RFC 2566
Internet Printing Protocol/1.0: Model and Semantics
4.4.2 uri-security-supported (1setOf type2 keyword) This REQUIRED Printer attribute MUST have the same cardinality (contain the same number of values) as the "printer-uri-supported" attribute. This attribute identifies the security mechanisms used for each URI listed in the "printer-uri-supported" attribute. The "i th" value in "uri-security-supported" corresponds to the "i th" value in "printer-uri-supported" and it describes the security mechanisms used for accessing the Printer object via that URI. The following standard values are defined: 'none': There are no secure communication channel protocols in use for the given URI. 'ssl3': SSL3 [SSL] is the secure communications channel protocol in use for the given URI. Consider the following example. For a single Printer object, an administrator configures the "printer-uri-supported" and "uri- security-supported" attributes as follows: "printer-uri-supported": 'http://acme.com/open-use-printer', ' http://acme.com/restricted-use-printer', ' http://acme.com/private-printer' "uri-security-supported": 'none', 'none', 'ssl3' In this case, one Printer object has three URIs. - For the first URI, 'http://acme.com/open-use-printer', the value 'none' in "uri-security-supported" indicates that there is no secure channel protocol configured to run under HTTP. The name implies that there is no Basic or Digest authentication being used, but it is up to the client to determine that while using HTTP underneath the IPP application protocol. - For the second URI, 'http://acme.com/restricted-use-printer', the value 'none' in "uri-security-supported" indicates that there is no secure channel protocol configured to run under HTTP. In this case, although the name does imply that there is some sort of Basic or Digest authentication being used within HTTP, it is up to the client to determine that while using HTTP and by processing any '401 Unauthorized' HTTP error messages. - For the third URI, 'http://acme.com/private-printer', the value ' ssl3' in "uri-security-supported" indicates that SSL3 is being used to secure the channel. The client SHOULD be prepared to use SSL3 framing to negotiate an acceptable ciphersuite to use while communicating with the Printer object. In this case, the name implies the use of a secure communications channel, but the fact is made explicit by the presence of the 'ssl3' value in
"uri-security-supported". The client does not need to resort to
understanding which security it must use by following naming
conventions or by parsing the URI to determine which security
mechanisms are implied.
It is expected that many IPP Printer objects will be configured to
support only one channel (either configured to use SSL3 access or
not), and will therefore only ever have one URI listed in the
"printer-uri-supported" attribute. No matter the configuration of
the Printer object (whether it has only one URI or more than one
URI), a client MUST supply only one URI in the target "printer-uri"
operation attribute.
4.4.3 printer-name (name(127))
This REQUIRED Printer attribute contains the name of the Printer
object. It is a name that is more end-user friendly than a URI. An
administrator determines a printer's name and sets this attribute to
that name. This name may be the last part of the printer's URI or it
may be unrelated. In non-US-English locales, a name may contain
characters that are not allowed in a URI.
4.4.4 printer-location (text(127))
This Printer attribute identifies the location of the device. This
could include things like: "in Room 123A, second floor of building
XYZ".
4.4.5 printer-info (text(127))
This Printer attribute identifies the descriptive information about
this Printer object. This could include things like: "This printer
can be used for printing color transparencies for HR presentations",
or "Out of courtesy for others, please print only small (1-5 page)
jobs at this printer", or even "This printer is going away on July 1,
1997, please find a new printer".
4.4.6 printer-more-info (uri)
This Printer attribute contains a URI used to obtain more information
about this specific Printer object. For example, this could be an
HTTP type URI referencing an HTML page accessible to a Web Browser.
The information obtained from this URI is intended for end user
consumption. Features outside the scope of IPP can be accessed from
this URI. The information is intended to be specific to this printer
instance and site specific services (e.g. job pricing, services
offered, end user assistance). The device manufacturer may initially
populate this attribute.
4.4.7 printer-driver-installer (uri) This Printer attribute contains a URI to use to locate the driver installer for this Printer object. This attribute is intended for consumption by automata. The mechanics of print driver installation is outside the scope of IPP. The device manufacturer may initially populate this attribute. 4.4.8 printer-make-and-model (text(127)) This Printer attribute identifies the make and model of the device. The device manufacturer may initially populate this attribute. 4.4.9 printer-more-info-manufacturer (uri) This Printer attribute contains a URI used to obtain more information about this type of device. The information obtained from this URI is intended for end user consumption. Features outside the scope of IPP can be accessed from this URI (e.g., latest firmware, upgrades, print drivers, optional features available, details on color support). The information is intended to be germane to this printer without regard to site specific modifications or services. The device manufacturer may initially populate this attribute. 4.4.10 printer-state (type1 enum) This REQUIRED Printer attribute identifies the current state of the device. The "printer-state reasons" attribute augments the "printer-state" attribute to give more detailed information about the Printer in the given printer state. A Printer object need only update this attribute before responding to an operation which requests the attribute; the Printer object NEED NOT update this attribute continually, since asynchronous event notification is not part of IPP/1.0. A Printer NEED NOT implement all values if they are not applicable to a given implementation. The following standard enum values are defined: Value Symbolic Name and Description '3' 'idle': If a Printer receives a job (whose required resources are ready) while in this state, such a job MUST transit into the 'processing' state immediately. If the "printer-state-reasons" attribute contains any reasons, they MUST be reasons that would not prevent a job from transiting into the 'processing' state immediately, e.g., 'toner-low'. Note: if a Printer
controls more than one output device, the above
definition implies that a Printer is 'idle' if at
least one output device is idle.
'4' 'processing': If a Printer receives a job (whose required
resources are ready) while in this state, such a job
MUST transit into the 'pending' state immediately.
Such a job MUST transit into the 'processing' state
only after jobs ahead of it complete. If the
"printer-state-reasons" attribute contains any
reasons, they MUST be reasons that do not prevent the
current job from printing, e.g. 'toner-low'. Note:
if a Printer controls more than one output device, the
above definition implies that a Printer is '
processing' if at least one output device is
processing, and none is idle.
'5' 'stopped': If a Printer receives a job (whose required
resources are ready) while in this state, such a job
MUST transit into the 'pending' state immediately.
Such a job MUST transit into the 'processing' state
only after some human fixes the problem that stopped
the printer and after jobs ahead of it complete
processing. If supported, the "printer-state-reasons"
attribute MUST contain at least one reason, e.g. '
media-jam', which prevents it from either processing
the current job or transitioning a 'pending' job to
the 'processing' state.
Note: if a Printer controls more than one output
device, the above definition implies that a Printer is
'stopped' only if all output devices are stopped.
Also, it is tempting to define 'stopped' as when a
sufficient number of output devices are stopped and
leave it to an implementation to define the sufficient
number. But such a rule complicates the definition of
'stopped' and 'processing'. For example, with this
alternate definition of 'stopped', a job can move from
'pending' to 'processing' without human intervention,
even though the Printer is stopped.
4.4.11 printer-state-reasons (1setOf type2 keyword)
This Printer attribute supplies additional detail about the device's
state.
Each keyword value MAY have a suffix to indicate its level of
severity. The three levels are: report (least severe), warning, and
error (most severe).
- '-report': This suffix indicates that the reason is a "report".
An implementation may choose to omit some or all reports. Some
reports specify finer granularity about the printer state;
others serve as a precursor to a warning. A report MUST contain
nothing that could affect the printed output.
- '-warning': This suffix indicates that the reason is a "warning".
An implementation may choose to omit some or all warnings.
Warnings serve as a precursor to an error. A warning MUST
contain nothing that prevents a job from completing, though in
some cases the output may be of lower quality.
- '-error': This suffix indicates that the reason is an "error".
An implementation MUST include all errors. If this attribute
contains one or more errors, printer MUST be in the stopped
state.
If the implementation does not add any one of the three suffixes, all
parties MUST assume that the reason is an "error".
If a Printer object controls more than one output device, each value
of this attribute MAY apply to one or more of the output devices. An
error on one output device that does not stop the Printer object as a
whole MAY appear as a warning in the Printer's "printer-state-reasons
attribute". If the "printer-state" for such a Printer has a value of
'stopped', then there MUST be an error reason among the values in the
"printer-state-reasons" attribute.
The following standard keyword values are defined:
'other': The device has detected an error other than one listed in
this document.
'none': There are not reasons. This state reason is semantically
equivalent to "printer-state-reasons" without any value.
'media-needed': A tray has run out of media.
'media-jam': The device has a media jam.
'paused': Someone has paused the Printer object. In this state, a
Printer MUST NOT produce printed output, but it MUST perform
other operations requested by a client. If a Printer had been
printing a job when the Printer was paused, the Printer MUST
resume printing that job when the Printer is no longer paused
and leave no evidence in the printed output of such a pause.
'shutdown': Someone has removed a Printer object from service, and
the device may be powered down or physically removed. In this
state, a Printer object MUST NOT produce printed output, and
unless the Printer object is realized by a print server that is
still active, the Printer object MUST perform no other
operations requested by a client, including returning this
value. If a Printer object had been printing a job when it was
shutdown, the Printer NEED NOT resume printing that job when the
Printer is no longer shutdown. If the Printer resumes printing
such a job, it may leave evidence in the printed output of such
a shutdown, e.g. the part printed before the shutdown may be
printed a second time after the shutdown.
'connecting-to-device': The Printer object has scheduled a job on
the output device and is in the process of connecting to a
shared network output device (and might not be able to actually
start printing the job for an arbitrarily long time depending on
the usage of the output device by other servers on the network).
'timed-out': The server was able to connect to the output device
(or is always connected), but was unable to get a response from
the output device.
'stopping': The Printer object is in the process of stopping the
device and will be stopped in a while. When the device is
stopped, the Printer object will change the Printer object's
state to 'stopped'. The 'stopping-warning' reason is never an
error, even for a Printer with a single output device. When an
output-device ceases accepting jobs, the Printer will have this
reason while the output device completes printing.
'stopped-partly': When a Printer object controls more than one
output device, this reason indicates that one or more output
devices are stopped. If the reason is a report, fewer than half
of the output devices are stopped. If the reason is a warning,
fewer than all of the output devices are stopped.
'toner-low': The device is low on toner.
'toner-empty': The device is out of toner.
'spool-area-full': The limit of persistent storage allocated for
spooling has been reached.
'cover-open': One or more covers on the device are open.
'interlock-open': One or more interlock devices on the printer are
unlocked.
'door-open': One or more doors on the device are open.
'input-tray-missing': One or more input trays are not in the
device.
'media-low': At least one input tray is low on media.
'media-empty': At least one input tray is empty.
'output-tray-missing': One or more output trays are not in the
device
'output-area-almost-full': One or more output area is almost full
(e.g. tray, stacker, collator).
'output-area-full': One or more output area is full. (e.g. tray,
stacker, collator)
'marker-supply-low': The device is low on at least one marker
supply. (e.g. toner, ink, ribbon)
'marker-supply-empty: The device is out of at least one marker
supply. (e.g. toner, ink, ribbon)
'marker-waste-almost-full': The device marker supply waste
receptacle is almost full.
'marker-waste-full': The device marker supply waste receptacle is
full.
'fuser-over-temp': The fuser temperature is above normal.
'fuser-under-temp': The fuser temperature is below normal.
'opc-near-eol': The optical photo conductor is near end of life.
'opc-life-over': The optical photo conductor is no longer
functioning.
'developer-low': The device is low on developer.
'developer-empty: The device is out of developer.
'interpreter-resource-unavailable': An interpreter resource is
unavailable (i.e. font, form)
4.4.12 printer-state-message (text(MAX))
This Printer attribute specifies the additional information about the
printer state and printer state reasons in human readable text. If
the Printer object supports this attribute, the Printer object MUST
be able to generate this message in any of the natural languages
identified by the Printer's "generated-natural-language-supported"
attribute (see the "attributes-natural-language" operation attribute
specified in Section 3.1.4.1).
4.4.13 operations-supported (1setOf type2 enum)
This REQUIRED Printer attribute specifies the set of supported
operations for this Printer object and contained Job objects. All
32-bit enum values for this attribute MUST NOT exceed 0x8FFF, since
these values are passed in two octets in each Protocol request
[RFC2565].
The following standard enum and "operation-id" (see section 3.1.2)
values are defined:
Value Operation Name
----------------- -------------------------------------
0x0000 reserved, not used
0x0001 reserved, not used
0x0002 Print-Job
0x0003 Print-URI
0x0004 Validate-Job
0x0005 Create-Job
0x0006 Send-Document
0x0007 Send-URI
0x0008 Cancel-Job
0x0009 Get-Job-Attributes
0x000A Get-Jobs
0x000B Get-Printer-Attributes
0x000C-0x3FFF reserved for future operations
0x4000-0x8FFF reserved for private extensions
This allows for certain vendors to implement private extensions that
are guaranteed to not conflict with future registered extensions.
However, there is no guarantee that two or more private extensions
will not conflict.
4.4.14 charset-configured (charset)
This REQUIRED Printer attribute identifies the charset that the
Printer object has been configured to represent 'text' and 'name'
Printer attributes that are set by the operator, system
administrator, or manufacturer, i.e., for "printer-name" (name),
"printer-location" (text), "printer-info" (text), and "printer-make-
and-model" (text). Therefore, the value of the Printer object's
"charset-configured" attribute MUST also be among the values of the
Printer object's "charset-supported" attribute.
4.4.15 charset-supported (1setOf charset)
This REQUIRED Printer attribute identifies the set of charsets that
the Printer and contained Job objects support in attributes with
attribute syntax 'text' and 'name'. At least the value 'utf-8' MUST
be present, since IPP objects MUST support the UTF-8 [RFC2279]
charset. If a Printer object supports a charset, it means that for
all attributes of syntax 'text' and 'name' the IPP object MUST (1)
accept the charset in requests and return the charset in responses as
needed.
If more charsets than UTF-8 are supported, the IPP object MUST
perform charset conversion between the charsets as described in
Section 3.2.1.2.
4.4.16 natural-language-configured (naturalLanguage)
This REQUIRED Printer attribute identifies the natural language that
the Printer object has been configured to represent 'text' and 'name'
Printer attributes that are set by the operator, system
administrator, or manufacturer, i.e., for "printer-name" (name),
"printer-location" (text), "printer-info" (text), and "printer-make-
and-model" (text). When returning these Printer attributes, the
Printer object MAY return them in the configured natural language
specified by this attribute, instead of the natural language
requested by the client in the "attributes-natural-language" operation attribute. See Section 3.1.4.1 for the specification of the OPTIONAL multiple natural language support. Therefore, the value of the Printer object's "natural-language-configured" attribute MUST also be among the values of the Printer object's "generated-natural- language-supported" attribute. 4.4.17 generated-natural-language-supported (1setOf naturalLanguage) This REQUIRED Printer attribute identifies the natural language(s) that the Printer object and contained Job objects support in attributes with attribute syntax 'text' and 'name'. The natural language(s) supported depends on implementation and/or configuration. Unlike charsets, IPP objects MUST accept requests with any natural language or any Natural Language Override whether the natural language is supported or not. If a Printer object supports a natural language, it means that for any of the attributes for which the Printer or Job object generates messages, i.e., for the "job-state-message" and "printer-state- message" attributes and Operation Messages (see Section 3.1.5) in operation responses, the Printer and Job objects MUST be able to generate messages in any of the Printer's supported natural languages. See section 3.1.4 for the specification of 'text' and ' name' attributes in operation requests and responses. Note: A Printer object that supports multiple natural languages, often has separate catalogs of messages, one for each natural language supported. 4.4.18 document-format-default (mimeMediaType) This REQUIRED Printer attribute identifies the document format that the Printer object has been configured to assume if the client does not supply a "document-format" operation attribute in any of the operation requests that supply document data. The standard values for this attribute are Internet Media types (sometimes called MIME types). For further details see the description of the ' mimeMediaType' attribute syntax in Section 4.1.9. 4.4.19 document-format-supported (1setOf mimeMediaType) This REQUIRED Printer attribute identifies the set of document formats that the Printer object and contained Job objects can support. For further details see the description of the ' mimeMediaType' attribute syntax in Section 4.1.9. 4.4.20 printer-is-accepting-jobs (boolean)
This REQUIRED Printer attribute indicates whether the printer is currently able to accept jobs, i.e., is accepting Print-Job, Print- URI, and Create-Job requests. If the value is 'true', the printer is accepting jobs. If the value is 'false', the Printer object is currently rejecting any jobs submitted to it. In this case, the Printer object returns the 'server-error-not-accepting-jobs' status code. Note: This value is independent of the "printer-state" and "printer- state-reasons" attributes because its value does not affect the current job; rather it affects future jobs. This attribute may cause the Printer to reject jobs when the "printer-state" is 'idle' or it may cause the Printer object to accepts jobs when the "printer-state" is 'stopped'. 4.4.21 queued-job-count (integer(0:MAX)) This RECOMMENDED Printer attribute contains a count of the number of jobs that are either 'pending', 'processing', 'pending-held', or ' processing-stopped' and is set by the Printer object. 4.4.22 printer-message-from-operator (text(127)) This Printer attribute provides a message from an operator, system administrator or "intelligent" process to indicate to the end user information or status of the printer, such as why it is unavailable or when it is expected to be available. 4.4.23 color-supported (boolean) This Printer attribute identifies whether the device is capable of any type of color printing at all, including highlight color. All document instructions having to do with color are embedded within the document PDL (none are external IPP attributes in IPP/1.0). Note: end-users are able to determine the nature and details of the color support by querying the "printer-more-info-manufacturer" Printer attribute. 4.4.24 reference-uri-schemes-supported (1setOf uriScheme) This Printer attribute specifies which URI schemes are supported for use in the "document-uri" operation attribute of the Print-URI or Send-URI operation. If a Printer object supports these optional operations, it MUST support the "reference-uri-schemes-supported" Printer attribute with at least the following schemed URI value: 'ftp': The Printer object will use an FTP 'get' operation as
defined in RFC 2228 [RFC2228] using FTP URLs as defined by
[RFC2396] and[RFC2316].
The Printer object MAY OPTIONALLY support other URI schemes (see
section 4.1.6).
4.4.25 pdl-override-supported (type2 keyword)
This REQUIRED Printer attribute expresses the ability for a
particular Printer implementation to either attempt to override
document data instructions with IPP attributes or not.
This attribute takes on the following values:
- 'attempted': This value indicates that the Printer object
attempts to make the IPP attribute values take precedence over
embedded instructions in the document data, however there is no
guarantee.
- 'not-attempted': This value indicates that the Printer object
makes no attempt to make the IPP attribute values take precedence
over embedded instructions in the document data.
Section 15 contains a full description of how this attribute
interacts with and affects other IPP attributes, especially the
"ipp-attribute-fidelity" attribute.
4.4.26 printer-up-time (integer(1:MAX))
This REQUIRED Printer attribute indicates the amount of time (in
seconds) that this instance of this Printer implementation has been
up and running. This value is used to populate the Job attributes
"time-at-creation", "time-at-processing", and "time-at-completed".
These time values are all measured in seconds and all have meaning
only relative to this attribute, "printer-up-time". The value is a
monotonically increasing value starting from 1 when the Printer
object is started-up (initialized, booted, etc.).
If the Printer object goes down at some value 'n', and comes back up,
the implementation MAY:
1. Know how long it has been down, and resume at some value greater
than 'n', or
2. Restart from 1.
In the first case, the Printer SHOULD not tweak any existing related
Job attributes ("time-at-creation", "time-at-processing", and "time-
at-completed"). In the second case, the Printer object SHOULD reset
those attributes to 0. If a client queries a time-related Job attribute and finds the value to be 0, the client MUST assume that the Job was submitted in some life other than the Printer's current life. 4.4.27 printer-current-time (dateTime) This Printer attribute indicates the current absolute wall-clock time. If an implementation supports this attribute, then a client could calculate the absolute wall-clock time each Job's "time-at- creation", "time-at-processing", and "time-at-completed" attributes by using both "printer-up-time" and this attribute, "printer- current-time". If an implementation does not support this attribute, a client can only calculate the relative time of certain events based on the REQUIRED "printer-up-time" attribute. 4.4.28 multiple-operation-time-out (integer(1:MAX)) This Printer attributes identifies the minimum time (in seconds) that the Printer object waits for additional Send-Document or Send-URI operations to follow a still-open multi-document Job object before taking any recovery actions, such as the ones indicated in section 3.3.1. It is RECOMMENDED that vendors supply a value for this attribute that is between 60 and 240 seconds. An implementation MAY allow a system administrator to set this attribute. If so, the system administrator MAY be able to set values outside this range. 4.4.29 compression-supported (1setOf type3 keyword) This Printer attribute identifies the set of supported compression algorithms for document data. Compression only applies to the document data; compression does not apply to the encoding of the IPP operation itself. The supported values are used to validate the client supplied "compression" operation attributes in Print-Job, Send-Document, and Send-URI requests. Standard values are : 'none': no compression is used. 'deflate': ZIP public domain inflate/deflate) compression technology 'gzip' GNU zip compression technology described in RFC 1952 [RFC1952]. 'compress': UNIX compression technology 4.4.30 job-k-octets-supported (rangeOfInteger(0:MAX))
This Printer attribute specifies the upper and lower bounds of total sizes of jobs in K octets, i.e., in units of 1024 octets. The supported values are used to validate the client supplied "job-k- octets" operation attributes in create requests. The corresponding job description attribute "job-k-octets" is defined in section 4.3.17. 4.4.31 job-impressions-supported (rangeOfInteger(0:MAX)) This Printer attribute specifies the upper and lower bounds for the number of impressions per job. The supported values are used to validate the client supplied "job-impressions" operation attributes in create requests. The corresponding job description attribute "job-impressions" is defined in section 4.3.18. 4.4.32 job-media-sheets-supported (rangeOfInteger(0:MAX)) This Printer attribute specifies the upper and lower bounds for the number of media sheets per job. The supported values are used to validate the client supplied "job-media-sheets" operation attributes in create requests. The corresponding Job attribute "job-media- sheets" is defined in section 4.3.19. 5. Conformance This section describes conformance issues and requirements. This document introduces model entities such as objects, operations, attributes, attribute syntaxes, and attribute values. These conformance sections describe the conformance requirements which apply to these model entities. 5.1 Client Conformance Requirements A conforming client MUST support all REQUIRED operations as defined in this document. For each attribute included in an operation request, a conforming client MUST supply a value whose type and value syntax conforms to the requirements of the Model document as specified in Sections 3 and 4. A conforming client MAY supply any registered extensions and/or private extensions in an operation request, as long as they meet the requirements in Section 6. Otherwise, there are no conformance requirements placed on the user interfaces provided by IPP clients or their applications. For example, one application might not allow an end user to submit multiple documents per job, while another does. One application might first query a Printer object in order to supply a graphical user interface (GUI) dialogue box with supported and default values whereas a different implementation might not.
When sending a request, an IPP client NEED NOT supply any attributes that are indicated as OPTIONALLY supplied by the client. A client MUST be able to accept any of the attribute syntaxes defined in Section 4.1, including their full range, that may be returned to it in a response from a Printer object. In particular for each attribute that the client supports whose attribute syntax is 'text', the client MUST accept and process both the 'textWithoutLanguage' and 'textWithLanguage' forms. Similarly, for each attribute that the client supports whose attribute syntax is 'name', the client MUST accept and process both the 'nameWithoutLanguage' and ' nameWithLanguage' forms. For presentation purposes, truncation of long attribute values is not recommended. A recommended approach would be for the client implementation to allow the user to scroll through long attribute values. A query response may contain attribute groups, attributes, and values that the client does not expect. Therefore, a client implementation MUST gracefully handle such responses and not refuse to inter-operate with a conforming Printer that is returning extended registered or private attributes and/or attribute values that conform to Section 6. Clients may choose to ignore any parameters, attributes, or values that they do not understand. 5.2 IPP Object Conformance Requirements This section specifies the conformance requirements for conforming implementations with respect to objects, operations, and attributes. 5.2.1 Objects Conforming implementations MUST implement all of the model objects as defined in this specification in the indicated sections: Section 2.1 - Printer Object Section 2.2 - Job Object 5.2.2 Operations Conforming IPP object implementations MUST implement all of the REQUIRED model operations, including REQUIRED responses, as defined in this specification in the indicated sections: For a Printer object: Print-Job (section 3.2.1) REQUIRED Print-URI (section 3.2.2) OPTIONAL Validate-Job (section 3.2.3) REQUIRED Create-Job (section 3.2.4) OPTIONAL
Get-Printer-Attributes (section 3.2.5) REQUIRED
Get-Jobs (section 3.2.6) REQUIRED
For a Job object:
Send-Document (section 3.3.1) OPTIONAL
Send-URI (section 3.3.2) OPTIONAL
Cancel-Job (section 3.3.3) REQUIRED
Get-Job-Attributes (section 3.3.4) REQUIRED
Conforming IPP objects MUST support all REQUIRED operation attributes
and all values of such attributes if so indicated in the description.
Conforming IPP objects MUST ignore all unsupported or unknown
operation attributes or operation attribute groups received in a
request, but MUST reject a request that contains a supported
operation attribute that contains an unsupported value.
The following section on object attributes specifies the support
required for object attributes.
5.2.3 IPP Object Attributes
Conforming IPP objects MUST support all of the REQUIRED object
attributes, as defined in this specification in the indicated
sections.
If an object supports an attribute, it MUST support only those values
specified in this document or through the extension mechanism
described in section 5.2.4. It MAY support any non-empty subset of
these values. That is, it MUST support at least one of the specified
values and at most all of them.
5.2.4 Extensions
A conforming IPP object MAY support registered extensions and private
extensions, as long as they meet the requirements specified in
Section 6.
For each attribute included in an operation response, a conforming
IPP object MUST return a value whose type and value syntax conforms
to the requirement of the Model document as specified in Sections 3
and 4.
5.2.5 Attribute Syntaxes An IPP object MUST be able to accept any of the attribute syntaxes defined in Section 4.1, including their full range, in any operation in which a client may supply attributes or the system administrator may configure attributes (by means outside the scope of IPP/1.0). In particular for each attribute that the IPP object supports whose attribute syntax is 'text', the IPP object MUST accept and process both the 'textWithoutLanguage' and 'textWithLanguage' forms. Similarly, for each attribute that the IPP object supports whose attribute syntax is 'name', the IPP object MUST accept and process both the 'nameWithoutLanguage' and 'nameWithLanguage' forms. Furthermore, an IPP object MUST return attributes to the client in operation responses that conform to the syntax specified in Section 4.1, including their full range if supplied previously by a client. 5.3 Charset and Natural Language Requirements All clients and IPP objects MUST support the 'utf-8' charset as defined in section 4.1.7. IPP objects MUST be able to accept any client request which correctly uses the "attributes-natural-language" operation attribute or the Natural Language Override mechanism on any individual attribute whether or not the natural language is supported by the IPP object. If an IPP object supports a natural language, then it MUST be able to translate (perhaps by table lookup) all generated 'text' or 'name' attribute values into one of the supported languages (see section 3.1.4). That is, the IPP object that supports a natural language NEED NOT be a general purpose translator of any arbitrary 'text' or ' name' value supplied by the client into that natural language. However, the object MUST be able to translate (automatically generate) any of its own attribute values and messages into that natural language. 5.4 Security Conformance Requirements Conforming IPP Printer objects MAY support Secure Socket Layer Version 3 (SSL3) [SSL] access, support access without SSL3 or support both means of access. Conforming IPP clients SHOULD support SSL3 access and non-SSL3 access. Note: This client requirement to support both means that conforming IPP clients will be able to inter-operate with any IPP Printer object.
For a detailed discussion of security considerations and the IPP application security profile required for SSL3 support, see section 8. 6. IANA Considerations (registered and private extensions) This section describes how IPP can be extended to allow the following registered and private extensions to IPP: 1. keyword attribute values 2. enum attribute values 3. attributes 4. attribute syntaxes 5. operations 6. attribute groups 7. status codes Extensions registered for use with IPP/1.0 are OPTIONAL for client and IPP object conformance to the IPP/1.0 Model specification. These extension procedures are aligned with the guidelines as set forth by the IESG [RFC2434]. Section 11 describes how to propose new registrations for consideration. IANA will reject registration proposals that leave out required information or do not follow the appropriate format described in Section 11. IPP/1.0 may also be extended by an appropriate RFC that specifies any of the above extensions. 6.1 Typed 'keyword' and 'enum' Extensions IPP allows for 'keyword' and 'enum' extensions (see sections 4.1.2.3 and 4.1.4). This document uses prefixes to the 'keyword' and 'enum' basic attribute syntax type in order to communicate extra information to the reader through its name. This extra information is not represented in the protocol because it is unimportant to a client or Printer object. The list below describes the prefixes and their meaning. "type1": The IPP specification must be revised to add a new keyword or a new enum. No private keywords or enums are allowed. "type2": Implementers can, at any time, add new keyword or enum values by proposing the complete specification to IANA: iana@iana.org
IANA will forward the registration proposal to the IPP
Designated Expert who will review the proposal with a mailing
list that the Designated Expert keeps for this purpose.
Initially, that list will be the mailing list used by the IPP
WG:
ipp@pwg.org
even after the IPP WG is disbanded as permitted by [RFC2434].
The IPP Designated Expert is appointed by the IESG Area Director
responsible for IPP, according to [RFC2434].
When a type2 keyword or enum is approved, the IPP Designated
Expert becomes the point of contact for any future maintenance
that might be required for that registration.
"type3": Implementers can, at any time, add new keyword and enum
values by submitting the complete specification to IANA as for
type2 who will forward the proposal to the IPP Designated
Expert. While no additional technical review is required, the
IPP Designated Expert may, at his/her discretion, forward the
proposal to the same mailing list as for type2 registrations for
advice and comment.
When a type3 keyword or enum is approved by the IPP Designated
Expert, the original proposer becomes the point of contact for
any future maintenance that might be required for that
registration.
For type2 and type3 keywords, the proposer includes the name of the
keyword in the registration proposal and the name is part of the
technical review.
After type2 and type3 enums specifications are approved, the IPP
Designated Expert in consultation with IANA assigns the next
available enum number for each enum value.
IANA will publish approved type2 and type3 keyword and enum
attributes value registration specifications in:
ftp.isi.edu/iana/assignments/ipp/attribute-values/xxx/yyy.txt
where xxx is the attribute name that specifies the initial values and
yyy.txt is a descriptive file name that contains one or more enums or
keywords approved at the same time. For example, if several
additional enums for stapling are approved for use with the
"finishings" attribute (and "finishings-default" and "finishings-
supported" attributes), IANA will publish the additional values in
the file:
ftp.isi.edu/iana/assignments/ipp/attribute-
values/finishings/stapling.txt
Note: Some attributes are defined to be: 'type3 keywords' | 'name'
which allows for attribute values to be extended by a site
administrator with administrator defined names. Such names are not
registered with IANA.
By definition, each of the three types above assert some sort of
registry or review process in order for extensions to be considered
valid. Each higher numbered level (1, 2, 3) tends to be decreasingly
less stringent than the previous level. Therefore, any typeN value
MAY be registered using a process for some typeM where M is less than
N, however such registration is NOT REQUIRED. For example, a type3
value MAY be registered in a type 1 manner (by being included in a
future version of an IPP specification), however, it is NOT REQUIRED.
This specification defines keyword and enum values for all of the
above types, including type3 keywords.
For private (unregistered) keyword extensions, implementers SHOULD
use keywords with a suitable distinguishing prefix, such as "xxx-"
where xxx is the (lowercase) fully qualified company name registered
with IANA for use in domain names [RFC1035]. For example, if the
company XYZ Corp. had obtained the domain name "XYZ.com", then a
private keyword 'abc' would be: 'xyz.com-abc'.
Note: RFC 1035 [RFC1035] indicates that while upper and lower case
letters are allowed in domain names, no significance is attached to
the case. That is, two names with the same spelling but different
case are to be treated as if identical. Also, the labels in a domain
name must follow the rules for ARPANET host names: They must start
with a letter, end with a letter or digit, and have as interior
characters only letters, digits, and hyphen. Labels must be 63
characters or less. Labels are separated by the "." character.
For private (unregistered) enum extension, implementers MUST use
values in the reserved integer range which is 2**30 to 2**31-1.
6.2 Attribute Extensibility Attribute names are type2 keywords. Therefore, new attributes may be registered and have the same status as attributes in this document by following the type2 extension rules. For private (unregistered) attribute extensions, implementers SHOULD use keywords with a suitable distinguishing prefix as described in Section 6.1. IANA will publish approved attribute registration specifications as separate files: ftp.isi.edu/iana/assignments/ipp/attributes/xxx-yyy.txt where "xxx-yyy" is the new attribute name. If a new Printer object attribute is defined and its values can be affected by a specific document format, its specification needs to contain the following sentence: "The value of this attribute returned in a Get-Printer-Attributes response MAY depend on the "document-format" attribute supplied (see Section 3.2.5.1)." If the specification does not, then its value in the Get-Printer- Attributes response MUST NOT depend on the "document-format" supplied in the request. When a new Job Template attribute is registered, the value of the Printer attributes MAY vary with "document-format" supplied in the request without the specification having to indicate so. 6.3 Attribute Syntax Extensibility Attribute syntaxes are like type2 enums. Therefore, new attribute syntaxes may be registered and have the same status as attribute syntaxes in this document by following the type2 extension rules described in Section 6.1. The value codes that identify each of the attribute syntaxes are assigned in the Encoding and Transport specification [RFC2565], including a designated range for private, experimental use. For attribute syntaxes, the IPP Designated Expert in consultation with IANA assigns the next attribute syntax code in the appropriate range as specified in [RFC2565]. IANA will publish approved attribute syntax registration specifications as separate files: ftp.isi.edu/iana/assignments/ipp/attribute-syntaxes/xxx-yyy.txt where 'xxx-yyy' is the new attribute syntax name.
6.4 Operation Extensibility Operations may also be registered following the type2 procedures described in Section 6.1, though major new operations will usually be done by a new standards track RFC that augments this document. For private (unregistered) operation extensions, implementers MUST use the range for the "operation-id" in requests specified in Section 4.4.13 "operations-supported" Printer attribute. For operations, the IPP Designated Expert in consultation with IANA assigns the next operation-id code as specified in Section 4.4.13. IANA will publish approved operation registration specifications as separate files: ftp.isi.edu/iana/assignments/ipp/operations/Xxx-Yyy.txt where "Xxx-Yyy" is the new operation name. 6.5 Attribute Groups Attribute groups passed in requests and responses may be registered following the type2 procedures described in Section 6.1. The tags that identify each of the attribute groups are assigned in [RFC2565]. For attribute groups, the IPP Designated Expert in consultation with IANA assigns the next attribute group tag code in the appropriate range as specified in [RFC2565]. IANA will publish approved attribute group registration specifications as separate files: ftp.isi.edu/iana/assignments/ipp/attribute-group-tags/xxx-yyy- tag.txt where 'xxx-yyy-tag' is the new attribute group tag name. 6.6 Status Code Extensibility Operation status codes may also be registered following the type2 procedures described in Section 6.1. The values for status codes are allocated in ranges as specified in Section 13 for each status code class: "informational" - Request received, continuing process "successful" - The action was successfully received, understood, and accepted "redirection" - Further action must be taken in order to complete the request "client-error" - The request contains bad syntax or cannot be fulfilled
"server-error" - The IPP object failed to fulfill an apparently
valid request
For private (unregistered) operation status code extensions,
implementers MUST use the top of each range as specified in Section
13.
For operation status codes, the IPP Designated Expert in consultation
with IANA assigns the next status code in the appropriate class range
as specified in Section 13. IANA will publish approved status code
registration specifications as separate files:
ftp.isi.edu/iana/assignments/ipp/status-codes/xxx-yyy.txt
where "xxx-yyy" is the new operation status code keyword.
6.7 Registration of MIME types/sub-types for document-formats
The "document-format" attribute's syntax is 'mimeMediaType'. This
means that valid values are Internet Media Types (see Section 4.1.9).
RFC 2045 [RFC2045] defines the syntax for valid Internet media types.
IANA is the registry for all Internet media types.
6.8 Registration of charsets for use in 'charset' attribute values
The "attributes-charset" attribute's syntax is 'charset'. This means
that valid values are charsets names. When a charset in the IANA
registry has more than one name (alias), the name labeled as
"(preferred MIME name)", if present, MUST be used (see Section
4.1.7). IANA is the registry for charsets following the procedures
of [RFC2278].
7. Internationalization Considerations
Some of the attributes have values that are text strings and names
which are intended for human understanding rather than machine
understanding (see the 'text' and 'name' attribute syntaxes in
Sections 4.1.1 and 4.1.2).
In each operation request, the client
- identifies the charset and natural language of the request which
affects each supplied 'text' and 'name' attribute value, and
- requests the charset and natural language for attributes returned
by the IPP object in operation responses (as described in Section
3.1.4.1).
In addition, the client MAY separately and individually identify the Natural Language Override of a supplied 'text' or 'name' attribute using the 'textWithLanguage' and 'nameWithLanguage' technique described section 4.1.1.2 and 4.1.2.2 respectively. All IPP objects MUST support the UTF-8 [RFC2279] charset in all ' text' and 'name' attributes supported. If an IPP object supports more than the UTF-8 charset, the object MUST convert between them in order to return the requested charset to the client according to Section 3.1.4.2. If an IPP object supports more than one natural language, the object SHOULD return 'text' and 'name' values in the natural language requested where those values are generated by the Printer (see Section 3.1.4.1). For Printers that support multiple charsets and/or multiple natural languages in 'text' and 'name' attributes, different jobs may have been submitted in differing charsets and/or natural languages. All responses MUST be returned in the charset requested by the client. However, the Get-Jobs operation uses the 'textWithLanguage' and ' nameWithLanguage' mechanism to identify the differing natural languages with each job attribute returned. The Printer object also has configured charset and natural language attributes. The client can query the Printer object to determine the list of charsets and natural languages supported by the Printer object and what the Printer object's configured values are. See the "charset-configured", "charset-supported", "natural-language- configured", and "generated-natural-language-supported" Printer description attributes for more details. The "charset-supported" attributed identifies the supported charsets. If a charset is supported, the IPP object MUST be capable of converting to and from that charset into any other supported charset. In many cases, an IPP object will support only one charset and it MUST be the UTF-8 charset. The "charset-configured" attribute identifies the one supported charset which is the native charset given the current configuration of the IPP object (administrator defined). The "generated-natural-language-supported" attribute identifies the set of supported natural languages for generated messages; it is not related to the set of natural languages that must be accepted for client supplied 'text' and 'name' attributes. For client supplied ' text' and 'name' attributes, an IPP object MUST accept ALL supplied natural languages. Just because a Printer object is currently
configured to support 'en-us' natural language does not mean that the
Printer object should reject a job if the client supplies a job name
that is in 'fr-ca'.
The "natural-language-configured" attribute identifies the one
supported natural language for generated messages which is the native
natural language given the current configuration of the IPP object
(administrator defined).
Attributes of type 'text' and 'name' are populated from different
sources. These attributes can be categorized into following groups
(depending on the source of the attribute):
1. Some attributes are supplied by the client (e.g., the client
supplied "job-name", "document-name", and "requesting-user-name"
operation attributes along with the corresponding Job object's
"job-name" and "job-originating-user-name" attributes). The IPP
object MUST accept these attributes in any natural language no
matter what the set of supported languages for generated
messages
2. Some attributes are supplied by the system administrator (e.g.,
the Printer object's "printer-name" and "printer-location"
attributes). These too can be in any natural language. If the
natural language for these attributes is different than what a
client requests, then they must be reported using the Natural
Language Override mechanism.
3. Some attributes are supplied by the device manufacturer (e.g.,
the Printer object's "printer-make-and-model" attribute). These
too can be in any natural language. If the natural language for
these attributes is different than what a client requests, then
they must be reported using the Natural Language Override
mechanism.
4. Some attributes are supplied by the operator (e.g., the Job
object's "job-message-from-operator" attribute). These too can
be in any natural language. If the natural language for these
attributes is different than what a client requests, then they
must be reported using the Natural Language Override mechanism.
5. Some attributes are generated by the IPP object (e.g., the Job
object's "job-state-message" attribute, the Printer object's
"printer-state-message" attribute, and the "status-message"
operation attribute). These attributes can only be in one of
the "generated-natural-language-supported" natural languages.
If a client requests some natural language for these attributes
other than one of the supported values, the IPP object SHOULD
respond using the value of the "natural-language-configured"
attribute (using the Natural Language Override mechanism if
needed).
The 'text' and 'name' attributes specified in this version of this
document (additional ones will be registered according to the
procedures in Section 6) are:
Attributes Source
-------------------------- ----------
Operation Attributes
job-name (name) client
document-name (name) client
requesting-user-name (name) client
status-message Job or Printer object
Job Template Attributes:
job-hold-until) client matches administrator-configured
(keyword | name
job-hold-until-default client matches administrator-configured
(keyword | name)
job-hold-until-supported client matches administrator-configured
(keyword | name)
job-sheets client matches administrator-configured
(keyword | name)
job-sheets-default client matches administrator-configured
(keyword | name)
job-sheets-supported client matches administrator-configured
(keyword | name)
media client matches administrator-configured
(keyword | name)
media-default client matches administrator-configured
(keyword | name)
media-supported client matches administrator-configured
(keyword | name)
media-ready client matches administrator-configured
(keyword | name)
Job Description Attributes:
job-name (name) client or Printer object
job-originating-user-name (name) Printer object
job-state-message (text) Job or Printer object
output-device-assigned (name(127)) administrator
job-message-from-operator (text(127)) operator
Printer Description Attributes:
printer-name (name(127)) administrator
printer-location (text(127)) administrator
printer-info (text(127)) administrator
printer-make-and-model (text(127)) administrator or manufacturer
printer-state-message (text) Printer object
printer-message-from-operator (text(127)) operator
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