INTERNET-DRAFT Robert Herriot (editor)
Sun Microsystems
<draft-ietf-ipp-protocol-06.txt> Sylvan Butler
Hewlett-Packard
Paul Moore
Microsoft
Randy Turner
Sharp Labs
June 30, 1998
Internet Printing Protocol/1.0: Encoding and Transport
Status of this Memo
This document is an Internet-Draft. 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
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or to cite them other than as "work in progress".
To learn the current status of any Internet-Draft, please check the
"1id-abstracts.txt" listing contained in the Internet-Drafts Shadow
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munnari.oz.au (Pacific Rim), ftp.ietf.org (US East Coast), or
ftp.isi.edu (US West Coast).
Copyright Notice
Copyright (C)The Internet Society (1998). All Rights Reserved.
Abstract
This document is one of a set of documents, which together describe all
aspects of a new Internet Printing Protocol (IPP). IPP is an application
level protocol that can be used for distributed printing using Internet
tools and technologies. The protocol is heavily influenced by the
printing model introduced in the Document Printing Application (DPA)
[ISO10175] standard. Although DPA specifies both end user and
administrative features, IPP version 1.0 (IPP/1.0) focuses only on end
user functionality.
The full set of IPP documents includes:
Design Goals for an Internet Printing Protocol [ipp-req]
(informational)
Rationale for the Structure and Model and Protocol for the Internet
Printing Protocol [ipp-rat] (informational)
Internet Printing Protocol/1.0: Model and Semantics [ipp mod]
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Internet Printing Protocol/1.0: Encoding and Transport (this
document)
Mapping between LPD and IPP Protocols [ipp lpd] (informational)
The design goals document, "Design Goals for an Internet Printing
Protocol", takes a broad look at distributed printing functionality, and
it enumerates real-life scenarios that help to clarify the features that
need to be included in a printing protocol for the Internet. It
identifies requirements for three types of users: end users, operators,
and administrators. The design goals document calls out a subset of end
user requirements that are satisfied in IPP/1.0. Operator and
administrator requirements are out of scope for version 1.0. The
rationale document, "Rationale for the Structure and Model and Protocol
for the Internet Printing Protocol", describes IPP from a high level
view, defines a roadmap for the various documents that form the suite of
IPP specifications, and gives background and rationale for the IETF
working group's major decisions. The document, "Internet Printing
Protocol/1.0: Model and Semantics", describes a simplified model with
abstract objects, their attributes, and their operations. The model
introduces a Printer and a Job. The Job supports multiple documents per
Job. The model document also addresses how security,
internationalization, and directory issues are addressed. The protocol
specification, "Internet Printing Protocol/1.0: Encoding and Transport",
is a formal mapping of the abstract operations and attributes defined in
the model document onto HTTP/1.1. The protocol specification defines the
encoding rules for a new Internet media type called "application/ipp".
The "Mapping between LPD and IPP Protocols" gives some advice to
implementors of gateways between IPP and LPD (Line Printer Daemon)
implementations.
This document is the "Internet Printing Protocol/1.0: Encoding and
Transport" document.
Notice
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary rights
which may cover technology that may be required to practice this
standard. Please address the information to the IETF Executive
Director.
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Table of Contents
1. Introduction........................................................4
2. Conformance Terminology.............................................4
3. Encoding of the Operation Layer....................................4
3.1 Picture of the Encoding .......................................5
3.2 Syntax of Encoding ............................................7
3.3 Version-number ................................................8
3.4 Operation-id ..................................................8
3.5 Status-code ...................................................9
3.6 Request-id ....................................................9
3.7 Tags ..........................................................9
3.7.1 Delimiter Tags ...........................................9
3.7.2 Value Tags ..............................................10
3.8 Name-Length ..................................................12
3.9 (Attribute) Name .............................................12
3.10 Value Length .................................................14
3.11 (Attribute) Value ............................................15
3.12 Data .........................................................16
4. Encoding of Transport Layer........................................16
4.1 General Headers ..............................................18
4.2 Request Headers .............................................19
4.3 Response Headers .............................................20
4.4 Entity Headers ..............................................21
5. Security Considerations............................................22
6. References.........................................................22
7. Author's Address...................................................24
8. Other Participants:................................................24
9. Appendix A: Protocol Examples......................................25
9.1 Print-Job Request ............................................25
9.2 Print-Job Response (successful) ..............................26
9.3 Print-Job Response (failure) .................................27
9.4 Print-URI Request ............................................27
9.5 Create-Job Request ...........................................28
9.6 Get-Jobs Request .............................................29
9.7 Get-Jobs Response ............................................30
10.Appendix B: Registration of MIME Media Type Information for
"application/ipp".....................................................31
11.Appendix C: Full Copyright Statement ..............................33
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1. Introduction
This document contains the rules for encoding IPP operations and
describes two layers: the transport layer and the operation layer.
The transport layer consists of an HTTP/1.1 request or response. RFC
2068 [rfc2068] describes HTTP/1.1. This document specifies the HTTP
headers that an IPP implementation supports.
The operation layer consists of a message body in an HTTP request or
response. The document "Internet Printing Protocol/1.0: Model and
Semantics" [ipp-mod] defines the semantics of such a message body and
the supported values. This document specifies the encoding of an IPP
operation. The aforementioned document [ipp-mod] is henceforth referred
to as the "IPP model document"
2. Conformance Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT",
"RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be
interpreted as described in RFC 2119 [rfc2119].
3. Encoding of the Operation Layer
The operation layer MUST contain a single operation request or operation
response. Each request or response consists of a sequence of values and
attribute groups. Attribute groups consist of a sequence of attributes
each of which is a name and value. Names and values are ultimately
sequences of octets
The encoding consists of octets as the most primitive type. There are
several types built from octets, but three important types are
integers, character strings and octet strings, on which most other
data types are built. Every character string in this encoding MUST be a
sequence of characters where the characters are associated with some
charset and some natural language. . A character string MUST be in
"reading order" with the first character in the value (according to
reading order) being the first character in the encoding. A character
string whose associated charset is US-ASCII whose associated natural
language is US English is henceforth called a US-ASCII-STRING. A
character string whose associated charset and natural language are
specified in a request or response as described in the model document is
henceforth called a LOCALIZED-STRING. An octet string MUST be in "IPP
model document order" with the first octet in the value (according to
the IPP model document order) being the first octet in the encoding
Every integer in this encoding MUST be encoded as a signed integer using
two's-complement binary encoding with big-endian format (also known as
"network order" and "most significant byte first"). The number of octets
for an integer MUST be 1, 2 or 4, depending on usage in the protocol.
Such one-octet integers, henceforth called SIGNED-BYTE, are used for the
version-number and tag fields. Such two-byte integers, henceforth called
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SIGNED-SHORT are used for the operation-id, status-code and length
fields. Four byte integers, henceforth called SIGNED-INTEGER, are used
for values fields and the sequence number.
The following two sections present the operation layer in two ways
. informally through pictures and description
. formally through Augmented Backus-Naur Form (ABNF), as specified by
RFC 2234 [rfc2234]
3.1 Picture of the Encoding
The encoding for an operation request or response consists of:
-----------------------------------------------
| version-number | 2 bytes - required
-----------------------------------------------
| operation-id (request) |
| or | 2 bytes - required
| status-code (response) |
-----------------------------------------------
| request-id | 4 bytes - required
-----------------------------------------------------------
| xxx-attributes-tag | 1 byte |
----------------------------------------------- |-0 or more
| xxx-attribute-sequence | n bytes |
-----------------------------------------------------------
| end-of-attributes-tag | 1 byte - required
-----------------------------------------------
| data | q bytes - optional
-----------------------------------------------
The xxx-attributes-tag and xxx-attribute-sequence represents four
different values of "xxx", namely, operation, job, printer and
unsupported. The xxx-attributes-tag and an xxx-attribute-sequence
represent attribute groups in the model document. The xxx-attributes-tag
identifies the attribute group and the xxx-attribute-sequence contains
the attributes.
The expected sequence of xxx-attributes-tag and xxx-attribute-sequence
is specified in the IPP model document for each operation request and
operation response.
A request or response SHOULD contain each xxx-attributes-tag defined for
that request or response even if there are no attributes except for the
unsupported-attributes-tag which SHOULD be present only if the
unsupported-attribute-sequence is non-empty. A receiver of a request
MUST be able to process as equivalent empty attribute groups:
a) an xxx-attributes-tag with an empty xxx-attribute-sequence,
b) an expected but missing xxx-attributes-tag.
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The data is omitted from some operations, but the end-of-attributes-tag
is present even when the data is omitted. Note, the xxx-attributes-tags
and end-of-attributes-tag are called `delimiter-tags'. Note: the xxx-
attribute-sequence, shown above may consist of 0 bytes, according to the
rule below.
An xxx-attributes-sequence consists of zero or more compound-attributes.
-----------------------------------------------
| compound-attribute | s bytes - 0 or more
-----------------------------------------------
A compound-attribute consists of an attribute with a single value
followed by zero or more additional values.
Note: a `compound-attribute' represents a single attribute in the model
document. The `additional value' syntax is for attributes with 2 or
more values.
Each attribute consists of:
-----------------------------------------------
| value-tag | 1 byte
-----------------------------------------------
| name-length (value is u) | 2 bytes
-----------------------------------------------
| name | u bytes
-----------------------------------------------
| value-length (value is v) | 2 bytes
-----------------------------------------------
| value | v bytes
-----------------------------------------------
An additional value consists of:
-----------------------------------------------------------
| value-tag | 1 byte |
----------------------------------------------- |
| name-length (value is 0x0000) | 2 bytes |
----------------------------------------------- |-0 or more
| value-length (value is w) | 2 bytes |
----------------------------------------------- |
| value | w bytes |
-----------------------------------------------------------
Note: an additional value is like an attribute whose name-length is 0.
From the standpoint of a parsing loop, the encoding consists of:
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-----------------------------------------------
| version-number | 2 bytes - required
-----------------------------------------------
| operation-id (request) |
| or | 2 bytes - required
| status-code (response) |
-----------------------------------------------
| request-id | 4 bytes - required
-----------------------------------------------------------
| tag (delimiter-tag or value-tag) | 1 byte |
----------------------------------------------- |-0 or more
| empty or rest of attribute | x bytes |
-----------------------------------------------------------
| end-of-attributes-tag | 2 bytes - required
-----------------------------------------------
| data | y bytes - optional
-----------------------------------------------
The value of the tag determines whether the bytes following the tag are:
. attributes
. data
. the remainder of a single attribute where the tag specifies the
type of the value.
3.2 Syntax of Encoding
The syntax below is ABNF [rfc2234] except `strings of literals' MUST be
case sensitive. For example `a' means lower case `a' and not upper case
`A'. In addition, SIGNED-BYTE and SIGNED-SHORT fields are represented
as `%x' values which show their range of values.
ipp-message = ipp-request / ipp-response
ipp-request = version-number operation-id request-id
*(xxx-attributes-tag xxx-attribute-sequence) end-of-
attributes-tag data
ipp-response = version-number status-code request-id
*(xxx-attributes-tag xxx-attribute-sequence) end-of-
attributes-tag data
xxx-attribute-sequence = *compound-attribute
xxx-attributes-tag = operation-attributes-tag / job-attributes-tag /
printer-attributes-tag / unsupported-attributes-tag
version-number = major-version-number minor-version-number
major-version-number = SIGNED-BYTE ; initially %d1
minor-version-number = SIGNED-BYTE ; initially %d0
operation-id = SIGNED-SHORT ; mapping from model defined below
status-code = SIGNED-SHORT ; mapping from model defined below
request-id = SIGNED-INTEGER ; whose value is > 0
compound-attribute = attribute *additional-values
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attribute = value-tag name-length name value-length value
additional-values = value-tag zero-name-length value-length value
name-length = SIGNED-SHORT ; number of octets of `name'
name = LALPHA *( LALPHA / DIGIT / "-" / """ / "." )
value-length = SIGNED-SHORT ; number of octets of `value'
value = OCTET-STRING
data = OCTET-STRING
zero-name-length = %x00.00 ; name-length of 0
operation-attributes-tag = %x01 ; tag of 1
job-attributes-tag = %x02 ; tag of 2
printer-attributes-tag = %x04 ; tag of 4
unsupported- attributes-tag = %x05 ; tag of 5
end-of-attributes-tag = %x03
; tag of 3
value-tag = %x10-FF
SIGNED-BYTE = BYTE
SIGNED-SHORT = 2BYTE
DIGIT = %x30-39 ; "0" to "9"
LALPHA = %x61-7A ; "a" to "z"
BYTE = %x00-FF
OCTET-STRING = *BYTE
The syntax allows an xxx-attributes-tag to be present when the xxx-
attribute-sequence that follows is empty. The syntax is defined this way
to allow for the response of Get-Jobs where no attributes are returned
for some job-objects. Although it is RECOMMENDED that the sender not
send an xxx-attributes-tag if there are no attributes (except in the
Get-Jobs response just mentioned), the receiver MUST be able to decode
such syntax.
3.3 Version-number
The version-number MUST consist of a major and minor version-number,
each of which MUST be represented by a SIGNED-BYTE. The protocol
described in this document MUST have a major version-number of 1 (0x01)
and a minor version-number of 0 (0x00). The ABNF for these two bytes
MUST be %x01.00.
3.4 Operation-id
Operation-ids are defined as enums in the model document. An operation-
ids enum value MUST be encoded as a SIGNED-SHORT
Note: the values 0x4000 to 0xFFFF are reserved for private extensions.
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3.5 Status-code
Status-codes are defined as enums in the model document. A status-code
enum value MUST be encoded as a SIGNED-SHORT
The status-code is an operation attribute in the model document. In the
protocol, the status-code is in a special position, outside of the
operation attributes.
If an IPP status-code is returned, then the HTTP Status-Code MUST be 200
(OK). With any other HTTP Status-Code value, the HTTP response MUST NOT
contain an IPP message-body, and thus no IPP status-code is returned.
3.6 Request-id
The request-id allows a client to match a response with a request. This
mechanism is unnecessary in HTTP, but may be useful when application/ipp
entity bodies are used in another context.
The request-id in a response MUST be the value of the request-id
received in the corresponding request. A client can set the request-id
in each request to a unique value or a constant value, such as 1,
depending on what the client does with the request-id returned in the
response. The value of the request-id MUST be greater than zero.
3.7 Tags
There are two kinds of tags:
. delimiter tags: delimit major sections of the protocol, namely
attributes and data
. value tags: specify the type of each attribute value
3.7.1 Delimiter Tags
The following table specifies the values for the delimiter tags:
Tag Value (Hex) Delimiter
0x00 reserved
0x01 operation-attributes-tag
0x02 job-attributes-tag
0x03 end-of-attributes-tag
0x04 printer-attributes-tag
0x05 unsupported-attributes-tag
0x06-0x0e reserved for future delimiters
0x0F reserved for future chunking-end-of-attributes-
tag
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When an xxx-attributes-tag occurs in the protocol, it MUST mean that
zero or more following attributes up to the next delimiter tag are
attributes belonging to group xxx as defined in the model document,
where xxx is operation, job, printer, unsupported.
Doing substitution for xxx in the above paragraph, this means the
following. When an operation-attributes-tag occurs in the protocol, it
MUST mean that the zero or more following attributes up to the next
delimiter tag are operation attributes as defined in the model document.
When an job-attributes-tag occurs in the protocol, it MUST mean that the
zero or more following attributes up to the next delimiter tag are job
attributes as defined in the model document. When an printer-attributes-
tag occurs in the protocol, it MUST mean that the zero or more following
attributes up to the next delimiter tag are printer attributes as
defined in the model document. When an unsupported- attributes-tag
occurs in the protocol, it MUST mean that the zero or more following
attributes up to the next delimiter tag are unsupported attributes as
defined in the model document.
The operation-attributes-tag and end-of-attributes-tag MUST each occur
exactly once in an operation. The operation-attributes-tag MUST be the
first tag delimiter, and the end-of-attributes-tag MUST be the last tag
delimiter. If the operation has a document-content group, the document
data in that group MUST follow the end-of-attributes-tag
Each of the other three xxx-attributes-tags defined above is OPTIONAL
in an operation and each MUST occur at most once in an operation, except
for job-attributes-tag in a Get-Jobs response which may occur zero or
more times.
The order and presence of delimiter tags for each operation request and
each operation response MUST be that defined in the model document. For
further details, see section 3.9 "(Attribute) Name" and .section 9
"Appendix A: Protocol Examples"
A Printer MUST treat the reserved delimiter tags differently from
reserved value tags so that the Printer knows that there is an entire
attribute group that it doesn't understand as opposed to a single value
that it doesn't understand.
3.7.2 Value Tags
The remaining tables show values for the value-tag, which is the first
octet of an attribute. The value-tag specifies the type of the value of
the attribute. The following table specifies the "out-of-band" values
for the value-tag.
Tag Value (Hex) Meaning
0x10 unsupported
0x11 reserved for future `default'
0x12 unknown
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Tag Value (Hex) Meaning
0x13 no-value
0x14-0x1F reserved for future "out-of-band" values.
The "unsupported" value MUST be used in the attribute-sequence of an
error response for those attributes which the printer does not support.
The "default" value is reserved for future use of setting value back to
their default value. The "unknown" value is used for the value of a
supported attribute when its value is temporarily unknown. . The "no-
value" value is used for a supported attribute to which no value has
been assigned, e.g. "job-k-octets-supported" has no value if an
implementation supports this attribute, but an administrator has not
configured the printer to have a limit.
The following table specifies the integer values for the value-tag
Tag Value (Hex) Meaning
0x20 reserved
0x21 integer
0x22 boolean
0x23 enum
0x24-0x2F reserved for future integer types
NOTE: 0x20 is reserved for "generic integer" if should ever be needed.
The following table specifies the octetString values for the value-tag
Tag Value (Hex) Meaning
0x30 octetString with an unspecified format
0x31 dateTime
0x32 resolution
0x33 rangeOfInteger
0x34 reserved for collection (in the future)
0x35 textWithLanguage
0x36 nameWithLanguage
0x37-0x3F reserved for future octetString types
The following table specifies the character-string values for the value-
tag
Tag Value (Hex) Meaning
0x40 reserved
0x41 textWithoutLanguage
0x42 nameWithoutLanguage
0x43 reserved
0x44 keyword
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Tag Value (Hex) Meaning
0x45 uri
0x46 uriScheme
0x47 charset
0x48 naturalLanguage
0x49 mimeMediaType
0x4A-0x5F reserved for future character string types
NOTE: 0x40 is reserved for "generic character-string" if should ever be
needed.
NOTE: an attribute value always has a type, which is explicitly
specified by its tag; one such tag value is "nameWithoutLanguage". An
attribute's name has an implicit type, which is keyword.
The values 0x60-0xFF are reserved for future types. There are no values
allocated for private extensions. A new type MUST be registered via the
type 2 process.
The tag 0x7F is reserved for extending types beyond the 255 values
available with a single byte. A tag value of 0x7F MUST signify that the
first 4 bytes of the value field are interpreted as the tag value.
Note, this future extension doesn't affect parsers that are unaware of
this special tag. The tag is like any other unknown tag, and the value
length specifies the length of a value which contains a value that the
parser treats atomically. All these 4 byte tag values are currently
unallocated except that the values 0x40000000-0x7FFFFFFF are reserved
for experimental use.
3.8 Name-Length
The name-length field MUST consist of a SIGNED-SHORT. This field MUST
specify the number of octets in the name field which follows the name-
length field, excluding the two bytes of the name-length field.
If a name-length field has a value of zero, the following name field
MUST be empty, and the following value MUST be treated as an additional
value for the preceding attribute. Within an attribute-sequence, if two
attributes have the same name, the first occurrence MUST be ignored. The
zero-length name is the only mechanism for multi-valued attributes.
3.9 (Attribute) Name
Some operation elements are called parameters in the model document
[ipp-mod]. They MUST be encoded in a special position and they MUST NOT
appear as an operation attributes. These parameters are:
. "version-number": The parameter named "version-number" in the IPP
model document MUST become the "version-number" field in the
operation layer request or response.
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. "operation-id": The parameter named "operation-id" in the IPP model
document MUST become the "operation-id" field in the operation
layer request.
. "status-code": The parameter named "status-code" in the IPP model
document MUST become the "status-code" field in the operation layer
response.
. "request-id": The parameter named "request-id" in the IPP model
document MUST become the "request-id" field in the operation layer
request or response.
All Printer and Job objects are identified by a Uniform Resource
Identifier (URI) [rfc1630] so that they can be persistently and
unambiguously referenced. The notion of a URI is a useful concept,
however, until the notion of URI is more stable (i.e., defined more
completely and deployed more widely), it is expected that the URIs used
for IPP objects will actually be URLs [rfc1738] [rfc1808]. Since every
URL is a specialized form of a URI, even though the more generic term
URI is used throughout the rest of this document, its usage is intended
to cover the more specific notion of URL as well.
Some operation elements are encoded twice, once as the request-URI on
the HTTP Request-Line and a second time as a REQUIRED operation
attribute in the application/ipp entity. These attributes are the
target URI for the operation:
. "printer-uri": When the target is a printer and the transport is
HTTP or HTTPS (for TLS), the target printer-uri defined in each
operation in the IPP model document MUST be an operation attribute
called "printer-uri" and it MUST also be specified outside of the
operation layer as the request-URI on the Request-Line at the HTTP
level.
. "job-uri": When the target is a job and the transport is HTTP or
HTTPS (for TLS), the target job-uri of each operation in the IPP
model document MUST be an operation attribute called "job-uri" and
it MUST also be specified outside of the operation layer as the
request-URI on the Request-Line at the HTTP level.
Note: Because the target URI is included twice in an operation, the
potential exists that these two values reference the same IPP object,
but are not literally identical. One can be a relative URI and the other
can be an absolute URI. HTTP/1.1 allows clients to generate and send a
relative URI rather than an absolute URI. A relative URI identifies a
resource with the scope of the HTTP server, but does not include scheme,
host or port. The following statements characterize how URLs should be
used in the mapping of IPP onto HTTP/1.1:
1. Although potentially redundant, a client MUST supply the target of
the operation both as an Operation and as a URI at the HTTP layer.
The rationale for this decision is to maintain a consistent set of
rules for mapping IPP to possibly many communication layers, even
where URLs are not used as the addressing mechanism.
2. Even though these two URLs might not be literally identical (one
being relative and the other being absolute), they MUST both
reference the same IPP object.
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3. The URI in the HTTP layer is either relative or absolute and is
used by the HTTP server to route the HTTP request to the correct
resource relative to that HTTP server. The HTTP server need not be
aware of the URI within the operation request.
4. Once the HTTP server resource begins to process the HTTP request,
it might get the reference to the appropriate IPP Printer object
from either the HTTP URI (using to the context of the HTTP server
for relative URLs) or from the URI within the operation request;
the choice is up to the implementation.
5. HTTP URIs can be relative or absolute, but the target URI in the
operation MUST be an absolute URI
The model document arranges the remaining attributes into groups for
each operation request and response. Each such group MUST be represented
in the protocol by an xxx-attribute-sequence preceded by the appropriate
xxx-attributes-tag (See the table below and section 9 "Appendix A:
Protocol Examples"). In addition, the order of these xxx-attributes-tags
and xxx-attribute-sequences in the protocol MUST be the same as in the
model document, but the order of attributes within each xxx-attribute-
sequence MUST be unspecified. The table below maps the model document
group name to xxx-attributes-sequence
Model Document Group xxx-attributes-sequence
Operation Attributes operations-attributes-sequence
Job Template Attributes job-attributes-sequence
Job Object Attributes job-attributes-sequence
Unsupported Attributes unsupported- attributes-sequence
Requested Attributes (Get- job-attributes-sequence
Job-Attributes)
Requested Attributes (Get- printer-attributes-sequence
Printer-Attributes)
Document Content in a special position as described above
If an operation contains attributes from more than one job object (e.g.
Get-Jobs response), the attributes from each job object MUST be in a
separate job-attribute-sequence, such that the attributes from the ith
job object are in the ith job-attribute-sequence. See Section 9
"Appendix A: Protocol Examples" for table showing the application of the
rules above.
3.10 Value Length
Each attribute value MUST be preceded by a SIGNED-SHORT which MUST
specify the number of octets in the value which follows this length,
exclusive of the two bytes specifying the length.
For any of the types represented by binary signed integers, the sender
MUST encode the value in exactly four octets..
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For any of the types represented by character-strings, the sender MUST
encode the value with all the characters of the string and without any
padding characters.
If a value-tag contains an "out-of-band" value, such as "unsupported",
the value-length MUST be 0 and the value empty " the value has no
meaning when the value-tag has an "out-of-band" value. If a client
receives a response with a nonzero value-length in this case, it MUST
ignore the value field. If a printer receives a request with a nonzero
value-length in this case, it MUST reject the request.
3.11 (Attribute) Value
The syntax types and most of the details of their representation are
defined in the IPP model document. The table below augments the
information in the model document, and defines the syntax types from the
model document in terms of the 5 basic types defined in section 3
"Encoding of the Operation Layer". The 5 types are US-ASCII-STRING,
LOCALIZED-STRING, SIGNED-INTEGER, SIGNED-SHORT, SIGNED-BYTE, and OCTET-
STRING.
Syntax of Attribute Encoding
Value
textWithoutLanguage, LOCALIZED-STRING.
nameWithoutLanguage
textWithLanguage OCTET"STRING consisting of 4 fields:
a) a SIGNED-SHORT which is the number of octets in the following field
b) a value of type natural-language,
c) a SIGNED-SHORT which is the number of octets
in the following field,
d) a value of type textWithoutLanguage.
The length of a textWithLanguage value MUST be 4
+ the value of field a + the value of field c.
nameWithLanguage OCTET"STRING consisting of 4 fields:
a) a SIGNED-SHORT which is the number of octets
in the following field
b) a value of type natural-language,
c) a SIGNED-SHORT which is the number of octets
in the following field
d) a value of type nameWithoutLanguage.
The length of a nameWithLanguage value MUST be 4
+ the value of field a + the value of field c.
charset, US-ASCII-STRING
naturalLanguage,
mimeMediaType,
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Syntax of Attribute Encoding
Value
keyword, uri, and
uriScheme
boolean SIGNED-BYTE where 0x00 is `false' and 0x01 is
`true'
integer and enum a SIGNED-INTEGER
dateTime OCTET-STRING consisting of eleven octets whose
contents are defined by "DateAndTime" in RFC
1903 [rfc1903].
resolution OCTET"STRING consisting of nine octets of 2
SIGNED-INTEGERs followed by a SIGNED-BYTE. The
first SIGNED-INTEGER contains the value of cross
feed direction resolution . The second SIGNED-
INTEGER contains the value of feed direction
resolution. The SIGNED-BYTE contains the units
value.
rangeOfInteger Eight octets consisting of 2 SIGNED-INTEGERs.
The first SIGNED-INTEGERs contains the lower
bound and the second SIGNED-INTEGERs contains
the upper bound.
1setOf X encoding according to the rules for an attribute
with more than 1 value. Each value X is encoded
according to the rules for encoding its type.
octetString OCTET-STRING
The type of the value in the model document determines the encoding in
the value and the value of the value-tag.
3.12 Data
The data part MUST include any data required by the operation
4. Encoding of Transport Layer
HTTP/1.1 is the transport layer for this protocol.
The operation layer has been designed with the assumption that the
transport layer contains the following information:
. the URI of the target job or printer operation
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. the total length of the data in the operation layer, either as a
single length or as a sequence of chunks each with a length.
It is REQUIRED that a printer implementation support HTTP over the IANA
assigned Well Known Port 631 (the IPP default port), though a printer
implementation may support HTTP over port some other port as well. In
addition, a printer may have to support another port for privacy (See
Section 5 "Security Considerations".
Note: even though port 631 is the IPP default, port 80 remains the
default for an HTTP URI. Thus a URI for a printer using port 631 MUST
contain an explicit port, e.g. "http://forest:631/pinetree".
Note: Consistent with RFC 2068 (HTTP/1.1), HTTP URI's for IPP implicitly
reference port 80. If a URI references some other port, the port number
MUST be explicitly specified in the URI.
Each HTTP operation MUST use the POST method where the request-URI is
the object target of the operation, and where the "Content-Type" of the
message-body in each request and response MUST be "application/ipp". The
message-body MUST contain the operation layer and MUST have the syntax
described in section 3.2 "Syntax of Encoding". A client implementation
MUST adhere to the rules for a client described in RFC 2068 [rfc2068]. A
printer (server) implementation MUST adhere the rules for an origin
server described in RFC 2068.
The IPP layer doesn't have to deal with chunking. In the context of CGI
scripts, the HTTP layer removes any chunking information in the received
data.
A client MUST NOT expect a response from an IPP server until after the
client has sent the entire response. But a client MAY listen for an
error response that an IPP server MAY send before it receives all the
data. In this case a client, if chunking the data, can send a premature
zero-length chunk to end the request before sending all the data. If the
request is blocked for some reason, a client MAY determine the reason by
opening another connection to query the server.
In the following sections, there are a tables of all HTTP headers which
describe their use in an IPP client or server. The following is an
explanation of each column in these tables.
. the "header" column contains the name of a header
. the "request/client" column indicates whether a client sends the
header.
. the "request/ server" column indicates whether a server supports
the header when received.
. the "response/ server" column indicates whether a server sends the
header.
. the "response /client" column indicates whether a client supports
the header when received.
. the "values and conditions" column specifies the allowed header
values and the conditions for the header to be present in a
request/response.
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The table for "request headers" does not have columns for responses, and
the table for "response headers" does not have columns for requests.
The following is an explanation of the values in the "request/client"
and "response/ server" columns.
. must: the client or server MUST send the header,
. must-if: the client or server MUST send the header when the
condition described in the "values and conditions" column is met,
. may: the client or server MAY send the header
. not: the client or server SHOULD NOT send the header. It is not
relevant to an IPP implementation.
The following is an explanation of the values in the "response/client"
and "request/ server" columns.
. must: the client or server MUST support the header,
. may: the client or server MAY support the header
. not: the client or server SHOULD NOT support the header. It is not
relevant to an IPP implementation.
4.1 General Headers
The following is a table for the general headers.
General- Request Response Values and Conditions
Header
Client Server Server Client
Cache- must not must not "no-cache" only
Control
Connection must-if must must- must "close" only. Both
if client and server
SHOULD keep a
connection for the
duration of a sequence
of operations. The
client and server MUST
include this header
for the last operation
in such a sequence.
Date may may must may per RFC 1123 [rfc1123]
from RFC 2068
Pragma must not must not "no-cache" only
Transfer- must-if must must- must "chunked" only .
Encoding if Header MUST be present
if Content-Length is
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General- Request Response Values and Conditions
Header
Client Server Server Client
absent.
Upgrade not not not not
Via not not not not
4.2 Request Headers
The following is a table for the request headers.
Request-Header Client Server Request Values and Conditions
Accept may must "application/ipp" only. This
value is the default if the
client omits it
Accept-Charset not not Charset information is within
the application/ipp entity
Accept-Encoding may must empty and per RFC 2068 [rfc2068]
and IANA registry for content-
codings
Accept-Language not not language information is within
the application/ipp entity
Authorization must-if must per RFC 2068. A client MUST send
this header when it receives a
401 "Unauthorized" response and
does not receive a "Proxy-
Authenticate" header.
From not not per RFC 2068. Because RFC
recommends sending this header
only with the user's approval, it
is not very useful
Host must must per RFC 2068
If-Match not not
If-Modified- not not
Since
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Request-Header Client Server Request Values and Conditions
If-None-Match not not
If-Range not not
If-Unmodified- not not
Since
Max-Forwards not not
Proxy- must-if not per RFC 2068. A client MUST send
Authorization this header when it receives a
401 "Unauthorized" response and a
"Proxy-Authenticate" header.
Range not not
Referer not not
User-Agent not not
4.3 Response Headers
The following is a table for the request headers.
Response- Server Client Response Values and Conditions
Header
Accept-Ranges not not
Age not not
Location must-if may per RFC 2068. When URI needs
redirection.
Proxy- not must per RFC 2068
Authenticate
Public may may per RFC 2068
Retry-After may may per RFC 2068
Server not not
Vary not not
Warning may may per RFC 2068
WWW- must-if must per RFC 2068. When a server needs to
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Response- Server Client Response Values and Conditions
Header
Authenticate authenticate a client.
4.4 Entity Headers
The following is a table for the entity headers.
Entity-Header Request Response Values and Conditions
Client Server Server Client
Allow not not not not
Content-Base not not not not
Content- may must must must per RFC 2068 and IANA
Encoding registry for content
codings.
Content- not not not not Application/ipp
Language handles language
Content- must-if must must-if must the length of the
Length message-body per RFC
2068. Header MUST be
present if Transfer-
Encoding is absent..
Content- not not not not
Location
Content-MD5 may may may may per RFC 2068
Content-Range not not not not
Content-Type must must must must "application/ipp"
only
ETag not not not not
Expires not not not not
Last-Modified not not not not
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5. Security Considerations
The IPP Model document defines an IPP implementation with "privacy" as
one that implements Transport Layer Security (TLS) Version 1.0. TLS
meets the requirements for IPP security with regards to features such as
mutual authentication and privacy (via encryption). The IPP Model
document also outlines IPP-specific security considerations and should
be the primary reference for security implications with regards to the
IPP protocol itself.
The IPP Model document defines an IPP implementation with
"authentication" as one that implements the standard way for
transporting IPP messages within HTTP 1.1. , These include the security
considerations outlined in the HTTP 1.1 standard document [rfc2068] and
Digest Authentication extension [rfc2069]..
The current HTTP infrastructure supports HTTP over TCP port 80. IPP
server implementations MUST offer IPP services using HTTP over the IANA
assigned Well Known Port 631 (the IPP default port). IPP server
implementations may support other ports, in addition to this port..
See further discussion of IPP security concepts in the model document
6. References
[rfc822] Crocker, D., "Standard for the Format of ARPA
Internet Text Messages", RFC 822, August 1982.
[rfc1123] Braden, S., "Requirements for Internet Hosts -
Application and Support", RFC 1123, October, 1989,
[rfc1179] McLaughlin, L. III, (editor), "Line Printer Daemon
Protocol" RFC 1179, August 1990.
[rfc1630] T. Berners-Lee, "Universal Resource Identifiers in WWW:
A Unifying Syntax for the Expression of Names and Addresses of
Objects on the Network as used in the Word-Wide Web", RFC 1630,
June 1994.
[rfc1759] Smith, R., Wright, F., Hastings, T., Zilles, S., and
Gyllenskog, J., "Printer MIB", RFC 1759, March 1995.
[rfc1738] Berners-Lee, T., Masinter, L., McCahill, M. , "Uniform
Resource Locators (URL)", RFC 1738, December, 1994.
[rfc1543] Postel, J., "Instructions to RFC Authors", RFC 1543,
October 1993.
[rfc1766] H. Alvestrand, " Tags for the Identification of
Languages", RFC 1766, March 1995.
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[rfc1808] R. Fielding, "Relative Uniform Resource Locators",
RFC1808, June 1995 [rfc1903} J. Case, et al. "Textual
Conventions for Version 2 of the Simple Network Management
Protocol (SNMPv2)", RFC 1903, January 1996.
[rfc2046] N. Freed & N. Borenstein, Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types. November 1996.
(Obsoletes RFC1521, RFC1522, RFC1590), RFC 2046.
[rfc2048] N. Freed, J. Klensin & J. Postel. Multipurpose Internet
Mail Extension (MIME) Part Four: Registration Procedures.
November 1996. (Format: TXT=45033 bytes) (Obsoletes RFC1521,
RFC1522, RFC1590) (Also BCP0013), RFC 2048.
[rfc2068] R Fielding, et al, "Hypertext Transfer Protocol "
HTTP/1.1" RFC 2068, January 1997
[rfc2069] J. Franks, et al, "An Extension to HTTP: Digest Access
Authentication" RFC 2069, January 1997
[rfc2119] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119 , March 1997
[rfc2184] N. Freed, K. Moore, "MIME Parameter Value and Encoded
Word Extensions: Character Sets, Languages, and Continuations",
RFC 2184, August 1997,
[rfc2234] D. Crocker et al., "Augmented BNF for Syntax
Specifications: ABNF", RFC 2234. November 1997.
[char] N. Freed, J. Postel: IANA Charset Registration Procedures, Work
in Progress (draft-freed-charset-reg-02.txt).
[dpa] ISO/IEC 10175 Document Printing Application (DPA), June 1996.
[iana] IANA Registry of Coded Character Sets: ftp://ftp.isi.edu/in-
notes/iana/assignments/character-sets
[ipp-lpd] Herriot, R., Hastings, T., Jacobs, N., Martin, J.,
"Mapping between LPD and IPP Protocols", draft-ietf-ipp-lpd-ipp-
map-04.txt, June 1998.
[ipp-mod] Isaacson, S., deBry, R., Hastings, T., Herriot, R.,
Powell, P., "Internet Printing Protocol/1.0: Model and
Semantics" draft-ietf-ipp-mod-10.txt, June, 1998.
[ipp-pro] Herriot, R., Butler, S., Moore, P., Tuner, R., "Internet
Printing Protocol/1.0: Encoding and Transport", draft-ietf-ipp-
pro-06.txt, June, 1998.
[ipp-rat] Zilles, S., "Rationale for the Structure and Model and
Protocol for the Internet Printing Protocol", draft-ietf-ipp-
rat-03.txt, June, 1998.
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[ipp-req] Wright, D., "Design Goals for an Internet Printing
Protocol", draft-ietf-ipp-req-02.txt, June, 1998.
7. Author's Address
Robert Herriot (editor) Paul Moore
Sun Microsystems Inc. Microsoft
901 San Antonio Road, MPK-17 One Microsoft Way
Palo Alto, CA 94303 Redmond, WA 98053
Phone: 650-786-8995 Phone: 425-936-0908
Fax: 650-786-7077 Fax: 425-93MS-FAX
Email: robert.herriot@eng.sun.com Email: paulmo@microsoft.com
Sylvan Butler Randy Turner
Hewlett-Packard Sharp Laboratories
11311 Chinden Blvd. 5750 NW Pacific Rim Blvd
Boise, ID 83714 Camas, WA 98607
Phone: 208-396-6000 Phone: 360-817-8456
Fax: 208-396-3457 Fax: : 360-817-8436
Email: sbutler@boi.hp.com Email: rturner@sharplabs.com
IPP Mailing List: ipp@pwg.org
IPP Mailing List Subscription: ipp-request@pwg.org
IPP Web Page: http://www.pwg.org/ipp/
8. Other Participants:
Chuck Adams - Tektronix Harry Lewis - IBM
Ron Bergman - Dataproducts Tony Liao - Vivid Image
Keith Carter - IBM David Manchala - Xerox
Angelo Caruso - Xerox Carl-Uno Manros - Xerox
Jeff Copeland - QMS Jay Martin - Underscore
Roger Debry - IBM Larry Masinter - Xerox
Lee Farrell - Canon Ira McDonald, Xerox
Sue Gleeson - Digital Bob Pentecost - Hewlett-Packard
Charles Gordon - Osicom Patrick Powell - SDSU
Brian Grimshaw - Apple Jeff Rackowitz - Intermec
Jerry Hadsell - IBM Xavier Riley - Xerox
Richard Hart - Digital Gary Roberts - Ricoh
Tom Hastings - Xerox Stuart Rowley - Kyocera
Stephen Holmstead Richard Schneider - Epson
Zhi-Hong Huang - Zenographics Shigern Ueda - Canon
Scott Isaacson - Novell Bob Von Andel - Allegro Software
Rich Lomicka - Digital William Wagner - Digital Products
David Kellerman - Northlake Jasper Wong - Xionics
Software
Robert Kline - TrueSpectra Don Wright - Lexmark
Dave Kuntz - Hewlett-Packard Rick Yardumian - Xerox
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Takami Kurono - Brother Lloyd Young - Lexmark
Rich Landau - Digital Peter Zehler - Xerox
Greg LeClair - Epson Frank Zhao - Panasonic
Steve Zilles - Adobe
9. Appendix A: Protocol Examples
9.1 Print-Job Request
The following is an example of a Print-Job request with job-name,
copies, and sides specified.
Octets Symbolic Value Protocol field
0x0100 1.0 version-number
0x0002 Print-Job operation-id
0x00000001 1 request-id
0x01 start operation-attributes operation-attributes-tag
0x47 charset type value-tag
0x0012 name-length
attributes- attributes-charset name
charset
0x0008 value-length
us-ascii US-ASCII value
0x48 natural-language type value-tag
0x001B name-length
attributes- attributes-natural-language name
natural-
language
0x0005 value-length
en-us en-US value
0x45 uri type value-tag
0x000B name-length
printer-uri printer-uri name
0x001A value-length
http://forest: printer pinetree value
631/pinetree
0x42 nameWithoutLanguage type value-tag
0x0008 name-length
job-name job-name name
0x0006 value-length
foobar foobar value
0x02 start job-attributes job-attributes-tag
0x21 integer type value-tag
0x0005 name-length
copies copies name
0x0004 value-length
0x00000014 20 value
0x44 keyword type value-tag
0x0005 name-length
sides sides name
0x0013 value-length
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Octets Symbolic Value Protocol field
two-sided- two-sided-long-edge value
long-edge
0x03 end-of-attributes end-of-attributes-tag
%!PS... <PostScript> data
9.2 Print-Job Response (successful)
Here is an example of a Print-Job response which is successful:
Octets Symbolic Value Protocol field
0x0100 1.0 version-number
0x0000 OK (successful) status-code
0x00000001 1 request-id
0x01 start operation-attributes operation-attributes-tag
0x47 charset type value-tag
0x0012 name-length
attributes- attributes-charset name
charset
0x0008 value-length
us-ascii US-ASCII value
0x48 natural-language type value-tag
0x001B name-length
attributes- attributes-natural- name
natural-language language
0x0005 value-length
en-us en-US value
0x41 textWithoutLanguage type value-tag
0x000E name-length
status-message status-message name
0x0002 value-length
OK OK value
0x02 start job-attributes job-attributes-tag
0x21 integer value-tag
0x0007 name-length
job-id job-id name
0x0004 value-length
147 147 value
0x45 uri type value-tag
0x0008 name-length
job-uri job-uri name
0x001E value-length
http://forest:63 job 123 on pinetree value
1/pinetree/123
0x25 nameWithoutLanguage type value-tag
0x0008 name-length
job-state job-state name
0x0001 value-length
0x03 pending value
0x03 end-of-attributes end-of-attributes-tag
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9.3 Print-Job Response (failure)
Here is an example of a Print-Job response which fails because the
printer does not support sides and because the value 20 for copies is
not supported:
Octets Symbolic Value Protocol field
0x0100 1.0 version-number
0x0400 client-error-bad-request status-code
0x00000001 1 request-id
0x01 start operation-attributes operation-attribute tag
0x47 charset type value-tag
0x0012 name-length
attributes- attributes-charset name
charset
0x0008 value-length
us-ascii US-ASCII value
0x48 natural-language type value-tag
0x001B name-length
attributes- attributes-natural-language name
natural-
language
0x0005 value-length
en-us en-US value
0x41 textWithoutLanguage type value-tag
0x000E name-length
status- status-message name
message
0x000D value-length
bad-request bad-request value
0x04 start unsupported-attributes unsupported-attributes tag
0x21 integer type value-tag
0x000C name-length
job-k-octets job-k-octets name
0x0004 value-length
0x001000000 16777216 value
0x21 integer type value-tag
0x0005 name-length
copies copies name
0x0004 value-length
0x00000014 20 value
0x10 unsupported (type) value-tag
0x0005 name-length
sides sides name
0x0000 value-length
0x03 end-of-attributes end-of-attributes-tag
9.4 Print-URI Request
The following is an example of Print-URI request with copies and job-
name parameters.
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Octets Symbolic Value Protocol field
0x0100 1.0 version-number
0x0003 Print-URI operation-id
0x00000001 1 request-id
0x01 start operation-attributes operation-attributes-tag
0x47 charset type value-tag
0x0012 name-length
attributes- attributes-charset name
charset
0x0008 value-length
us-ascii US-ASCII value
0x48 natural-language type value-tag
0x001B name-length
attributes- attributes-natural-language name
natural-
language
0x0005 value-length
en-us en-US value
0x45 uri type value-tag
0x000B name-length
printer-uri printer-uri name
0x001A value-length
http://forest printer pinetree value
:631/pinetree
0x45 uri type value-tag
0x000A name-length
document-uri document-uri name
0x11 value-length
ftp://foo.com ftp://foo.com/foo value
/foo
0x42 nameWithoutLanguage type value-tag
0x0008 name-length
job-name job-name name
0x0006 value-length
foobar foobar value
0x02 start job-attributes job-attributes-tag
0x21 integer type value-tag
0x0005 name-length
copies copies name
0x0004 value-length
0x00000001 1 value
0x03 end-of-attributes end-of-attributes-tag
9.5 Create-Job Request
The following is an example of Create-Job request with no parameters and
no attributes
Octets Symbolic Value Protocol field
0x0100 1.0 version-number
0x0005 Create-Job operation-id
0x00000001 1 request-id
0x01 start operation-attributes operation-attributes-tag
0x47 charset type value-tag
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Octets Symbolic Value Protocol field
0x0012 name-length
attributes- attributes-charset name
charset
0x0008 value-length
us-ascii US-ASCII value
0x48 natural-language type value-tag
0x001B name-length
attributes- attributes-natural-language name
natural-
language
0x0005 value-length
en-us en-US value
0x45 uri type value-tag
0x000B name-length
printer-uri printer-uri name
0x001A value-length
http://forest: printer pinetree value
631/pinetree
0x03 end-of-attributes end-of-attributes-tag
9.6 Get-Jobs Request
The following is an example of Get-Jobs request with parameters but no
attributes.
Octets Symbolic Value Protocol field
0x0100 1.0 version-number
0x000A Get-Jobs operation-id
0x00000123 0x123 request-id
0x01 start operation-attributes operation-attributes-tag
0x47 charset type value-tag
0x0012 name-length
attributes- attributes-charset name
charset
0x0008 value-length
us-ascii US-ASCII value
0x48 natural-language type value-tag
0x001B name-length
attributes- attributes-natural-language name
natural-
language
0x0005 value-length
en-us en-US value
0x45 uri type value-tag
0x000B name-length
printer-uri printer-uri name
0x001A value-length
http://forest:6 printer pinetree value
31/pinetree
0x21 integer type value-tag
0x0005 name-length
limit limit name
0x0004 value-length
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Octets Symbolic Value Protocol field
0x00000032 50 value
0x44 keyword type value-tag
0x0014 name-length
requested- requested-attributes name
attributes
0x0006 value-length
job-id job-id value
0x44 keyword type value-tag
0x0000 additional value name-length
0x0008 value-length
job-name job-name value
0x44 keyword type value-tag
0x0000 additional value name-length
0x000F value-length
document-format document-format value
0x03 end-of-attributes end-of-attributes-tag
9.7 Get-Jobs Response
The following is an of Get-Jobs response from previous request with 3
jobs. The Printer returns no information about the second job.
Octets Symbolic Value Protocol field
0x0100 1.0 version-number
0x0000 OK (successful) status-code
0x00000123 0x123 request-id (echoed
back)
0x01 start operation-attributes operation-attribute-tag
0x47 charset type value-tag
0x0012 name-length
attributes- attributes-charset name
charset
0x0008 value-length
ISO-8859-1 ISO-8859-1 value
0x48 natural-language type value-tag
0x001B name-length
attributes- attributes-natural-language name
natural-
language
0x0005 value-length
en-us en-US value
0x41 textWithoutLanguage type value-tag
0x000E name-length
status-message status-message name
0x0002 value-length
OK OK value
0x02 start job-attributes (1st job-attributes-tag
object)
0x48 natural-language type value-tag
0x001B name-length
attributes- attributes-natural-language name
natural-
language
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Octets Symbolic Value Protocol field
0x0005 value-length
fr-CA fr-CA value
0x21 integer type value-tag
0x0006 name-length
job-id job-id name
0x0004 value-length
147 147 value
0x42 nameWithoutLanguage type value-tag
0x0008 name-length
job-name job-name name
0x0003 name-length
fou fou name
0x02 start job-attributes (2nd job-attributes-tag
object)
0x02 start job-attributes (3rd job-attributes-tag
object)
0x21 integer type value-tag
0x0006 name-length
job-id job-id name
0x0004 value-length
148 148 value
0x35 nameWithLanguage value-tag
0x0008 name-length
job-name job-name name
0x0012 value-length
0x0005 sub-value-length
de-CH de-CH value
0x0009 sub-value-length
isch guet isch guet name
0x03 end-of-attributes end-of-attributes-tag
10. Appendix B: Registration of MIME Media Type Information for
"application/ipp"
This appendix contains the information that IANA requires for
registering a MIME media type. The information following this paragraph
will be forwarded to IANA to register application/ipp whose contents are
defined in Section 3 "Encoding of the Operation Layer" in this
document.
MIME type name: application
MIME subtype name: ipp
A Content-Type of "application/ipp" indicates an Internet Printing
Protocol message body (request or response). Currently there is one
version: IPP/1.0, whose syntax is described in Section 3 "Encoding of
the Operation Layer" of [ipp-pro], and whose semantics are described in
[ipp-mod]
Required parameters: none
Optional parameters: none
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Encoding considerations:
IPP/1.0 protocol requests/responses MAY contain long lines and ALWAYS
contain binary data (for example attribute value lengths).
Security considerations:
IPP/1.0 protocol requests/responses do not introduce any security risks
not already inherent in the underlying transport protocols. Protocol
mixed-version interworking rules in [ipp-mod] as well as protocol
encoding rules in [ipp-pro] are complete and unambiguous.
Interoperability considerations:
IPP/1.0 requests (generated by clients) and responses (generated by
servers) MUST comply with all conformance requirements imposed by the
normative specifications [ipp-mod] and [ipp-pro]. Protocol encoding
rules specified in [ipp-pro] are comprehensive, so that interoperability
between conforming implementations is guaranteed (although support for
specific optional features is not ensured). Both the "charset" and
"natural-language" of all IPP/1.0 attribute values which are a
LOCALIZED-STRING are explicit within IPP protocol requests/responses
(without recourse to any external information in HTTP, SMTP, or other
message transport headers).
Published specification:
[ipp-mod] Isaacson, S., deBry, R., Hastings, T., Herriot, R.,
Powell, P., "Internet Printing Protocol/1.0: Model and
Semantics" draft-ietf-ipp-mod-10.txt, June, 1998.
[ipp-pro] Herriot, R., Butler, S., Moore, P., Tuner, R., "Internet
Printing Protocol/1.0: Encoding and Transport", draft-ietf-ipp-
pro-06.txt, June, 1998.
Applications which use this media type:
Internet Printing Protocol (IPP) print clients and print servers,
communicating using HTTP/1.1 (see [IPP-PRO]), SMTP/ESMTP, FTP, or other
transport protocol. Messages of type "application/ipp" are self-
contained and transport-independent, including "charset" and "natural-
language" context for any LOCALIZED-STRING value.
Person & email address to contact for further information:
Scott A. Isaacson
Novell, Inc.
122 E 1700 S
Provo, UT 84606
Phone: 801-861-7366
Fax: 801-861-4025
Email: sisaacson@novell.com
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or
Robert Herriot
Sun Microsystems Inc.
901 San Antonio Road, MPK-17
Palo Alto, CA 94303
Phone: 650-786-8995
Fax: 650-786-7077
Email: robert.herriot@eng.sun.com
Intended usage:
COMMON
11. Appendix C: Full Copyright Statement
Copyright (C)The Internet Society (1998). All Rights Reserved
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it or
assist in its implementation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are included
on all such copies and derivative works. However, this document itself
may not be modified in any way, such as by removing the copyright notice
or references to the Internet Society or other Internet organizations,
except as needed for the purpose of developing Internet standards in
which case the procedures for copyrights defined in the Internet
Standards process must be followed, or as required to translate it into
languages other than English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an "AS
IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK
FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT
LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT
INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR PURPOSE.
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