, for the semantics of
canceling a job. Since a Job might already be marking by the time a
Cancel-Current-Job is received, some media sheet pages might print
before the job is actually terminated.
If the client does not supply a "job-id" operation attribute, the
Printer MUST accept the request and cancel the current job if there
is a current job in the 'processing' or 'processing-stopped' state;
otherwise, it MUST reject the request and return the 'client-error-
not-possible' status code. If more than one job is in the
'processing' or 'processing-stopped' state, the one that is marking
is canceled, and the others are unaffected.
Warning: On a shared printer, there is a race condition. Between
the time when a user issues this operation and the time of its
acceptance, the current job might change to a different job. If the
user or operator is authenticated to cancel the new job, the wrong
job is canceled. To prevent this race from canceling the wrong job,
the client MAY supply the "job-id" operation attribute, which is
checked against the current job's job-id. If the job identified by
the "job-id" attribute is not the current job on the Printer (i.e.,
is not in the 'processing' or 'processing-stopped' state), the
Printer MUST reject this operation and return the 'client-error-not-
possible' status code. Otherwise, the Printer cancels the specified
job.
Access Rights: The authenticated user (see [RFC2911], section 8.3)
performing this operation must either be the job owner (as determined
in the Job Creation operation) or an operator or administrator of the
Printer object (see [RFC2911], sections 1 and 8.5).
The Cancel-Current-Job Request and Cancel-Current-Job Response have
the same attribute groups and attributes as does the Resume-Printer
operation (see [RFC2911], section 3.2.8), including the new "job-
message-from-operator" operation attribute (see section 6), with the
addition of the following Group 1 Operation attribute in the request:
"job-id" (integer(1:MAX)):
The client OPTIONALLY supplies this Operation attribute to verify
that the identified job is still the current job on the target
Printer object. The IPP object MUST support this operation
attribute if it supports this operation.
4.3. Suspend and Resume Job Operations
This section defines the Suspend-Current-Job and Resume-Job
operations. These operations allow an operator or user to suspend a
job while it is processing, allowing other jobs to be processed, and
to resume the suspended job at a later point without losing any of
the output.
If either of these operations is supported, both MUST be supported.
The Hold-Job and Release-Job operations ([RFC2911], section 3.3.5)
are for holding and releasing held jobs, not suspending and resuming
suspended jobs.
4.3.1. Suspend-Current-Job Operation
This OPTIONAL operation allows a client to stop the current job on
the target Printer or the specified job if it is the current job on
the Printer, to allow other jobs to be processed instead. The
Printer moves the current job or the target job to the 'processing-
stopped' state and sets the 'job-suspended' value (see section 9.1)
in the job's "job-state-reasons" attribute and processes other jobs.
If the client does not supply a "job-id" operation attribute, the
Printer MUST accept the request and suspend the current job if there
is a current job in the 'processing' or 'processing-stopped' state.
Otherwise, it MUST reject the request and return the 'client-error-
not-possible' status code. If more than one job is in the
'processing' or 'processing-stopped' state, all of them are
suspended.
Warning: On a shared printer, there is a race condition. Between
the time when a user issues this operation and the time of its
acceptance, the current job might change to a different job. If the
user or operator is authenticated to suspend the new job, the wrong
job is suspended. To prevent this race from pausing the wrong job,
the client MAY supply the "job-id" operation attribute, which is
checked against the current job's job-id. If the job identified by
the "job-id" attribute is not the current job on the Printer (i.e.,
is not in the 'processing' or 'processing-stopped' state), the
Printer MUST reject this operation and return the 'client-error-not-
possible' status code. Otherwise, the Printer suspends the specified
job and processed other jobs.
The Printer MUST reject a Suspend-Current-Job request (and return the
'client-error-not-possible') for a job that has been suspended, i.e.,
for a job in the 'processing-stopped' state, with the 'job-suspended'
value in its "job-state-reasons" attribute.
Access Rights: The authenticated user (see [RFC2911], section 8.3)
performing this operation must be either the job owner (as determined
in the Job Creation operation) or an operator or administrator of the
Printer object (see [RFC2911], sections 1 and 8.5).
The Suspend-Current-Job Request and Suspend-Current-Job Response have
the same attribute groups and attributes as does the Pause-Printer
operation (see [RFC2911], section 3.2.8 ), including the new "job-
message-from-operator" operation attribute (see section 6), with the
addition of the following Group 1 Operation attribute in the request:
"job-id" (integer(1:MAX)):
The client OPTIONALLY supplies this Operation attribute to verify
that the identified job is still the current job on the target
Printer object. The IPP object MUST support this operation
attribute if it supports this operation.
4.3.2. Resume-Job Operation
This OPTIONAL operation allows a client to resume the target job at
the point where it was suspended. The Printer moves the target job
to the 'pending' state and removes the 'job-suspended' value from the
job's "job-state-reasons" attribute.
If the target job is not in the 'processing-stopped' state, with the
'job-suspended' value in the job's "job-state-reasons" attribute, the
Printer MUST reject the request and return the 'client-error-not-
possible' status code, since the job was not suspended.
Access Rights: The authenticated user (see [RFC2911], section 8.3)
performing this operation must be either the job owner (as determined
in the Job Creation operation) or an operator or administrator of the
Printer object (see [RFC2911], sections 1 and 8.5).
The Resume-Job Request and Resume-Job Response have the same
attribute groups and attributes as the Release-Job operation (see
[RFC2911], section 3.3.6), including the new "job-message-from-
operator" operation attribute (see section 6).
4.4. Job Scheduling Operations
This section defines jobs that allow an operator to control the
scheduling of jobs.
4.4.1. Promote-Job Operation
This OPTIONAL operation allows a client to make the pending target
job be processed next after the current job completes. This
operation is especially useful in a production printing environment
where the operator is involved in job scheduling.
If the target job is in the 'pending' state, this operation does not
change the job's state but causes the job to be processed after the
current job(s) complete. If the target job is not in the 'pending'
state, the Printer MUST reject the request and return the 'client-
error-not-possible' status code.
If the Printer implements the "job-priority" Job Template attribute
(see [RFC2911], section 4.2.1), the Printer sets the job's "job-
priority" to the highest value supported (so that the job will print
before any of the other pending jobs). The Printer returns the
target job immediately after the current job(s) in a Get-Jobs
response (see [RFC2911], section 3.2.6) for the 'not-completed' jobs.
When the current job is completed, canceled, suspended (see section
4.3.1), or aborted, the target of this operation is processed next.
If a client issues this request (again) before the target of the
operation of the original request started processing, the target of
this new request is processed first.
IPP is specified not to require queues for job scheduling, as there
are other implementation techniques for scheduling multiple jobs,
such as re-evaluating a criteria function for each job on a
scheduling cycle. However, if an implementation does implement
queues for jobs, then the Promote-Job operation puts the specified
job at the front of the queue. A subsequent Promote-Job operation
prior to the processing of the first job puts that specified job at
the front of the queue, so that it is "in front" of the previously
promoted job.
Access Rights: The authenticated user (see [RFC2911], section 8.3)
performing this operation must be an operator or administrator of the
Printer object (see [RFC2911], sections 1 and 8.5).
The Promote-Job Request and Promote-Job Response have the same
attribute groups and attributes as does the Cancel-Job operation (see
[RFC2911], section 3.3.3), including the new "job-message-from-
operator" operation attribute (see section 6).
4.4.2. Schedule-Job-After Operation
This OPTIONAL operation allows a client to request that the Printer
schedule the target job so that it will be processed immediately
after the specified predecessor job, all other scheduling factors
being equal. This operation is specially useful in a production
printing environment where the operator is involved in job
scheduling.
If the target job is in the 'pending' state, this operation does not
change the job's state but causes the job to be processed after the
preceding job completes. The preceding job can be in the target
'pending', 'processing', or 'processing-stopped' state. If the
target job is not in the 'pending' state, or if the predecessor job
is not in the 'pending', 'processing', or 'processing-stopped' state,
the Printer MUST reject the request, and it returns the 'client-
error-not-possible' status code, as the job cannot have its position
changed.
If the Printer implements the "job-priority" Job Template attribute
(see [RFC2911], section 4.2.1), the Printer sets the job's "job-
priority" to that of the predecessor job (so that the job will print
after the predecessor job). The Printer returns the target job
immediately after the predecessor in a Get-Jobs response (see
[RFC2911], section 3.2.6) for the 'not-completed' jobs.
When the predecessor job completes processing or is canceled or
aborted while processing, the target of this operation is processed
next.
If the client does not supply a predecessor job, this operation has
the same semantics as Promote-Job (see section 4.4).
IPP is specified not to require queues for job scheduling, as there
are other implementation techniques for scheduling multiple jobs,
such as re-evaluating a criteria function for each job on a
scheduling cycle. However, if an implementation does implement
queues for jobs, then the Schedule-Job-After operation puts the
specified job immediately after the specified job in the queue. A
subsequent Schedule-Job-After operation specifying the same job will
cause its target job to be placed after that job, even though it is
between the first target job and the specified job. For example,
suppose the job queue consisted of jobs A, B, C, D, and E, in that
order. A Schedule-Job-After with job E as the target and B as the
specified job would result in the following queue: A, B, E, C, D. A
subsequent Schedule-Job-After with Job D as the target and B as the
specified job would result in the following queue: A, B, D, E, C.
In other words, the link between the two jobs in a Schedule-Job-After
operation is not retained; i.e., there is no attribute on either job
that points to the other job as a result of this operation.
Access Rights: The authenticated user (see [RFC2911], section 8.3)
performing this operation must be an operator or administrator of the
Printer object (see [RFC2911], sections 1 and 8.5).
The Schedule-Job-After Request have the same attribute groups and
attributes as does the Cancel-Job operation (see [RFC2911], section
3.3.3), plus the new "job-message-from-operator" operation attribute
(see section 6). In addition, the following operation attribute is
defined:
"predecessor-job-id":
The client OPTIONALLY supplies this attribute. The Printer MUST
support it, if it supports this operation. This attribute
specifies the job after which the target job is to be processed.
If the client omits this attribute, the Printer MUST process the
target job next, i.e., after the current job, if there is one.
The Schedule-Job-After Response has the same attribute groups,
attributes, and status codes as does the Cancel-Job operation (see
[RFC2911], section 3.3.3). The following status codes have
particular meaning for this operation:
'client-error-not-possible' - The target job was not in the 'pending'
state, or the predecessor job was not in the 'pending', 'processing',
or 'processing-stopped' state.
'client-error-not-found' - Either the target job or the predecessor
job was not found.
5. Additional Status Codes
This section defines new status codes used by the operations defined
in this document.
5.1. 'server-error-printer-is-deactivated' (0x050A)
The Printer has been deactivated by the Deactivate-Printer operation
and is only accepting the Activate-Printer (see section 3.5.1), Get-
Job-Attributes, Get-Jobs, Get-Printer-Attributes, and any other Get-
Xxxx operations. An operator can perform the Activate-Printer
operation to allow the Printer to accept other operations.
6. Use of Operation Attributes That Are Messages from the Operator
This section summarizes the usage of the "printer-message-from-
operator" and "job-message-from-operator" operation attributes
[RFC3380] that set the corresponding Printer and Job Description
attributes (see [RFC2911] for the definition of these). These
operation attributes are defined for most of the Printer and Job
operations that operators are likely to perform, respectively, so
that operators can indicate the reasons for their actions.
Table 5 shows the operation attributes defined for use with the
Printer Operations.
Table 5. Operation Attribute Support for Printer Operations
Operation Attribute A B
---------------------------------------------
attributes-charset REQ REQ
attributes-natural-language REQ REQ
printer-uri REQ REQ
requesting-user-name REQ REQ
printer-message-from-operator Note OPT
Legend:
A: Get-Printer-Attributes, Set-Printer-Attributes
B: All other Printer administrative operations, including, but
not limited to, Pause-Printer, Pause-Printer-After-Current-
Job, Resume-Printer, Hold-New-Jobs, Release-Held-New-Jobs,
Purge-Jobs, Enable-Print, Disable-Printer, Restart-
Printer, Shutdown-Printer, and Startup-Printer.
REQ: REQUIRED for a Printer to support.
OPT: OPTIONAL for a Printer to support; the Printer ignores the
attribute if it is not supported.
Note: According to [RFC3380], the Client MUST NOT supply the
"printer-message-from-operator" operation attribute in a
Get-Printer-Attributes or Set-Printer-Attributes operation;
the Printer MUST ignore this operation attribute in these
two operations. Instead, when it is used by an
operator, the client MUST supply the
"printer-message-from-operator" as (one of the) explicit
attributes being set on the Printer object with the
Set-Printer-Attributes operation.
Table 6 shows the operation attributes defined for use with the Job
operations.
Table 6. Operation Attribute Support for Job Operations
Operation Attribute A B C F
---------------------------------------------------------
attributes-charset REQ REQ REQ REQ
attributes-natural-language REQ REQ REQ REQ
printer-uri REQ REQ REQ REQ
job-uri REQ REQ REQ
job-id REQ REQ REQ REQ
requesting-user-name REQ REQ REQ REQ
job-message-from-operator OPT OPT OPT Note
message** OPT OPT OPT n/a
job-hold-until n/a n/a OPT* n/a
Legend:
A: Cancel-Job, Resume-Job, Restart-Job, Promote-Job, Schedule-Job-
After
B: Cancel-Current-Job, Suspend-Current-Job
C: Hold-Job, Release-Job, Reprocess-Job
F: Get-Job-Attributes, Set-Job-Attributes
REQ; REQUIRED for a Printer to support.
OPT: OPTIONAL for a Printer to support; the Printer ignores the
attribute if it is supplied, but not supported.
n/a: not applicable for use with the operation; the Printer ignores
the attribute.
Note: According to [RFC3380], the Client MUST NOT supply the "job-
message-from-operator" operation attribute in a Get-Job-
Attributes or Set-Job-Attributes operation; the Printer MUST
ignore this operation attribute in these two operations.
Instead, when used by an operator, the client MUST supply the
"job-message-from-operator" as (one of the) explicit attributes
being set on the Job object with the Set-Job-Attributes
operation.
*: The Printer MUST support the "job-hold-until" operation
attribute if it supports the "job-hold-until" Job Template
attribute. For the Reprocess-Job operation, the client can
hold the job and then modify the job before releasing it to
be processed.
**: In [RFC2911], the "message" operation attribute is defined to
contain a message to the operator, but [RFC2911] does not
define a Job Description attribute to store the message.
7. New Printer Description Attributes
The following new Printer Description attributes are needed to
support the new operations defined in this document and the concepts
of Printer Fan-Out (see section 10).
7.1. subordinate-printers-supported (1setOf uri)
This Printer attribute is REQUIRED if an implementation supports
Subordinate Printers (see section 10) and contains the URIs of the
immediate Subordinate Printer object(s) associated with this Printer
object. Each Non-Leaf Printer object MUST support this Printer
Description attribute. A Leaf Printer object either does not support
the "subordinate-printers-supported" attribute or does so with the
'no-value' out-of-band value (see [RFC2911], section 4.1), depending
on the implementation.
The precise format of the Subordinate Printer URIs is implementation
dependent (see section 10.4).
If the Printer object does not have an associated Output Device, the
Printer MAY automatically copy the value of the Subordinate Printer
object's "printer-name" attribute to the Job object's "output-
device-assigned" attribute (see [RFC2911], section 4.3.13). The
"output-device-assigned" Job attribute identifies the Output Device
to which the Printer object has assigned a job; for example, when a
single Printer object is supporting Device Fan-Out or Printer Fan-
Out.
7.2. parent-printers-supported (1setOf uri)
This Printer attribute is REQUIRED if an implementation supports
Subordinate Printers (see section 10) and contains the URI of the
Non-Leaf printer object(s) for which this Printer object is the
immediate Subordinate; i.e., this Printer's immediate "parent" or
"parents". Each Subordinate Printer object MUST support this Printer
Description attribute. A Printer that has no parents either does not
support the "parent-printers-supported" attribute or does so with the
'no-value' out-of-band value (see [RFC2911], section 4.1), depending
on the implementation.
8. Additional Values for the "printer-state-reasons" Printer
Description Attribute
This section defines additional values for the "printer-state-
reasons" Printer Description attribute.
8.1. 'hold-new-jobs' Value
'hold-new-jobs': The operator has issued the Hold-New-Jobs operation
(see section 3.3.1) or other means, but the output-device(s) are
taking an appreciable time to stop. Later, when all output has
stopped, the "printer-state" becomes 'stopped', and the 'paused'
value replaces the 'moving-to-paused' value in the "printer-
state-reasons" attribute. This value MUST be supported if the
Hold-New-Jobs operation is supported and the implementation takes
significant time to pause a device in certain circumstances.
8.2. 'deactivated' Value
'deactivated': A client has issued a Deactivate-Printer operation
for the Printer object (see section 3.4.1), and the Printer is in
the process of becoming deactivated or has become deactivated.
The Printer MUST reject all requests except for Activate-Printer,
queries (Get-Printer-Attributes, Get-Job-Attributes, Get-Jobs,
etc.), Send-Document, and Send-URI (so that partial job submission
can be completed; see section 3.1.1), and then return the
'server-error-service-unavailable' status code.
9. Additional Values for the "job-state-reasons" Job Description
Attribute
This section defines additional values for the "job-state-reasons"
Job Description attribute.
9.1. 'job-suspended' Value
'job-suspended': While job processing has been suspended by the
Suspend-Current-Job operation, other jobs can be processed on the
Printer. The Job can be resumed with the Resume-Job operation,
which removes this value.
10. Use of the Printer Object to Represent IPP Printer Fan-Out and IPP
Printer Fan-In
This section defines how the Printer object MAY be used to represent
IPP Printer Fan-Out and IPP Printer Fan-In. In Fan-Out, an IPP
Printer is used to represent other IPP Printer objects. In Fan-In,
several IPP Printer objects are used to represent another IPP Printer
object.
10.1. IPP Printer Fan-Out
The IPP/1.1 Model and Semantics introduces the semantic concept of an
IPP Printer object that represents more than one Output Device (see
[RFC2911], section 2.1). This concept is called "Output Device Fan-
Out". However, with Fan-Out there was no way to represent the
individual states of the Output Devices or to perform operations on a
specific Output Device. This document generalizes the semantics of
the Printer object to represent Subordinate Fan-Out Output Devices
such as IPP Printer objects. This concept is called "Printer object
Fan-Out". A Printer object that has a Subordinate Printer object is
called a Non-Leaf Printer object. Thus, a Non-Leaf Printer object
supports one or more Subordinate Printer objects in order to
represent Printer object Fan-Out. A Printer object that does not
have any Subordinate Printer objects is called a Leaf Printer object.
Each Non-Leaf Printer object submits jobs to its immediate
Subordinate Printers and otherwise controls the Subordinate Printers
by using IPP or other protocols. Whether pending jobs are kept in
the Non-Leaf Printer until a Subordinate Printer can accept them or
are kept in the Subordinate Printers depends on implementation and/or
configuration policy. Furthermore, a Subordinate Printer object MAY,
in turn, have Subordinate Printer objects. Thus a Printer object can
be both a Non-Leaf Printer and a Subordinate Printer.
A Subordinate Printer object MUST be a conforming Printer object, so
it MUST support all of the REQUIRED [RFC2911] operations and
attributes. However, with access control, the Subordinate Printer
MAY be configured so that end-user clients are not permitted to
perform any operations (or just Get-Printer-Attributes) while one or
more Non-Leaf Printer object(s) are permitted to perform any
operation.
10.2. IPP Printer Fan-In
The IPP/1.1 Model and Semantics did not preclude the semantic concept
of multiple IPP Printer objects that represent a single Output Device
(see [RFC2911], section 2.1). However, there was no way for the
client to determine whether there was a Fan-In configuration; nor was
there a way to perform operations on the Subordinate device. This
specification generalizes the semantics of the Printer object to
allow several Non-Leaf IPP Printer objects to represent a single
Subordinate Printer object. Thus a Non-Leaf Printer object MAY share
a Subordinate Printer object with one or more other Non-Leaf Printer
objects in order to represent IPP Printer Fan-In.
As with Fan-Out (see section 10.1), when a Printer object is a Non-
Leaf Printer, it MUST NOT have an associated Output Device. As with
Fan-Out, a Leaf Printer object has one or more associated Output
Devices. As with Fan-Out, the Non-Leaf Printer objects submit jobs
to their Subordinate Printer objects and otherwise control the
Subordinate Printer. As with Fan-Out, whether pending jobs are kept
in the Non-Leaf Printers until the Subordinate Printer can accept
them or are kept in the Subordinate Printer depends on the
implementation and/or configuration policy.
10.3. Printer Object Attributes Used to Represent Printer Fan-Out and
Printer Fan-In
The following Printer Description attributes are defined to represent
the relationship between Printer object(s) and their Subordinate
Printer object(s):
1. "subordinate-printers-supported" (1setOf uri) - Contains the
URI of the immediate Subordinate Printer object(s).
2. "parent-printers-supported (1setOf uri) - Contains the URI of
the Non-Leaf printer object(s) for which this Printer object is
the immediate Subordinate; i.e., this Printer's immediate
"parent" or "parents".
10.4. Subordinate Printer URI
Each Subordinate Printer object has a URI used as the target of each
operation on the Subordinate Printer. The means to configure URIs
for Subordinate Printer objects is implementation-dependent, as are
all URIs. However, there are two distinct approaches:
a. When the implementation seeks to make sure that no operation on
a Subordinate Printer object "sneaks by" the parent Printer
object (or that no Subordinate Printer is fronting for a device
that is not networked), the host part of the URI specifies the
host of the parent Printer. Then the parent Printer object can
easily reflect the state of the Subordinate Printer objects in
the parent's Printer object state and state reasons as the
operation passes "through" the parent Printer object.
b. When the Subordinate Printer is networked and the
implementation allows operations to go directly to the
Subordinate Printer (with proper access control) without
knowledge of the parent Printer object, the host part of the
URI is different from the host part of the parent Printer
object. In this a case, the parent Printer object MAY keep its
"printer-state" and "printer-state-reasons" up to date, either
by polling the Subordinate Printer object or by subscribing to
events with the Subordinate Printer object (see [RFC3995] for
means to subscribe to event notification when the Subordinate
Printer object supports IPP notification). Alternatively, the
parent Printer MAY wait until its "printer-state" and
"printer-state-reasons" attributes are queried and then query
all its Subordinate Printers in order to return the correct
values.
10.5. Printer Object Attributes Used to Represent Output Device Fan-Out
Only Leaf IPP Printer objects are allowed to have one or more
associated Output Devices. Each Leaf Printer object MAY support the
"output-devices-supported" (1setOf name(127)) to indicate the user-
friendly name(s) of the Output Device(s) that the Leaf Printer object
represents. It is RECOMMENDED that each Leaf Printer object have
only one associated Output Device, so that the individual Output
Devices can be represented completely and controlled completely by
clients. In other words, the Leaf Printer's "output-devices-
supported" attribute SHOULD have only one value.
Non-Leaf Printer MUST NOT have associated Output Devices. However, a
Non-Leaf Printer SHOULD support an "output-devices-supported" (1setOf
name(127)) Printer Description attribute that contains all the values
of its immediate Subordinate Printers. As these Subordinate Printers
MAY be Leaf or Non-Leaf, the same rules apply to them. Thus any
Non-Leaf Printer SHOULD have an "output-devices-supported" (1setOf
name(127)) attribute that contains all the values of the Output
Devices associated with Leaf Printers of its complete sub-tree.
When a configuration of Printers and Output Devices is added, moved,
or changed, there can be moments when the tree structure is not
consistent; i.e., times when a Non-Leaf Printer's "subordinate-
printers-supported" does not agree with the Subordinate Printer's
"parent-printers-supported". Therefore, the operator SHOULD first
Deactivate all Printers being configured in this way, update all
pointer attributes, and then reactivate them. A useful client tool
would validate a tree structure before Activating the Printers
involved.
10.6. Figures to Show All Possible Configurations
Figures 1, 2, and 3 are taken from [RFC2911] to show the
configurations possible with IPP/1.0 and IPP/1.1 where all Printer
objects are Leaf Printer objects. The remaining figures show
additional configurations using Non-Leaf and Leaf Printer objects.
Legend:
----> indicates a network protocol with the direction of its requests
##### indicates a Printer object that is either
embedded in an Output Device, or
hosted in a server.
The Printer object might or might not be capable
of queuing/spooling.
any indicates any network protocol or direct
connect, including IPP.
Output Device
+---------------+
| ########### |
O +--------+ | # (Leaf) # |
/|\ | client |------------IPP-----------------># Printer # |
/ \ +--------+ | # Object # |
| ########### |
+---------------+
Figure 1. Embedded Printer Object
########### Output Device
O +--------+ # (Leaf) # +---------------+
/|\ | client |---IPP----># Printer #---any->| |
/ \ +--------+ # object # | |
########### +---------------+
Figure 2. Hosted Printer Object
+---------------+
| |
+->| Output Device |
########### any/ | |
O +--------+ # (Leaf) # / +---------------+
/|\ | client |---IPP----># Printer #--*
/ \ +--------+ # Object # \ +---------------+
########### any\ | |
+->| Output Device |
| |
+---------------+
Figure 3. Output Device Fan-Out
########### ###########
O +--------+ # Non-Leaf# # subord. #
/|\ | client |---IPP----># Printer #---IPP----># Printer #
/ \ +--------+ # object # # object #
########### ###########
The Subordinate Printer can be a Non-Leaf Printer, as in Figures 4
through 6, or can be a Leaf Printer, as in Figures 1 through 3.
Figure 4. Chained IPP Printer Objects
+------IPP--------------------->###########
/ +---># subord. #
/ / # Printer #
/ ########### IPP # object #
O +--------+ # Non-Leaf# / ###########
/|\ | client |---IPP----># Printer #--*
/ \ +--------+ # object # \
\ ########### IPP ###########
\ \ # subord. #
\ +---># Printer #
+------IPP---------------------># object #
###########
The Subordinate Printer can be a Non-Leaf Printer, as in Figures 4
through 6, or can be a Leaf Printer, as in Figures 1 through 3.
Figure 5. IPP Printer Object Fan-Out
###########
# Non-Leaf#
+---># Printer #-+
/ # object # \
IPP ########### \ ###########
O +--------+ / +-IPP-># subord. #
/|\ | client |--+-----------IPP---------------># Printer #
/ \ +--------+ \ +-IPP-># object #
IPP ########### / ###########
\ # Non-Leaf# /
+---># Printer #-+
# object #
###########
The Subordinate Printer can be a Non-Leaf Printer, as in Figures 4
through 6, or can be a Leaf Printer, as in Figures 1 through 3.
Figure 6. IPP Printer Object Fan-In
10.7. Forwarding Requests
This section describes the forwarding of Job and Printer requests to
Subordinate Printer objects.
10.7.1. Forwarding Requests that Affect Printer Objects
In Printer Fan-Out, Printer Fan-In, and Chained Printers, the Non-
Leaf IPP Printer object MUST NOT forward the operations that affect
Printer objects to its Subordinate Printer objects. If a client
seeks to explicitly target a Subordinate Printer, the client MUST
specify the URI of the Subordinate Printer. The client can determine
the URI of any Subordinate Printers by querying the Printer's
"subordinate-printers-supported (1setOf uri) attribute (see section
7.1).
Table 7 lists the operations that affect Printer objects and the
forwarding behavior that a Non-Leaf Printer MUST exhibit to its
immediate Subordinate Printers. Operations that affect jobs have a
different forwarding rule (see section 10.7.2 and Table 8):
Table 7. Forwarding Operations that Affect Printer Objects
Printer Operation Non-Leaf Printer Action
---------------------------------------------------------------
Printer Operations:
Enable-Printer MUST NOT forward to any of its Subordinate
Printers
Disable-Printer MUST NOT forward to any of its Subordinate
Printers
Hold-New-Jobs MUST NOT forward to any of its Subordinate
Printers
Release-Held-New- MUST NOT forward to any of its Subordinate
Jobs Printers
Deactivate-Printer MUST NOT forward to any of its Subordinate
Printers
Activate-Printer MUST NOT forward to any of its Subordinate
Printers
Restart-Printer MUST NOT forward to any of its Subordinate
Printers
Shutdown-Printer MUST NOT forward to any of its Subordinate
Printers
Startup-Printer MUST NOT forward to any of its Subordinate
Printers
IPP/1.1 Printer See [RFC2911]
Operations:
Get-Printer- MUST NOT forward to any of its Subordinate
Attributes Printers
Pause-Printer MUST NOT forward to any of its Subordinate
Printers
Resume-Printer MUST NOT forward to any of its Subordinate
Printers
Set Operations: See [RFC3380]
Set-Printer- MUST NOT forward to any of its Subordinate
Attributes Printers
10.7.2. Forwarding Requests that Affect Jobs
Unlike Printer Operations that only affect Printer objects (see
section 10.7.1), a Non-Leaf Printer object MUST forward operations
that directly affect jobs to the appropriate Job object(s) in one or
more of its immediate Subordinate Printer objects. Forwarding is
REQUIRED since the purpose of this Job operation is to affect the
indicated job, which may have been forwarded itself. This forwarding
MAY be immediate or queued, depending on the operation and the
implementation. For example, a Non-Leaf Printer object MAY
queue/spool jobs, feeding a job at a time to its Subordinate
Printer(s), or MAY forward jobs immediately to one of its Subordinate
Printers. In either case, the Non-Leaf Printer object forwards Job
Creation operations to one of its Subordinate Printers. Only the
time of forwarding of the Job Creation operations depends on whether
the policy is to queue/spool jobs in the Non-Leaf Printer or the
Subordinate Printer.
When a Non-Leaf Printer object creates a Job object in its
Subordinate Printer, whether that Non-Leaf Printer object keeps a
fully formed Job object or just keeps a mapping from the "job-ids"
that it assigned to those assigned by its Subordinate Printer object
is IMPLEMENTATION-DEPENDENT. In either case, the Non-Leaf Printer
MUST be able to accept and carry out future Job operations that
specify the "job-id" that the Non-Leaf Printer assigned and returned
to the job submitting client.
Table 8 lists the operations that directly affect jobs and the
forwarding behavior that a Non-Leaf Printer MUST exhibit to its
Subordinate Printers.
Table 8. Forwarding Operations that Affect Jobs Objects
Operation Non-Leaf Printer action
---------------------------------------------------------------
Job operations:
Reprocess-Job MUST forward to the appropriate Job in one of
its Subordinate Printers
Cancel-Current- MUST NOT forward
Job
Resume-Job MUST forward to the appropriate Job in one of
its Subordinate Printers
Promote-Job MUST forward to the appropriate Job in one of
its Subordinate Printers
IPP/1.1 Printer
operations:
Print-Job MUST forward immediately or queue to the
appropriate Subordinate Printer
Print-URI MUST forward immediately or queue to the
appropriate Subordinate Printer
Validate-Job MUST forward to the appropriate Subordinate
Printer
Create-Job MUST forward immediately or queue to the
appropriate Subordinate Printer
Get-Jobs MUST forward to all its Subordinate Printers
Purge-Jobs MUST forward to all its Subordinate Printers
IPP/1.1 Job
operations:
Send-Document MUST forward immediately or queue to the
appropriate Job in one of its Subordinate
Printers
Send-URI MUST forward immediately or queue to the
appropriate Job in one of its Subordinate
Printers
Cancel-Job MUST forward to the appropriate Job in one of
its Subordinate Printers
Get-Job- MUST forward to the appropriate Job in one of
Attributes its Subordinate Printers if the Non-Leaf
Printer doesn't know the complete status of the
Job object
Hold-Job MUST forward to the appropriate Job in one of
its Subordinate Printers
Release-Job MUST forward to the appropriate Job in one of
its Subordinate Printers
Restart-Job MUST forward to the appropriate Job in one of
its Subordinate Printers
IPP Set operations: See [RFC3380]
Set-Job- MUST forward to the appropriate Job in one of
Attributes its Subordinate Printers
When a Printer receives a request that REQUIRES forwarding, it does
so on a "best efforts basis" and returns a response to its client
without waiting for responses from any of its Subordinate Printers.
Such forwarded requests could fail.
10.8. Additional Attributes to Help with Fan-Out
The following operation and Job Description attributes are defined to
help represent Job relationships for Fan-Out and forwarding of jobs.
10.8.1. output-device-assigned (name(127)) Job Description Attribute -
from [RFC2911]
[RFC2911] defines "output-device-assigned" as follows: "This
attribute identifies the Output Device to which the Printer object
has assigned this job. If an Output Device implements an embedded
Printer object, the Printer object NEED NOT set this attribute. If a
print server implements a Printer object, the value MAY be empty
(zero-length string) or not returned until the Printer object assigns
an Output Device to the job. This attribute is particularly useful
when a single Printer object supports multiple devices (so called
"Device Fan-Out" see [RFC2911] section 2.1)." See also section 10.1
in this specification.
10.8.2. original-requesting-user-name (name(MAX)) Operation and Job
Description Attribute
The operation attribute containing the user name of the original
user; i.e., corresponding to the "requesting-user-name" operation
attribute (see [RFC2911], section 3.2.1.1) that the original client
supplied to the first Printer object. The Printer copies the
"original-requesting-user-name" operation attribute to the
corresponding Job Description attribute.
10.8.3. requesting-user-name (name(MAX)) Operation Attribute -
Additional Semantics
The IPP/1.1 "requesting-user-name" operation attribute (see [RFC2911]
section 3.2.1.1) is updated by each client to be itself on each hop;
i.e., the "requesting-user-name" represents the client forwarding the
request, not the original client.
10.8.4. job-originating-user-name (name(MAX)) Job Description Attribute
- Additional Semantics
The "job-originating-user-name" Job Description attribute (see
[RFC2911], section 4.3.6) remains as the authenticated original user,
not the parent Printer's authenticated host, and is forwarded by each
client without changing the value.
11. Conformance Requirements
The Job and Printer Administrative operations defined in this
document are OPTIONAL operations. However, some operations MUST be
implemented if others are implemented, as shown in Table 9.
Table 9. Conformance Requirement Dependencies for Operations
Operations REQUIRED If any of these operations are
supported:
--------------------------------------------------------------------
Enable-Printer Disable-Printer
Disable-Printer Enable-Printer
Pause-Printer Resume-Printer
Resume-Printer Pause-Printer,
Pause-Printer-After-Current-Job
Hold-New-Jobs Release-Held-New-Jobs
Release-Held-New-Jobs Hold-New-Jobs
Activate-Printer, Deactivate-Printer
Disable-Printer,
Pause-Printer-After-Current-Job
Deactivate-Printer, Activate-Printer
Enable-Printer,
Resume-Printer
Restart-Printer none
Shutdown-Printer none
Startup-Printer none
Reprocess-Job none
Cancel-Current-Job none
Resume-Job Suspend-Current-Job
Suspend-Current-Job Resume-Job
Promote-Job none
Schedule-Job-After Promote-Job
Tables 10 and 11 list the "printer-state-reasons" and "job-state-
reasons" values that are REQUIRED if the indicated operations are
supported.
Table 10. Conformance Requirement Dependencies for
"printer-state-reasons" Values
"printer-state- Conformance If any of the following Printer
reasons" values: Requirement Operations are supported:
--------------------------------------------------------------------
'paused' REQUIRED Pause-Printer,
Pause-Printer-After-Current-Job,
or Deactivate-Printer
'hold-new-jobs' REQUIRED Hold-New-Jobs
'moving-to-paused' OPTIONAL Pause-Printer,
Pause-Printer-After-Current-Job,
Deactivate-Printer
'deactivated' REQUIRED Deactivate-Printer
Table 11. Conformance Requirement Dependencies for "job-state-
reasons" Values
"job-state-reasons" Conformance If any of the following Job
values: Requirement operations are supported:
'job-suspended' REQUIRED Suspend-Current-Job
'printer-stopped' REQUIRED Always REQUIRED
12. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
RFC 2246, January 1999.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC2910] Herriot, R., Butler, S., Moore, P., Turner, R., and J.
Wenn, "Internet Printing Protocol/1.1: Encoding and
Transport", RFC 2910, September 2000.
[RFC2911] Hastings, T., Herriot, R., deBry, R., Isaacson, S., and P.
Powell, "Internet Printing Protocol/1.1: Model and
Semantics", RFC 2911, September 2000.
[RFC3380] Hastings, T., Herriot, R., Kugler, C., and H. Lewis,
"Internet Printing Protocol (IPP): Job and Printer Set
Operations", RFC 3380, September 2002.
13. Informative References
[RFC2567] Wright, F., "Design Goals for an Internet Printing
Protocol", RFC 2567, April 1999.
[RFC2568] Zilles, S., "Rationale for the Structure of the Model and
Protocol for the Internet Printing Protocol", RFC 2568,
April 1999.
[RFC2569] Herriot, R., Hastings, T., Jacobs, N., and J. Martin,
"Mapping between LPD and IPP Protocols", RFC 2569, April
1999.
[RFC3196] Hastings, T., Manros, C., Zehler, P., Kugler, C., and H.
Holst, "Internet Printing Protocol/1.1: Implementor's
Guide", RFC 3196, November 2001.
[RFC3239] Kugler, C., Lewis, H., and T. Hastings, "Internet Printing
Protocol (IPP): Requirements for Job, Printer, and Device
Administrative Operations", RFC 3239, February 2002.
[RFC3995] Herriot, R. and T. Hastings, "Internet Printing Protocol
(IPP): Event Notifications and Subscriptions", RFC 3995,
February 2005.
14. IANA Considerations
This section contains the registration information that IANA added to
the IPP Registry according to the procedures defined in [RFC2911],
section 6, to cover the definitions in this document. The resulting
registrations have been published as additions to the
http://www.iana.org/assignments/ipp-registrations file.
14.1. Attribute Registrations
The following table lists all the attributes defined in this
document. These have been registered according to the procedures in
[RFC2911], section 6.2.
Name Reference Section
-------------------------------------- --------- -------
Job Description attributes:
original-requesting-user-name (name(MAX)) [RFC3998] 10.8.2
Printer Description attributes:
subordinate-printers-supported (1setOf uri) [RFC3998] 7.1
parent-printers-supported (1setOf uri) [RFC3998] 7.2
Operation attributes:
original-requesting-user-name (name(MAX)) [RFC3998] 10.8.2
14.2. Attribute Value Registrations
This section lists the additional values defined in this document for
existing attributes.
Attribute
Value Reference Section
--------------------- --------- -------
job-state-reasons (1setOf type2 keyword)
job-suspended [RFC3998] 9.1
printer-state-reasons (1setOf type2 keyword)
hold-new-jobs [RFC3998] 8.1
deactivated [RFC3998] 8.2
14.3. Additional Enum Attribute Value Registrations
The following table lists all the new enum attribute values defined
in this document. These have been registered according to the
procedures in [RFC2911], section 6.1.
Attribute (attribute syntax)
Value Name Reference Section
------- -------------------- --------- -------
operations-supported (1setOf type2 enum) [RFC2911] 4.4.1
0x0022 Enable-Printer [RFC3998] 3
0x0023 Disable-Printer [RFC3998] 3
0x0024 Pause-Printer-After-Current-Job [RFC3998] 3
0x0025 Hold-New-Jobs [RFC3998] 3
0x0026 Release-Held-New-Jobs [RFC3998] 3
0x0027 Deactivate-Printer [RFC3998] 3
0x0028 Activate-Printer [RFC3998] 3
0x0029 Restart-Printer [RFC3998] 3
0x002A Shutdown-Printer [RFC3998] 3
0x002B Startup-Printer [RFC3998] 3
0x002C Reprocess-Job [RFC3998] 4
0x002D Cancel-Current-Job [RFC3998] 4
0x002E Suspend-Current-Job [RFC3998] 4
0x002F Resume-Job [RFC3998] 4
0x0030 Promote-Job [RFC3998] 4
0x0031 Schedule-Job-After [RFC3998] 4
14.4. Operation Registrations
The following table lists all the operations defined in this
document. These have been registered according to the procedures in
[RFC2911], section 6.4.
Name Reference Section
----------------------------- --------- -------
Activate-Printer [RFC3998] 3.4.2
Cancel-Current-Job [RFC3998] 4.2
Deactivate-Printer [RFC3998] 3.4.1
Disable-Printer [RFC3998] 3.1.1
Enable-Printer [RFC3998] 3.1.2
Hold-New-Jobs [RFC3998] 3.3.1
Pause-Printer-After-Current-Job [RFC3998] 3.2.1
Promote-Job [RFC3998] 4.4.1
Release-Held-New-Jobs [RFC3998] 3.3.2
Reprocess-Job [RFC3998] 4.1
Restart-Printer [RFC3998] 3.5.1
Resume-Job [RFC3998] 4.3.2
Schedule-Job-After [RFC3998] 4.4.2
Shutdown-Printer [RFC3998] 3.5.2
Startup-Printer [RFC3998] 3.5.3
Suspend-Current-Job [RFC3998] 4.3.1
14.5. Status Code Registrations
The following table lists the status code defined in this document.
This has been registered according to the procedures in [RFC2911],
section 6.6.
Value Name Reference Section
------ ------------------------ --------- -------
0x0000:0x00FF - "successful"
none at this time
0x0100:0x01FF - "informational"
none at this time
0x0300:0x03FF - "redirection" See RFC 2911 Errata
none at this time
0x0400:0x04FF - "client-error"
none at this time
0x0500:0x05FF - "server-error"
0x050A server-error-printer-is-deactivated [RFC3998] 5.1
15. Internationalization Considerations
This document has the same localization considerations as [RFC2911].
16. Security Considerations
The IPP Model and Semantics document [RFC2911] discusses high level
security requirements (Client Authentication, Server Authentication,
and Operation Privacy). Client Authentication is the mechanism by
which the client proves its identity to the server in a secure
manner. Server Authentication is the mechanism by which the server
proves its identity to the client in a secure manner. Operation
Privacy is defined as a mechanism for protecting operations from
eavesdropping.
Printer operations defined in this specification (see section 3), as
well as Pause-Printer, Resume-Printer, and Purge-Job (defined in
[RFC2911]) are intended for use by an operator and/or administrator.
Job operations defined in this specification (see section 4) and
Cancel-Job, Hold-Job, and Release-Job (defined in [RFC2911]) are
intended for use by the job owner, operator, or administrator of the
Printer object. These operator and administrator operations affect
service for all users.
Inappropriate use of an administrative operation by an
unauthenticated end user can affect the quality of service for all
users. Therefore, IPP Printer implementations MUST support both
successful certificate-based TLS [RFC2246] client authentication and
successful operator/administrator authorization (see [RFC2911],
sections 5.2.7 and 8, and [RFC2910]) to perform the administrative
operations defined in this document. [RFC2910] requires the IPP
Printer to support the minimum cipher suite specified for TLS/1.0.
The means for authorizing an operator or administrator of the Printer
object are outside the scope of this specification, RFC 2910, and RFC
2911.
The use of TLS and Client Authentication solves the Denial of
Service, Man in the Middle, and Masquerading security threats.
17. Summary of Base IPP Documents
The base set of IPP documents includes the following:
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 [RFC3196]
Mapping between LPD and IPP Protocols [RFC2569]
"Design Goals for an Internet Printing Protocol" takes a broad look
at distributed printing functionality, and it enumerates real-life
scenarios that help clarify the features that have 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.
"Rationale for the Structure and Model and Protocol for the Internet
Printing Protocol" 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.
"Internet Printing Protocol/1.1: Model and Semantics" 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.
"Internet Printing Protocol/1.1: Encoding and Transport" 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.
"Internet Printing Protocol/1.1: Implementer's Guide" 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.
"Mapping between LPD and IPP Protocols" gives some advice to
implementers of gateways between IPP and LPD (Line Printer Daemon)
implementations.
Authors' Addresses
Carl Kugler
IBM Corporation, 003G
6300 Diagonal Hwy
Boulder, CO 80301
Phone: (303) 924-5060
EMail: kugler@us.ibm.com
Tom Hastings, editor
Xerox Corporation
701 S Aviation Blvd. ESAE 242
El Segundo, CA 90245
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Harry Lewis
IBM Corporation
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