Internet Printing Protocol WG Hugo Parra
INTERNET-DRAFT Novell, Inc.
<draft-ietf-ipp-indp-method-06.txt> Tom Hastings
Updates: RFC 2910 and 2911 Xerox Corp.
[Target Category: standards track] July 17, 2001
Expires: January 17, 2002
Internet Printing Protocol (IPP):
The 'indp' Delivery Method for Event Notifications and Protocol/1.0
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 documents of the Internet Engineering Task Force (IETF), its
areas, and its working groups. Note that other groups may also
distribute working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress".
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed as
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Abstract
This document describes an extension to the Internet Printing
Protocol/1.0 (IPP) [RFC2566, RFC2565] and IPP/1.1 [RFC2911, RFC2910].
This document specifies the 'indp' Delivery Method and Protocol/1.0
for use with the "IPP Event Notifications and Subscriptions"
specification [ipp-ntfy]. When IPP Notification [ipp-ntfy] is
supported, the Delivery Method defined in this document is one of the
RECOMMENDED Delivery Methods for Printers to support.
This Delivery Method is a simple protocol consisting of a single
operation: the Send-Notifications operation which uses the same
encoding and transport as IPP [RFC2565, RFC2910]. For this Delivery
Method, when an Event occurs, the Printer immediately sends (pushes)
an Event Notification via the Send-Notifications operation to the
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Notification Recipient specified in the Subscription Object. The
Event Notification content consists of Machine Consumable attributes
and a Human Consumable "notify-text" attribute. The Notification
Recipient returns a response to the Printer.
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Table of Contents
1 Introduction.....................................................5
2 Terminology......................................................6
3 Model and Operation..............................................6
4 General Information..............................................7
5 Subscription object attributes..................................10
5.1 Subscription Template Attribute Conformance...................10
5.2 Additional Information about Subscription Template Attributes.10
5.2.1 notify-recipient-uri (uri)..................................10
5.3 Subscription Description Attribute Conformance................10
6 New Values for Existing Printer Description Attributes..........11
6.1 notify-schemes-supported (1setOf uriScheme)...................11
6.2 operations-supported (1setOf type2 enum)......................11
7 Attributes Only in Event Notifications..........................11
8 Operations for Notification.....................................12
8.1 Send-Notifications operation..................................12
8.1.1 Send-Notifications Request..................................12
8.1.2 Send-Notifications Response.................................17
9 Status Codes....................................................18
9.1 Additional Status Codes.......................................18
9.1.1 successful-ok-ignored-notifications (0x0004)................19
9.1.2 client-error-ignored-all-notifications (0x0416).............19
9.2 Status Codes returned in Event Notification Attributes Groups.19
9.2.1 client-error-not-found (0x0406).............................19
9.2.2 successful-ok-but-cancel-subscription (0x0006)..............20
10 Encoding and Transport.........................................20
10.1 Encoding of the Operation Layer..............................20
10.2 Encoding of Transport Layer..................................20
11 Conformance Requirements.......................................20
11.1 Conformance Requirements for Printers........................21
11.2 Conformance Requirements for INDP Notification Recipients....21
12 INDP URL Scheme................................................22
12.1 INDP URL Scheme Applicability and Intended Usage.............22
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12.2 INDP URL Scheme Associated INDP Port.........................22
12.3 INDP URL Scheme Associated MIME Type.........................22
12.4 INDP URL Scheme Character Encoding...........................22
12.5 INDP URL Scheme Syntax in ABNF...............................23
12.5.1 INDP URL Examples..........................................23
12.5.2 INDP URL Comparisons.......................................24
13 IANA Considerations............................................24
13.1 Operation Registrations......................................25
13.2 Additional attribute value registrations for existing attributes
25
13.2.1 Additional values for the "notify-schemes-supported" Printer
attribute..............................................25
13.2.2 Additional values for the "operations-supported" Printer
attribute..............................................26
13.3 Status code Registrations....................................26
14 Internationalization Considerations............................26
15 Security Considerations........................................27
15.1 Security Conformance.........................................27
16 References.....................................................28
17 Author's Addresses.............................................29
18 Summary of Base IPP documents..................................30
19 Full Copyright Statement.......................................32
Tables
Table 1 - Information about the Delivery Method....................8
Table 2 - Operation-id assignments................................11
Table 3 - Attributes in Event Notification Content................15
Table 4 - Additional Attributes in Event Notification Content for Job
Events ........................................................16
Table 5 - Combinations of Events and Subscribed Events for "job-
impressions-completed" ........................................16
Table 6 - Additional Attributes in Event Notification Content for
Printer Events ................................................17
Table 7 - The "event-notification-attributes-tag" value...........20
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1 Introduction
The "IPP Event Notifications and Subscriptions" document [ipp-ntfy]
defines an OPTIONAL extension to Internet Printing Protocol/1.0 (IPP)
[RFC2566, RFC2565] and IPP/1.1 [RFC2911, RFC2910] (for a description
of the base IPP documents, see section 18). That extension defines
operations that a client can perform in order to create Subscription
Objects in a Printer and carry out other operations on them. A
Subscription Object represents a Subscription abstraction. A client
associates Subscription Objects with a particular Job by performing
the Create-Job-Subscriptions operation or by submitting a Job with
subscription information. A client associates Subscription Objects
with the Printer by performing a Create-Printer-Subscriptions
operation. Four other operations are defined for Subscription
Objects: Get-Subscriptions-Attributes, Get-Subscriptions, Renew-
Subscription, and Cancel-Subscription. The Subscription Object
specifies that when one of the specified Events occurs, the Printer
sends an asynchronous Event Notification to the specified
Notification Recipient via the specified Delivery Method (i.e.,
protocol).
The "IPP Event Notifications and Subscriptions" document [ipp-ntfy]
specifies that each Delivery Method is defined in another document.
This document is one such document, and it specifies the 'indp'
Delivery Method. When IPP Notification [ipp-ntfy] is supported, the
Delivery Method defined in this document is one of the RECOMMENDED
Delivery Methods for Printers to support. This Delivery Method is a
simple protocol consisting of a single operation: the Send-
Notifications operation which uses the same encoding and transport as
IPP. This document defines version '1.0' of the protocol.
For the 'indp' Delivery Method, an IPP Printer sends (pushes) a Send-
Notifications operation request containing one or more Event
Notifications to the Notification Recipient specified in the
Subscription Object. The Event Notification content consists of
Machine Consumable attributes and a Human Consumable "notify-text"
attribute.
The Notification Recipient receives the Event Notification as a Send-
Notifications operation, in the same way as an IPP Printer receives
IPP operations. The Notification Recipient returns a response to the
Printer.
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2 Terminology
This section defines the following terms that are used throughout
this document:
This document uses the same terminology as [RFC2911], such as
"client", "Printer", "attribute", "attribute value", "keyword",
"operation", "request", "response", and "support".
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.
Event Notification Attributes Group - The attributes group in a
request that contains Event Notification Attributes in a
request or response.
Other capitalized terms, such as Notification Recipient, Event
Notification, Compound Event Notification, Printer, etc., are
defined in [ipp-ntfy], have the same meanings, and are not
reproduced here.
3 Model and Operation
See [ipp-ntfy] for the description of the Event Notification Model
and Operation. This Delivery Method takes advantage of combining
several Event Notifications into a single Compound Event Notification
that is delivery by a single Send-Notification operation to a single
Notification Recipient.
When creating each Subscription object, the client supplies the
"notify-recipient" (uri) Subscription Template attribute. The
"notify-recipient" attribute specifies both a single Notification
Recipient that is to receive the Notifications when subsequent events
occur and the method for notification delivery that the IPP Printer
is to use. For the Notification Delivery Method defined in this
document, the notification method is 'indp' and the rest of the URI
is the address of the Notification Recipient to which the IPP Printer
will send the Send-Notifications operation.
The 'indp' Notification Delivery Method defined in this document uses
a client/server protocol paradigm. The "client" in this relationship
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is the Printer described in [ipp-ntfy] while the "server" is the
Notification Recipient. The Printer invokes the Send-Notifications
operation to communicate IPP Event Notification contents to the
Notification Recipient. The Notification Recipient only conveys
information to the Printer in the form of responses to the operations
initiated by the Printer.
Printers that implement the 'indp' Notification Delivery Method will
need to include an HTTP client stack while Notification Recipients
that implement this Delivery Method will need to support an HTTP
server stack. See section 10.2 for more details.
If the client wants the Printer to send Event Notifications via the
'indp' Delivery Method, the client MUST choose a value for "notify-
recipient-uri" attribute which conforms to the rules of section
5.2.1.
When an Event occurs, the Printer MUST immediately:
1.Find all pertinent Subscription Objects P according to the rules of
section 9 of [ipp-ntfy], AND
2.Find the subset M of these Subscription Objects P whose "notify-
recipient-uri" attribute has a scheme value of 'indp', AND
3.For each Subscription Object in M, the Printer MUST
a)generate a Send-Notifications request as specified in section
8.1.1 AND
b)send the Send-Notifications request to the Notification
Recipient specified by the address part of the "notify-
recipient-uri" attribute value (see section 5.2.1).
If several events occur sufficiently close to one another for the
same or different Subscription objects, but with the same
Notification Recipient, the Printer MAY combine them into a single
Send-Notifications request using a separate Event Notification
Attributes group for each event (see section 8.1.1).
4 General Information
If a client or Printer supports this Delivery Method, Table 1 lists
its characteristics.
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Table 1 - Information about the Delivery Method
Document Method conformance 'indp' realization
requirement
1. What is the URL scheme name indp
for the Delivery Method?
2. Is the Delivery Method is
REQUIRED, RECOMMENDED, or
OPTIONAL for an IPP Printer to
support? RECOMMENDED
3. What transport and delivery
protocol does the Printer use complete HTTP/1.1 stack
to deliver the Event [RFC2616]
Notification content, i.e.,
what is the entire network
stack? A Printer MUST support a
4. Can several Event A Printer implementation MAY
Notifications be combined into combine several Event
a Compound Event Notification? Notifications into a single
Event Notifications request as
separate Event Notification
Attributes Groups, see section
8.1.1
5. Is the Delivery Method This Delivery Method is a push.
initiated by the Notification
Recipient (pull), or by the
Printer (push)?
6. Is the Event Notification Machine Consumable with the
content Machine Consumable or "notify-text" attribute being
Human Consumable? Human Consumable
7. What section in this document The representation and encoding
answers the following is the same as IPP. See
question? For a Machine section 8.1.1
Consumable Event Notification,
what is the representation and
encoding of values defined in
section 9.1 of [ipp-ntfy] and
the conformance requirements
thereof? For a Human
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Document Method conformance 'indp' realization
requirement
thereof? For a Human
Consumable Event Notification,
what is the representation and
encoding of pieces of
information defined in section
9.2 of [ipp-ntfy] and the
conformance requirements
thereof?
8. What are the latency and
reliability of the transport itself (see [RFC2911]).
and delivery protocol? Same as for IPP/1.0 or IPP/1.1
9. What are the security aspects See section 15
of the transport and delivery
protocol, e.g., how it is
handled in firewalls?
10. What are the content length They are the same as for
restrictions? IPP/1.0 and IPP/1.1 itself (see
[RFC2911]).
11. What are the additional values A new Event Notifications
or pieces of information that attribute group (see section
a Printer sends in an Event 10.1) and additional status
Notification and the codes for use in the response
conformance requirements (see section 9)
thereof?
12. What are the additional None
Subscription Template and/or
Subscription Description
attributes and the conformance
requirements thereof?
13. What are the additional None
Printer Description attributes
and the conformance
requirements thereof?
The remaining sections of this document parallel the sections of
[ipp-ntfy].
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5 Subscription object attributes
This section defines the Subscription object conformance requirements
for Printers.
5.1 Subscription Template Attribute Conformance
The 'indp' Delivery Method has the same conformance requirements for
Subscription Template attributes as defined in [ipp-ntfy]. The
'indp' Delivery Method does not define any addition Subscription
Template attributes.
5.2 Additional Information about Subscription Template Attributes
This section defines additional information about Subscription
Template attributes defined in [ipp-ntfy].
5.2.1 notify-recipient-uri (uri)
This section describes the syntax of the value of this attribute for
the 'indp' Delivery Method. The syntax for values of this attribute
for other Delivery Method is defined in other Delivery Method
Documents.
In order to support the 'indp' Delivery Method and Protocol, the
Printer MUST support the following syntax:
The 'indp://' URI scheme. The remainder of the URI indicates
the host name or host address (and optional path) of the
Notification Recipient that is to receive the Send-
Notification operation. See section 12 for a complete
definition of the syntax of the INDP URL.
5.3 Subscription Description Attribute Conformance
The 'indp' Delivery Method has the same conformance requirements for
Subscription Description attributes as defined in [ipp-ntfy]. The
'indp' Delivery Method does not define any addition Subscription
Description attributes.
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6 New Values for Existing Printer Description Attributes
This Delivery Method does not define any additional Printer
Description attribute from those defined in [ipp-ntfy]. However, it
does define additional values for existing Printer Description
attributes defined in [ipp-ntfy]. This section defines those
additional values.
6.1 notify-schemes-supported (1setOf uriScheme)
The following value of the "notify-schemes-supported" Printer
attribute (see [ipp-ntfy] section 5.3.1) is added in order to support
the new Delivery Method defined in this document:
'indp' - The IPP Notification Delivery Method defined in this
document.
6.2 operations-supported (1setOf type2 enum)
Table 2 lists the value of the "operation-id" operation parameter
(see [RFC2911]) and the value of the "operations-supported" Printer
Description attribute (see [RFC2911]) added in order to support the
new operation defined in this document. The operation-id is assigned
in the same name space as other operations that a Printer supports.
However, a Printer MUST NOT include this value in its "operations-
supported" attribute unless it can accept the Send-Notifications
request.
Table 2 - Operation-id assignments
Value Operation Name
0x001D Send-Notifications
7 Attributes Only in Event Notifications
No additional attributes are defined only for use in Event
Notifications besides those defined in [ipp-ntfy].
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8 Operations for Notification
This section defines the operation for Event Notification using the
'indp' Delivery Method.
There is only one operation defined: Send-Notifications. Section
6.2 assigns of the "operation-id" for the Send-Notifications
operation and the following section defined the operation.
8.1 Send-Notifications operation
This REQUIRED operation allows a Printer to send one or more Event
Notifications to a Notification Recipient using HTTP.
The Printer composes the information defined for an IPP Notification
[ipp-ntfy] and sends it using the Send-Notifications operation to the
Notification Recipient supplied in the Subscription object. The
ordering of separate Send-Notifications operations that a Printer
sends MUST follow the "Event Notification Ordering" requirements in
[ipp-ntfy] section 9.
The Send-Notifications operation uses the operations model defined by
IPP [RFC2566]. This includes, the use of a URI as the identifier for
the target of each operation, the inclusion of a version number,
operation-id, and request-id in each request, and the definition of
attribute groups. The Send-Notifications operation uses the Operation
Attributes group, but currently has no need for the Unsupported
Attributes, Printer Object Attributes, and Job-Object Attributes
groups. However, it uses a new attribute group, the Event
Notification Attributes group.
The Notification Recipient MUST accept the request in any state.
There is no state defined for the Notification Recipient for this
Delivery Method.
Access Rights: Notification Recipient MAY enforce access rights. If
the Printer receives a rejection with these status codes: 'client-
error-forbidden', 'client-error-not-authenticated', or 'client-error-
not-authorized' status code , the Printer SHOULD cancel the
subscription.
8.1.1 Send-Notifications Request
Every operation request MUST contains the following parameters (see
[RFC2911] section 3.1.1):
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- a "version-number" '1.0' - the version of the 'indp'
protocol is '1.0'.
- an "operation-id" - the value defined in Table 2
- a "request-id" - the request id (see [RFC2911] section 3.1.2).
The following groups of attributes MUST be part of the Send-
Notifications Request:
Group 1: Operation Attributes
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as defined in [RFC2911] section 3.1.4.1.
The Printer MUST use the values of "notify-charset" and
"notify-natural-language", respectively, from one Subscription
Object associated with the Event Notifications in this request.
Normally, there is only one matched Subscription Object, or the
value of the "notify-charset" and "notify-natural-language"
attributes is the same in all Subscription Objects. If not, the
Printer MUST pick one Subscription Object from which to obtain
the value of these attributes. The algorithm for picking the
Subscription Object is implementation dependent. The choice of
natural language is not critical because 'text' and 'name'
values can override the "attributes-natural-language" Operation
attribute. The Printer's choice of charset is critical because
a bad choice may leave it unable to send some 'text' and 'name'
values accurately.
Target:
A copy of the Subscription object's "notify-recipient-uri"
(uri) attribute which is the target of this operation as
described in [RFC2911] section 3.1.5, i.e., the URI of the
'indp' Notification Recipient (see section 5.2.1).
Group 2 to N: Event Notification Attributes
In each group 2 to N, each attribute is encoded using the IPP
rules for encoding attributes [RFC2910] and the attributes
within a group MAY be encoded in any order. Note: the Get-Jobs
response in [RFC2911] acts as a model for encoding multiple
groups of attributes. The entire request is considered a
single Compound Event Notification and MUST follow the "Event
Notification Ordering" requirements for Event Notifications
within a Compound Event Notification specified in [ipp-ntfy]
section 9.
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Each Event Notification Group MUST contain all of attributes
specified in [ipp-ntfy] section 9.1 ("Content of Machine
Consumable Event Notifications") with exceptions denoted by
asterisks in the tables below.
The tables below are copies of the tables in [ipp-ntfy] section
9.1 ("Content of Machine Consumable Event Notifications")
except that each cell in the "Sends" column is a "MUST".
For an Event Notification for all Events, the Printer sends the
following attributes.
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Table 3 - Attributes in Event Notification Content
Source Value Sends Source Object
notify-subscription-id (integer(1:MAX)) MUST Subscription
notify-printer-uri (uri) MUST Subscription
notify-subscribed-event (type2 keyword) MUST Event
Notification
printer-up-time (integer(MIN:MAX)) MUST Printer
printer-current-time (dateTime) MUST * Printer
notify-sequence-number (integer (0:MAX)) MUST Subscription
notify-charset (charset) MUST Subscription
notify-natural-language (naturalLanguage) MUST Subscription
notify-user-data (octetString(63)) MUST ** Subscription
notify-text (text (MAX)) MUST Event
Notification
attributes from the "notify-attributes" MUST *** Printer
attribute, if any
attributes from the "notify-attributes" MUST *** Job
attribute, if any
attributes from the "notify-attributes" MUST *** Subscription
attribute, if any
* The Printer MUST send "printer-current-time" if and only if
it supports the "printer-current-time" attribute on the Printer
object.
** If the associated Subscription Object does not contain a
"notify-user-data" attribute, the Printer MUST send an octet-
string of length 0.
*** If the "notify-attributes" attribute is present on the
Subscription Object, the Printer MUST send all attributes
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specified by the "notify-attributes" attribute. Note: if the
Printer doesn't support the "notify-attributes" attribute, it
is not present on the associated Subscription Object and the
Printer does not send any client-requested attributes.
For Event Notifications for Job Events, the Printer sends the
following additional attributes shown in Table 4.
Table 4 - Additional Attributes in Event Notification Content for
Job Events
Source Value Sends Source
Object
job-id (integer(1:MAX)) MUST Job
job-state (type1 enum) MUST Job
job-state-reasons (1setOf type2 keyword) MUST Job
job-impressions-completed (integer(0:MAX)) MUST * Job
* The Printer MUST send the "job-impressions-completed"
attribute in an Event Notification only for the combinations of
Events and Subscribed Events shown in Table 5.
Table 5 - Combinations of Events and Subscribed Events for "job-
impressions-completed"
Job Event Subscribed Job Event
'job-progress' 'job-progress'
'job-completed' 'job-completed'
'job-completed' 'job-state-changed'
For Event Notification for Printer Events, the Printer sends
the following additional attributes shown in Table 6.
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Table 6 - Additional Attributes in Event Notification Content for
Printer Events
Source Value Sends Source Object
printer-state (type1 enum) MUST Printer
printer-state-reasons (1setOf type2 keyword) MUST Printer
printer-is-accepting-jobs (boolean) MUST Printer
8.1.2 Send-Notifications Response
The Notification Recipient MUST return (to the client which is the
Printer) the following sets of attributes as part of a Send-
Notifications response:
Every operation response contains the following REQUIRED parameters
(see [RFC2911] section 3.1.1}:
- a "version-number"
- a "status-code"
- the "request-id" that was supplied in the corresponding request
Group 1: Operation Attributes
Status Message:
As defined in [RFC2911].
The Notification Recipient can return any status codes defined
in [RFC2911] and section 9.1 that applies to all of the Event
Notification Attribute groups. The following is a description
of the important status codes:
'successful-ok': the Notification Recipient received all of
the Event Notification Attribute Groups and was expecting
each of them.
'successful-ok-ignored-notifications': the Notification
Recipient was able to consume some, but not all of the
Event Notification Attributes Groups sent. The Event
Notification Attributes Groups with a "notify-status-
code" attribute are the ones that were ignored or are to
be canceled.
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'client-error-ignored-all-notifications': the Notification
Recipient was unable to consume any of the Event
Notification Attributes Groups sent. The Event
Notification Attributes Groups with a "notify-status-
code" attribute are the ones that were ignored or are to
be canceled.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as defined in [RFC2911] section 3.1.4.1.
Group 2 to N: Notification Attributes
These groups MUST be returned if and only if the "status-code"
parameter returned in Group 1 is anything but the 'successful-ok'
status code.
"notify-status-code" (type2 enum)
Indicates whether the Notification Recipient was able to
consume the n-th Notification Report as follows:
'successful-ok' - this Event Notification Attribute Group
was consumed
'client-error-not-found' - this Event Notification
Attribute Group was not able to be consumed. The Printer
MUST cancel the Subscription and MUST NOT attempt to send
any further Event Notifications from the associated
Subscription object.
'successful-ok-but-cancel-subscription' - the Event
Notification Attribute Group was consumed, but the
Notification Recipient wishes to cancel the Subscription
object. The Printer MUST cancel the Subscription and
MUST NOT attempt to send any further Event Notifications
from the associated Subscription object.
9 Status Codes
This section lists status codes whose meaning have been extended
and/or defined for returning in Event Notification Attribute Groups
as the value of the "notify-status-code" operation attribute. The
code values are allocated in the same space as the status codes in
[RFC2911].
9.1 Additional Status Codes
The following status codes are defined as extensions for Notification
and are returned as the value of the "status-code" parameter in the
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Operation Attributes Group of a response (see [RFC2911] section
3.1.6.1). Operations in this document can also return the status
codes defined in section 13 of [RFC2911]. The 'successful-ok' status
code is an example of such a status code.
9.1.1 successful-ok-ignored-notifications (0x0004)
The Notification Recipient was able to consume some, but not all, of
the Event Notifications Attributes Groups sent by the Printer in the
Send-Notifications request. See section 8.1.2 for further details.
9.1.2 client-error-ignored-all-notifications (0x0416)
The Notification Recipient was unable to consume any of the Event
Notification Attributes Groups sent by the Printer. The Event
Notification Attributes Groups with a "notify-status-code" attribute
are the ones that were ignored or are to be canceled. The Printer
MAY remove subscriptions for future events which this client was
unable to consume.
9.2 Status Codes returned in Event Notification Attributes Groups
This section contains values of the "notify-status-code" attribute
that the Notification Recipient returns in a Event Notification
Attributes Group in a response when the corresponding Event
Notification Attributes Group in the request:
1.was not consumed OR
2.was consumed, but the Notification Recipient wants to cancel the
corresponding Subscription object
The following sections are ordered in decreasing order of importance
of the status-codes.
9.2.1 client-error-not-found (0x0406)
This status code is defined in [RFC2911]. This document extends its
meaning and allows it to be returned in an Event Notification
Attributes Group of a response.
The Notification Recipient was unable to consume this Event
Notification Attributes Group because it was not expected. See
section 8.1.2 for further details.
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9.2.2 successful-ok-but-cancel-subscription (0x0006)
The Notification Recipient was able to consume this Event
Notification Attributes Group that the Printer sent, but wants the
corresponding Subscription object to be canceled none-the-less. See
section 8.1.2 for further details.
10 Encoding and Transport
This section defines the encoding and transport used by the 'indp'
Delivery Method.
10.1 Encoding of the Operation Layer
The 'indp' Delivery Method uses the IPP operation layer encoding
described in [RFC2910] and the Event Notification Attributes Group
tag allocated by [ipp-ntfy] as shown in Table 7:
Table 7 - The "event-notification-attributes-tag" value
Tag Value (Hex) Meaning
0x07 "event-notification-attributes-tag"
10.2 Encoding of Transport Layer
The 'indp' Notification Delivery Method uses the IPP transport layer
encoding described in [RFC2910].
It is REQUIRED that an 'indp' Notification Recipient implementation
support HTTP over the IANA-assigned well known system port assigned
to the 'indp' Delivery Method as its default port by IANA (see
section 13), though a Notification Recipient implementation MAY
support HTTP over some other port as well.
11 Conformance Requirements
This section defines conformance requirements for Printers and
Notification Recipients.
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11.1 Conformance Requirements for Printers
The 'indp' Delivery Method is RECOMMENDED for a Printer to support.
IPP Printers that conform to this specification:
1.MUST meet the conformance requirements defined in [ipp-ntfy].
2.MUST support the conformance requirements for Subscription object
attributes defined in section 5, including the syntax for the
"notify-recipient-uri" Subscription Object attribute defined in
section 5.2.1.
3.MUST support the conformance requirements for Printer Description
object attributes defined in section 6.
4.MUST support the 'indp' protocol by sending Event Notifications
using the Send-Notifications operation defined in section 8.1.
5.MUST send INDP URLs (e.g., in the "notify-recipient-uri" attribute
in 'Send-Notifications') that conform to the ABNF specified in
section 12.5 of this document;
6.MUST send the Send-Notifications operation via the port specified
in the INDP URL (if present) or otherwise via the IANA-assigned
well-known system port xxx [TBA by IANA];
7.MUST convert INDP URLs for use in the Send-Notifications operation
to their corresponding HTTP URL forms for use in the HTTP layer by
the same rules used to convert IPP URLs to their corresponding
HTTP URL forms (see section 5 'IPP URL Scheme' in [RFC2910]).
11.2 Conformance Requirements for INDP Notification Recipients
INDP Notification Recipients that conform to this specification:
1.MUST accept Send-Notifications requests and return Send-
Notifications responses as defined in sections 8 and 9.
2.SHOULD reject received INDP URLs in "application/ipp" request
bodies (e.g., in the "notify-recipient-uri" attribute in 'Send-
Notifications') that do not conform to the ABNF for INDP URLs
specified in section 12.5 of this document;
3.MUST listen for INDP operations on IANA-assigned well-known system
port xxx [TBA by IANA], unless explicitly configured by system
administrators or site policies;
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4.SHOULD NOT listen for INDP operations on any other port, unless
explicitly configured by system administrators or site policies.
12 INDP URL Scheme
12.1 INDP URL Scheme Applicability and Intended Usage
This section is intended for use in registering the "indp" URL scheme
with IANA and fully conforms to the requirements in [RFC2717]. This
document defines the "indp" URL (Uniform Resource Locator) scheme for
specifying the location of an INDP Notification Recipient object
which implements IPP Notification Delivery Protocol (INDP) specified
in this document.
The intended usage of the "indp" URL scheme is COMMON.
12.2 INDP URL Scheme Associated INDP Port
All INDP URLs which do NOT explicitly specify a port MUST be used
over IANA-assigned well-known system port xxx [TBA by IANA] for the
INDP protocol.
See: IANA Port Numbers Registry [IANA-PORTREG].
12.3 INDP URL Scheme Associated MIME Type
All INDP protocol operations (requests and responses) MUST be
conveyed in an "application/ipp" MIME media type as registered in
[IANA-MIMEREG]. INDP URLs MUST refer to INDP Notification Recipient
objects which support this "application/ipp" MIME media type.
See: IANA MIME Media Types Registry [IANA-MIMEREG].
12.4 INDP URL Scheme Character Encoding
The INDP URL scheme defined in this document is based on the ABNF for
the HTTP URL scheme defined in HTTP/1.1 [RFC2616], which is derived
from the URI Generic Syntax [RFC2396] and further updated by
[RFC2732] and [RFC2373] (for IPv6 addresses in URLs). The INDP URL
scheme is case-insensitive in the 'scheme' and 'host' (host name or
host address) part; however the 'abs_path' part is case-sensitive, as
in [RFC2396]. Code points outside [US-ASCII] MUST be hex escaped by
the mechanism specified in [RFC2396].
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12.5 INDP URL Scheme Syntax in ABNF
The IPP protocol places a limit of 1023 octets (NOT characters) on
the length of a URI (see section 4.1.5 'uri' in [RFC2911]). An INDP
Notification Recipient MUST return 'client-error-request-value-too-
long' (see section 13.1.4.10 in [RFC2911]) when a URI received in a
request is too long.
Note: INDP Notification Recipients ought to be cautious about
depending on URI lengths above 255 bytes, because some older client
or proxy implementations might not properly support these lengths.
INDP URLs MUST be represented in absolute form. Absolute URLs always
begin with a scheme name followed by a colon. For definitive
information on URL syntax and semantics, see "Uniform Resource
Identifiers (URI): Generic Syntax and Semantics" [RFC2396]. This
specification adopts the definitions of "port", "host", "abs_path",
and "query" from [RFC2396], as updated by [RFC2732] and [RFC2373]
(for IPv6 addresses in URLs).
The INDP URL scheme syntax in ABNF is as follows:
indp_URL = "indp:" "//" host [ ":" port ] [ abs_path [ "?" query ]]
If the port is empty or not given, IANA-assigned well-known system
port xxx [TBA by IANA] is assumed. The semantics are that the
identified resource (see section 5.1.2 of [RFC2616]) is located at
the INDP Notification Recipient listening for HTTP connections on
that port of that host, and the Request-URI for the identified
resource is 'abs_path'.
Note: The use of IP addresses in URLs SHOULD be avoided whenever
possible (see [RFC1900]).
If the 'abs_path' is not present in the URL, it MUST be given as "/"
when used as a Request-URI for a resource (see section 5.1.2 of
[RFC2616]). If a proxy receives a host name which is not a fully
qualified domain name, it MAY add its domain to the host name it
received. If a proxy receives a fully qualified domain name, the
proxy MUST NOT change the host name.
12.5.1 INDP URL Examples
The following are examples of valid INDP URLs for Notification
Recipient objects (using DNS host names):
indp://abc.com
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indp://abc.com/listener
Note: The use of IP addresses in URLs SHOULD be avoided whenever
possible (see [RFC1900]).
The following literal IPv4 addresses:
192.9.5.5 ; IPv4 address in IPv4 style
186.7.8.9 ; IPv4 address in IPv4 style
are represented in the following example INDP URLs:
indp://192.9.5.5/listener
indp://186.7.8.9/listeners/tom
The following literal IPv6 addresses (conformant to [RFC2373]):
::192.9.5.5 ; IPv4 address in IPv6 style
::FFFF:129.144.52.38 ; IPv4 address in IPv6 style
2010:836B:4179::836B:4179 ; IPv6 address per RFC 2373
are represented in the following example INDP URLs:
indp://[::192.9.5.5]/listener
indp://[::FFFF:129.144.52.38]/listener
indp://[2010:836B:4179::836B:4179]/listeners/tom
12.5.2 INDP URL Comparisons
When comparing two INDP URLs to decide if they match or not, the
comparer MUST use the same rules as those defined for HTTP URI
comparisons in [RFC2616], with the sole following exception:
? A port that is empty or not given MUST be treated as equivalent
to the well-known system port xxx [TBA by IANA] for that INDP
URL;
13 IANA Considerations
IANA shall register the indp URL scheme as defined in section 12
according to the procedures of [RFC2717] and assign a well-known
system port.
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The rest of this section contains the exact information for IANA to
add to the IPP Registries according to the procedures defined in RFC
2911 [RFC2911] section 6.
Note to RFC Editors: Replace RFC NNNN below with the RFC number
for this document, so that it accurately reflects the content of
the information for the IANA Registry.
13.1 Operation Registrations
The following table lists the operation defined in this document.
This is to be registered according to the procedures in RFC 2911
[RFC2911] section 6.4.
Operations: Ref.
Section:
Send-Notifications operation RFC NNNN 8.1
The resulting operation registration will be published in the
ftp://ftp.iana.org/in-notes/iana/assignments/ipp/operations/
area.
13.2 Additional attribute value registrations for existing attributes
This section lists additional attribute value registrations for use
with existing attributes defined in other documents.
13.2.1 Additional values for the "notify-schemes-supported" Printer
attribute
The following table lists the uriScheme value defined in this
document as an additional uriScheme value for use with the "notify-
schemes-supported" Printer attribute defined in [ipp-ntfy]. This is
to be registered according to the procedures in RFC 2911 [RFC2911]
section 6.1.
uriScheme Attribute Values: Ref. Section:
indp RFC NNNN 6.1
The resulting URI scheme attribute value registration will be
published in the
ftp://ftp.iana.org/in-notes/iana/assignments/ipp/attribute-
values/notify-schemes-supported/
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area.
13.2.2 Additional values for the "operations-supported" Printer
attribute
The following table lists the enum attribute value defined in this
document as an additional type2 enum value for use with the
"operations-supported" Printer attribute defined in [RFC2911]. This
is to be registered according to the procedures in RFC 2911 [RFC2911]
section 6.1.
type2 enum Attribute Values: Value Ref. Section:
Send-Notifications 0x001D RFC NNNN 6.2
The resulting enum attribute value registration will be published in
the
ftp://ftp.iana.org/in-notes/iana/assignments/ipp/attribute-
values/operations-supported/
area.
13.3 Status code Registrations
The following table lists all the status codes defined in this
document. These are to be registered according to the procedures in
RFC 2911 [RFC2911] section 6.6.
Status codes: Ref. Section:
successful-ok-ignored-notifications (0x0004) RFC NNNN 9.1.1
client-error-ignored-all-notifications (0x0416) RFC NNNN 9.1.2
Status Codes in Event Notification Attributes Groups:
client-error-not-found (0x0406) RFC NNNN 9.2.1
successful-ok-but-cancel-subscription (0x0006) RFC NNNN 9.2.2
The resulting status code registrations will be published in the
ftp://ftp.iana.org/in-notes/iana/assignments/ipp/status-codes/
area.
14 Internationalization Considerations
When the client requests Human Consumable form by supplying the
"notify-text-format" operation attribute (see [ipp-ntfy]), the IPP
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Printer (or any Notification Service that the IPP Printer might be
configured to use) supplies and localizes the text value of the
"human-readable-report" attribute in the Notification according to
the charset and natural language requested in the notification
subscription.
15 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.
The Notification Recipient can cancel unwanted Subscriptions created
by other parties without having to be the owner of the subscription
by returning the 'successful-ok-but-cancel-subscription' status code
in the Send-Notifications response returned to the Printer.
15.1 Security Conformance
Printers (client) MAY support Digest Authentication [RFC2617]. If
Digest Authentication is supported, then MD5 and MD5-sess MUST be
supported, but the Message Integrity feature NEED NOT be supported.
Notification Recipient (server) MAY support Digest Authentication
[RFC2617]. If Digest Authentication is supported, then MD5 and MD5-
sess MUST be supported, but the Message Integrity feature NEED NOT be
supported.
Notification Recipients MAY support TLS for client authentication,
server authentication and operation privacy. If a Notification
Recipient supports TLS, it MUST support the
TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA cipher suite as mandated by RFC
2246 [RFC2246]. All other cipher suites are OPTIONAL. Notification
recipients MAY support Basic Authentication (described in HTTP/1.1
[RFC2616]) for client authentication if the channel is secure. TLS
with the above mandated cipher suite can provide such a secure
channel.
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16 References
[ipp-iig]
Hastings, T., Manros, C., Kugler, K, Holst H., Zehler, P.,
"Internet Printing Protocol/1.1: draft-ietf-ipp-implementers-
guide-v11-03.txt, work in progress, July 17, 2001
[ipp-ntfy]
Isaacson, S., Martin, J., deBry, R., Hastings, T., Shepherd, M.,
Bergman, R., "Internet Printing Protocol/1.1: IPP Event
Notifications and Subscriptions", <draft-ietf-ipp-not-spec-07.txt>,
July 17, 2001.
[IANA-MIMEREG]
IANA MIME Media Types Registry. ftp://ftp.iana.org/in-
notes/iana/assignments/media-types/
[IANA-PORTREG]
IANA Port Numbers Registry. ftp://ftp.iana.org/in-
notes/iana/assignments/port-numbers
[RFC1900]
B. Carpenter, Y. Rekhter. Renumbering Needs Work, RFC 1900,
February 1996.
[RFC2026]
S. Bradner, "The Internet Standards Process -- Revision 3", RFC
2026, October 1996.
[RFC2373]
R. Hinden, S. Deering. IP Version 6 Addressing Architecture, RFC
2373, July 1998.
[RFC2396]
Berners-Lee, T. et al. Uniform Resource Identifiers (URI): Generic
Syntax, RFC 2396, August 1998
[RFC2565]
Herriot, R., Butler, S., Moore, P., and R. Turner, "Internet
Printing Protocol/1.0: Encoding and Transport", RFC 2565, April
1999.
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[RFC2566]
R. deBry, T. Hastings, R. Herriot, S. Isaacson, and P. Powell,
"Internet Printing Protocol/1.0: Model and Semantics", RFC 2566,
April 1999.
[RFC2567]
Wright, D., "Design Goals for an Internet Printing Protocol", RFC
2567, April 1999.
[RFC2568]
Zilles, S., "Rationale for the Structure and Model and Protocol for
the Internet Printing Protocol", RFC 2568, April 1999.
[RFC2569]
Herriot, R., Hastings, T., Jacobs, N., Martin, J., "Mapping between
LPD and IPP Protocols", RFC 2569, April 1999.
[RFC2616]
R. Fielding, J. Gettys, J. Mogul, H. Frystyk, L. Masinter, P.
Leach, T. Berners-Lee, "Hypertext Transfer Protocol - HTTP/1.1",
RFC 2616, June 1999.
[RFC2617]
J. Franks, P. Hallam-Baker, J. Hostetler, S. Lawrence, P. Leach, A.
Luotonen, L. Stewart, "HTTP Authentication: Basic and Digest Access
Authentication", RFC 2617, June 1999.
[RFC2717]
R. Petke and I. King, "Registration Procedures for URL Scheme
Names", RFC 2717, November 1999.
[RFC2732]
R. Hinden, B. Carpenter, L. Masinter. Format for Literal IPv6
Addresses in URL's, RFC 2732, December 1999.
[RFC2910]
Herriot, R., Butler, S., Moore, P., Tuner, R., "Internet Printing
Protocol/1.1: Encoding and Transport", RFC 2910, September 2001.
[RFC2911]
R. deBry, T. Hastings, R. Herriot, S. Isaacson, P. Powell,
"Internet Printing Protocol/1.1: Model and Semantics", RFC 2911,
September 2001.
17 Author's Addresses
Hugo Parra
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Novell, Inc.
1800 South Novell Place
Provo, UT 84606
Phone: 801-861-3307
Fax: 801-861-2517
e-mail: hparra@novell.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
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.
18 Summary of Base IPP documents
The base 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]
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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 [RFC2566, RFC2565]. A few OPTIONAL operator
operations have been added to IPP/1.1 [RFC2911, RFC2910].
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.
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 a message body over HTTP whose Content-Type is
"application/ipp". This document defines the 'ipp' 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.
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The "Internet Printing Protocol (IPP): 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 by creating a
Subscription Object 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.
19 Full Copyright Statement
Copyright (C) The Internet Society (2001). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
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