INTERNET-DRAFT

                                                 Robert Herriot (editor)
                                                        Sun Microsystems
                                                           Sylvan Butler
                                                         Hewlett-Packard
                                                              Paul Moore
                                                              Microsoft.
                                                            Randy Turner
                                                              Sharp Labs
                                                        October 23,
                                                        November 7, 1997

         Internet Printing Protocol/1.0: Protocol Specification
                     draft-ietf-ipp-protocol-02.txt
                     draft-ietf-ipp-protocol-03.txt
     Copyright c The Internet Society (date). All Rights Reserved.

Status of this Memo

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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 technology.  The protocol is heavily influenced
by the printing model introduced in the Document Printing Application
(ISO/IEC 10175 DPA) standard [dpa].  Although DPA specifies both end
user and administrative features, IPP version 1.0 is focused only on end
user functionality.

The full set of IPP documents includes:

  Requirements for an Internet Printing Protocol: Requirements Protocol [ipp-req]
  Internet Printing Protocol/1.0: Model and Semantics [ipp-mod]
  Internet Printing Protocol/1.0: Protocol Specification (this
     document)

The requirements document takes a broad look at distributed printing
functionality, and it enumerates real-life scenarios that help to
clarify the features that need to be included in a printing protocol for
the Internet.  It identifies requirements for three types of users: end
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users, operators, and administrators.  The requirements document calls
out a subset of end user requirements that MUST be satisfied in the
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first version of IPP.  Operator and administrator requirements are out
of scope for v1.0. The model and semantics document describes a
simplified model with abstract objects, their attributes, and their
operations. The model introduces a Printer object and a Job object.  The
Job object supports multiple documents per job. The protocol
specification is formal document which incorporates the ideas in all the
other documents into a concrete mapping using clearly defined data
representations and transport protocol mappings that real implementers
can use to develop interoperable client and printer (server) side
components.

This document is the ''Internet Printing Protocol/1.0: Protocol
Specification'' 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.

Copyright c The Internet Society (date). All Rights Reserved.

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distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are included
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The limited permissions granted above are perpetual and will not be
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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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                           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..............................................6
   3.3 Version.........................................................8
   3.4 Mapping of Operations...........................................8
   3.5 Mapping of Status-code..........................................8
   3.6 Tags.............................................................   8
      3.6.1 Delimiter Tags.............................................8
      3.6.2 Value Tags.................................................9
   3.7 Name-Lengths...................................................11
   3.8 Mapping of Attribute  Names....................................11
   3.9 Value Lengths..................................................12
   3.10 Mapping of Attribute Values...................................13 Values...................................12
   3.11 Data............................................................   15
4. Encoding of Transport Layer........................................15 Layer........................................14
   4.1 General Headers................................................16 Headers................................................15
   4.2 Request  Headers...............................................17  Headers...............................................16
   4.3 Response Headers...............................................18 Headers...............................................16
   4.4 Entity  Headers................................................18  Headers................................................17
5. Security Considerations............................................19 Considerations............................................17
6. References.........................................................20 Copyright..........................................................18
7. Author's Address...................................................21 References.........................................................19
8. Other Participants:................................................22 Author's Address...................................................20
9. Other Participants:................................................20
10. Appendix A: Protocol Examples......................................22
   9.1 Examples.....................................21
   10.1 Print-Job Request..............................................22
   9.2 Request.............................................21
   10.2 Print-Job Response (successful)................................23
   9.3 (successful)...............................22
   10.3 Print-Job Response (failure)...................................24
   9.4 (failure)..................................23
   10.4 Print-URI Request..............................................25
   9.5 Request.............................................24
   10.5 Create-Job Request.............................................26
   9.6 Request............................................25
   10.6 Get-Jobs Request...............................................26
   9.7 Request..............................................25
   10.7 Get-Jobs Response..............................................27
10. Response.............................................26
11. Appendix B: Mapping of Each Operation in the Encoding.............28
11. Encoding.............27
12. Appendix C: Hints to implementors using IPP with SSL3.............32

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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 [r2068] [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-m] [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-m] [ipp-mod] is henceforth referred
to as the "IPP model document"

2. Conformance Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and  "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [r2119]. [rfc2119].

3. Encoding of  the Operation Layer

The operation layer SHALL contain a single operation request or
operation response.

The encoding consists of octets as the most primitive type. There are
several types built from octets, but two three important  types are integers
integers,  character strings and characters, octet strings, on which most  other
data types are built. Every character string in this encoding SHALL be a member
sequence of characters where the characters are associated with some
charset and some natural language. . A character string MUST be in
"network byte order" with the UCS-2 coded first character set 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 SHALL 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 encoded using UTF-8 which uses 1 in
"network byte order" with the first octet in the value (according to 3 octets
per character.
reading order) being the first octet in the encoding Every integer in
this encoding SHALL be encoded as a signed integer using two's-complement 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 SHALL be 1, 2 or 4, depending on usage in the protocol.
Such one-octet integers, henceforth called SIGNED-BYTE, are used for the
version and tag fields. Such two-
byte two-byte integers, henceforth called
SIGNED-SHORT are used for the operation, status-code and length fields.
Four byte integers, henceforth called SIGNED-INTEGER, are used for
values fields.

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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
     draft-ietf-drums-abnf-02.txt [abnf]

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3.1 Picture of the Encoding

The encoding for an operation request or response consists of:

  -----------------------------------------------
  |                    version                  |   2 bytes  - required
  -----------------------------------------------
  |operation (request) or status-code (response)|   2 bytes  - required
  -----------------------------------------------------------
  |               xxx-attributes-tag            |   1 byte  |
  -----------------------------------------------           |-0 or more
  |             xxx-attribute-sequence          |   n bytes |
  -----------------------------------------------------------
  |                  data-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-job. The xxx-attributes-tag and xxx-attribute-sequence may
be omitted if the operation has no attributes or it may be repeated with
the same or different values of "xxx" in ways that are specific to each
operation. The data is omitted from some operations, but the data-tag is
present even when the data is omitted. Note, the xxx-attributestags xxx-attributes-tags and
data-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:

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  -----------------------------------------------
  |                   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:

  -----------------------------------------------
  |                    version                  |   2 bytes  - required
  -----------------------------------------------
  |operation (request) or status-code (response)|   2 bytes  - required
  -----------------------------------------------------------
  |        tag (delimiter-tag or value-tag)     |   1 byte  |
  -----------------------------------------------           |-0 or more
  |           empty or rest of attribute        |   x bytes |
  -----------------------------------------------------------
  |                   data-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 [abnf] except `strings of literals' SHALL be
case sensitive. For example `a' means lower case  `a' and not upper case

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`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 operation
           *(xxx-attributes-tag  xxx-attribute-sequence) data-tag data
  ipp-response = version status-code
           *(xxx-attributes-tag xxx-attribute-sequence)  data-tag  data
  xxx-attribute-sequence = *compound-attribute
       ; where "xxx" in the three rules above stands for any of the
  following
       ; values:  "operation",  "job", "printer" or "unsupported-job".

  version = major-version minor-version
  major-version = SIGNED-BYTE  ; initially %d1
  minor-version = SIGNED-BYTE  ; initially %d0

  operation = SIGNED-SHORT    ; mapping from model defined below
  status-code = SIGNED-SHORT  ; mapping from model defined below

  compound-attribute = attribute *additional-values

  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=
  operation-attributes-tag =  %x01              ; tag of 1
  job-attributes-tag    =  %x02                 ; tag of 2
  printer-attributes-tag =  %x04                ; tag of 4
  unsupported-job-attributes-tag =  %x05        ; tag of 5
  data-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-attributestag 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-attributestag xxx-attributes-tag if there are no attributes (except in the Get-

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Jobs

Get-Jobs response just mentioned), the receiver MUST be able to decode
such syntax.

3.3 Version

The version SHALL consist of a major and minor version, each of which
SHALL be represented by a SIGNED-BYTE. The protocol described in this
document SHALL have a major version of 1 (0x01) and a minor version of
0 (0x00).  The ABNF for these two bytes SHALL be %x01.00.

3.4 Mapping of Operations

Operations are defined as enums in the model document. An operations
enum value SHALL be encoded as a SIGNED-SHORT

Note: the values 0x4000 to 0xFFFF are reserved for private extensions.

3.5 Mapping of Status-code

Status-codes are defined as enums in the model document. A status-code
enum value SHALL be encoded as a SIGNED-SHORT

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 SHALL NOT
contain an IPP message-body, and thus no IPP status-code is returned.

3.6 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

3.6.1 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               data-tag
   0x04               printer-attributes-tag
   0x05               unsupported-job-attributes-tag
   0x06-0x0F          reserved for future delimiters

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When an xxx-attributes-tag occurs in the protocol, it SHALL mean that
the zero or more following attributes up to the next delimiter tag are
xxx attributes as defined in the model document, where xxx is operation,
job, printer, unsupported-job.

Doing substitution for xxx in the above paragraph, this means the
following. When an operation-attributes-tag occurs in the protocol, it
SHALL 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 SHALL 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 SHALL 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-job-
attributes-tag occurs in the protocol, it SHALL mean that the zero or
more following attributes up to the next delimiter tag are unsupported-
job attributes as defined in the model document.

The  operation-attributes-tag and data-tag SHALL each occur exactly once
in an operation. The operation-attributes-tag SHALL be the first tag
delimiter, and  the data-tag SHALL be the last tag delimiter.

Each of the  four  other three  xxx-attributes-tags defined above is OPTIONAL
in an operation and each SHALL 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 data-tag SHALL occur exactly once in an operation.

If an operation contains an operations-attribute-tag, it SHALL be the
first tag delimiter.  The data-tag SHALL be the last tag delimiter.

The order and presence of delimiter tags for each operation request and
each operation response SHALL be that defined in the model document. For
further details, see Section 3.8 Mapping of Attribute  Names and
Appendix B: Mapping of Each Operation in the Encoding.

3.6.2 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 value of If  the value-tag of an attribute SHALL either
be specifies a type value specified in the model document or an "out-of-band"
value, such as "unsupported" or "default". If  the value of value-tag
for an attribute is not "out-of-band" and differs from the compoundValue, it
represents a compound value whose type
specified by is the model document, then a printer receiving such a request
MAY reject that of the attribute or just the value.  A client receiving such a
response MAY ignore the attribute or just the value.

If  ipp-attribute-fidelity is true and a printer rejects a value, it is
the same as rejecting the attribute. If  ipp-attribute-fidelity is false
and a printer rejects a value, or it a client rejects a value, then it
is as if the attribute didn't have that value. If after rejecting
values, the attribute no longer has any values the attribute is
rejected.

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Note: the intent of the above rule is for servers to be able to
understand text and name values when they don't support the
naturalLanguage override for last member of
the compound value. The following table specifies the "out-of-band"
values for the value-
tag. value-tag.

   Tag Value (Hex)  Meaning

   0x10             unsupported
   0x11             default             reserved for future `default'
   0x12             no-value             unknown
   0x13             compoundValue
   0x14-0x1F        reserved for future "out-of-band" values.

The "unsupported" value SHALL be used in the attribute-sequence of an
error response for those attributes which the printer does not support.

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The "default" value is reserved for future use of setting value back to
their default value. The "no-value" "unknown" value is used for the "no-value" value in model, e.g. when a document-attribute is returned as a set of
values and an a
supported attribute has no specified when its value for one or more of the
documents. is temporarily unknown. . The
"compoundValue"  SHALL be used to form a single value from a collection
of values, and its value is the number of members forming the compound
value, excluding the compoundValue.  For example, a text value with a
naturalLanguage override consists of 3 "values": a compoundValue with
value 2, a naturalLanguage value and a text value.

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 dictionary (in the future)
   0x35-0x3F         reserved for future octetString types

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The following table specifies the character-string values for the value-
tag

   Tag Value (Hex)   Meaning

   0x40              reserved
   0x41              text
   0x42              name
   0x43              reserved
   0x44              keyword
   0x45              uri
   0x46              uriScheme
   0x47              charSet              charset
   0x48              naturalLanguage
   0x49              mediaType              mimeMediaType
   0x4A-0x5F         reserved for future character string types

NOTE: 0x40 is reserved for "generic character-string" if should ever be
needed.

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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.

3.7 Name-Lengths

The name-length field SHALL consist of a SIGNED-SHORT. This field SHALL
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
SHALL be empty, and the following value SHALL be treated as an
additional value for the preceding attribute. Within an attribute-
sequence, if two attributes have the same name, the first occurrence
SHALL be ignored. The zero-length name is the only mechanism for multi-
valued attributes.

3.8 Mapping of Attribute  Names

Some attributes are encoded in a special position.  These attribute are:

  .  "printer-uri": The target printer-uri of each operation in the IPP
     model document SHALL be specified outside of  the operation layer
     as the request-URI on the Request-Line at the HTTP level.
  .  "job-uri": The target job-uri of each operation in the IPP model
     document SHALL be specified outside of  the operation layer as the
     request-URI on the Request-Line at the HTTP level.
  .   "document-content": The attribute named "document-content" in the
     IPP model document SHALL become the "data" in the operation layer.

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  .  "status-code": The attribute named "status-code" in the IPP model
     document SHALL become the "status-code" field in the operation
     layer response.

The model document arranges the remaining attributes into groups for
each operation request and response. Each such group SHALL be
represented in the protocol by an xxx-attribute-sequence preceded by the
appropriate xxx-attributes-tag (See the table below and Appendix B:
Mapping of Each Operation in the Encoding). In addition, the order of
these xxx-attributes-tags and xxx-attribute-sequences in the protocol
SHALL be the same as in the model document, but the order of attributes
within each xxx-attribute-sequence SHALL 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-job-attributes-sequence
Requested Attributes (Get-     job-attributes-sequence
Attributes of job object)

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Requested Attributes (Get-     printer-attributes-sequence
Attributes of printer object)
Document Content               in a special position as described above
ISSUE: coordinate this with the model document.

If an operation contains attributes from more than one job object (e.g.
Get-Jobs response), the attributes from each job object SHALL 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 10 11
"Appendix B: Mapping of Each Operation in the Encoding" for table
showing the application of the rules above.

3.9 Value Lengths

Each attribute value SHALL be preceded by a SIGNED-SHORT which SHALL
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..

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, value which is not
compoundValue, such as "unsupported", the value-length SHALL be 0 and
the value empty " the value has no meaning when the value-tag has an
"out-of-band" value. If a printer or client receives an operation with a
nonzero value-length in this case, it SHALL ignore the value field.

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3.10 Mapping of Attribute Values

The following SHALL be syntax types and most of the mapping details of attribute values to their IPP
encoding representation are
defined in the value field. IPP model document. The table below augments the
information in the model document, and defines the syntax types are from the
model document in terms of the 5 basic types defined in section 3
Encoding of  the IPP
model document. Operation Layer. The 5 types are US-ASCII-STRING,
LOCALIZED-STRING, SIGNED-INTEGER, SIGNED-SHORT, SIGNED-BYTE, and OCTET-
STRING.

   Syntax of        Encoding
   Attribute Value

   text             an octet string whose charset and

   text, name       LOCALIZED-STRING.
                    The override natural language mechanism is
                    that specified within
                    encoded by syntactically preceding the operation request text or
                    response.
                    The attributes-charset attribute with a value of
                    type `charset' MUST be in the operations-
                    attribute sequence unless the request or response
                    contains no attributes. It specifies the charset
                    for all text and name values of attributes.
                    The attributes-natural-language attribute with a
                    value of type `naturalLanguage' MUST be in the
                    operations-attribute sequence unless the request
                    or response contains no attributes. It specifies
                    the language for all text and name values of
                    attributes unless overridden.  The language can
                    be overridden on a per-object or a per-value
                    basis.
                    The language can be overridden on a per-object
                    basis only for a job-sequence within a Get-Jobs
                    response. If the attributes-natural-language
                    attribute is present within such a context, it
                    must have a value of type `naturalLanguage' and
                    it overrides the language for all text and name
                    attributes within the job-attributes sequence
                    containing it, but not for attributes in any
                    other xxx-attribute-sequence.
                    The language can be overridden on a per-value
                    basis by syntactically preceding the text or name
                    value by two values:
                    name value by two values: first a value of type
                    compoundValue whose value is 2 and second a value
                    of type naturalLanguage whose value is the
                    language override. From a protocol syntax view,

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   Syntax of        Encoding
   Attribute Value

                    there are three separate values: the
                    compoundValue, the naturalLanguage value and the
                    text or name value appear as three separate
                    values of a single attribute, value, but from a semantic view, the
                    Printer treats them as a single value where the
                    naturalLanguage value overrides the language of
                    the immediately following text or name value in
                    the attribute.  Any  The override applies to just the
                    text or name
                    values in the same or other attributes are not
                    affected by within the override.  If an attribute
                    consists of a single compound value.  Other
                    text or name value, the
                    language value turns it into an attribute with
                    two values from a syntactic view.
                    The text is encoded in "network byte order" with

Moore and Turner         Expires April 23, 1998
   Syntax of        Encoding
   Attribute Value

                    the first character in the text (according to
                    reading order) being the first character in the
                    encoding.
   name             same as text
   charset needing an octet string of US-ASCII encoded characters
                    specified in RFC 2046 [r2046] and contained in
                    the IANA character-set Registry [iana] according
                    to the IANA procedures [char].
   naturalLanguage  an octet string of US-ASCII encoded characters
                    and override must be
                    overridden with a syntax specified by RFC 1766 [r1766]
   mediaType        an octet string of US-ASCII encoded characters
                    defined by RFC 2046 [r2046] additional compoundValues.
   charset,         US-ASCII-STRING
   naturalLanguage,
   mimeMediaType,
   keyword, uri,
   and registered
                    according to the procedures of RFC 2048 [r2048]
                    for identifying a document format.  The value MAY
                    include a charset parameter, depending on the
                    specification of the Media Type in the IANA
                    Registry [iana]. Examples:
   keyword          an octet string of US-ASCII encoded characters. .
                    Allowed values are defined in the IPP model
                    document
   uri              as specified by RFC 1630 [r1630] uriScheme        same as keyword
   boolean          one binary octet          SIGNED-BYTE  where 0x00 is `false' and 0x01 is
                    `true'
   integer          a SIGNED-INTEGER, defined previously as a signed
                    integer using two's-complement binary encoding in
                    four octets with big-endian format (also known as
                    "network order" and "most significant byte
                    first"). enum             same as integer. Allowed integer values are
                    defined in the IPP model document a SIGNED-INTEGER
   compoundValue    has the same representation as an integer, but    a SIGNED-INTEGER with a different special meaning.
                    If the value of a compoundValue is n, then the n
                    following values of the attribute form a single
                    value whose type is that of the last member of
                    the compound value.  For example, if an attribute
                    has 3 successive values: compoundValue of 2, naturalLanuage
                    naturalLanguage of `fr-CA' and name of `bete', `chien',
                    then these three "values" form a single value
                    which is a name of  `bete'  `chien' in Canadian French. French..
   dateTime         OCTET-STRING consisting of eleven octets whose
                    contents are defined by "DateAndTime" in RFC 1903 [r1903].
                    [rfc1903]. Although RFC 1903 also defines an
                    eight octet format which omits the time zone, a
                    value of this type in the IPP protocol MUST use
                    the eleven octet format. [ transfer to model].
   resolution       OCTET"STRING consisting of nine octets consisting of  2
                    SIGNED-INTEGERs followed by a SIGNED-BYTE. The values are the
                    same as those specified in RFC 1759 (Printer MIB)
                    [r1759]. The
                    first SIGNED-INTEGER contains the value of prtMarkerAddressabilityXFeedDir. cross
                    feed direction resolution . The

Moore and Turner         Expires April 23, 1998
   Syntax of        Encoding
   Attribute Value second SIGNED-INTEGER SIGNED-
                    INTEGER contains the value of
                    prtMarkerAddressabilityFeedDir. feed direction
                    resolution. The SIGNED-BYTE contains the value of
                    prtMarkerAddressabilityUnit.  Note: the latter
                    value is either 3 (tenThousandsOfInches) or 4
                    (micrometers) and the addressability is in 10,000
                    units of measure. Thus the SIGNED-INTEGERS
                    represent integral values in either dots-per-inch
                    or dots-per-centimeter.
   rangeOf  integer unts
                    value.
   rangeOfInteger   Eight octets consisting of 2 SIGNED-INTEGERs. The
                    first SIGNED-INTEGERs contains the lowest value
                    of the range lower bound
                    and the second SIGNED-INTEGERs contains the highest value of the range upper
                    bound
   1setOf  X        encoding according to the rules for an attribute
                    with more than more 1 value.  Each value X is encoded
                    according to the rules for encoding its type.
   octetString      OCTET-STRING

Moore and Turner          Expires May 7, 1998

The type of the value in the model document determines the encoding in
the value and the value of the value-tag.

3.11 Data

The data part SHALL include any data required by the operation

4. Encoding of Transport Layer

HTTP/1.1 shall be 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
  .  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 support HTTP over port 80, though a
printer may support HTTP over port 516 or some other port.  In addition,
a printer may have to support another port for secure connections.

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 shall 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 shall be "application/ipp".
The message-body shall contain the operation layer and shall have the
syntax described in section 3.2 "Syntax of Encoding". A client

Moore and Turner         Expires April 23, 1998
implementation SHALL adhere to the rules for a client described in RFC
2068 [r2068]. [rfc2068]. A printer (server) implementation SHALL adhere the rules
for an origin server described in RFC 2068.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.

The table for "request headers" does not have columns for responses, and
the table for "response headers" does not have columns for requests.

Moore and Turner          Expires May 7, 1998

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.

ISSUE: an HTTP expert should review these tables for accuracy.

General-     Request         Response        Values and Conditions
Header

             Client   Server Server  Client

Moore and Turner         Expires April 23, 1998

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 [r1123] [rfc1123]
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
                                             absent.
Upgrade      not      not    not     not
Via          not      not    not     not

Moore and Turner          Expires May 7, 1998

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 [r2068] [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

Moore and Turner         Expires April 23, 1998

Request-Header   Client    Server  Request Values and Conditions
                                   is not very useful
Host             must      must    per RFC 2068
If-Match         not       not
If-Modified-     not       not
Since
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

Moore and Turner          Expires May 7, 1998

Response-      Server  Client   Response Values and Conditions
Header

                                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
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

Moore and Turner         Expires April 23, 1998

Entity-Header  Request         Response        Values and Conditions

               Client  Server  Server   Client
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

5. Security Considerations

When utilizing HTTP 1.1 as a transport of IPP, the security
considerations outlined in RFC 2068 [r2068] [rfc2068] apply.  Specifically, IPP
servers can generate a 401 "Unauthorized" response code to request
client authentication and IPP clients should correctly respond with the
proper "Authorization" header.  Both Basic Authentication (RFC 2068) and

Moore and Turner          Expires May 7, 1998

Digest Authentication (RFC 2069) [r2069] [rfc2069] flavors of authentication
SHALL be supported.  The server chooses which type(s) of authentication
to accept.  Digest Authentication is a more secure method, and is always
preferred to Basic Authentication.

For secure communication (privacy in particular), IPP SHOULD be run
using a secure communications channel. For this purpose it is the
intention to define standardization of IPP in combination with Transport
Layer Security (TLS), currently under development in the IETF, when the
TLS specifications are agreed and on the IETF standards track.

As an intercept solution for secure communication, the Secure Socket
Layer 3.0  (SSL3) could be used, but be warned that such implementations
may not be able to interoperate with a future standardized IPP and TLS
solution.  Appendix C gives some hints to implementors wanting to use
SSL3 as intercept solution.

It is possible to combine the techniques, HTTP 1.1 client authentication
(either basic techniques, HTTP 1.1 client authentication
(either basic or digest) with a secure communications channel.  Together
the two are more secure than client authentication and they perform user
authentication.

See further discussion of IPP security concepts in the model document
[ipp-mod].

6. Copyright

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 digest) with a secure communications channel.  Together 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.

Moore and Turner          Expires April 23, May 7, 1998

the two are more secure than client authentication and they perform user
authentication.

See further discussion of IPP security concepts in the model document
[ipp-m].

6.

7. References

[822]

[rfc822]                Crocker, D., "Standard for the Format of ARPA
     Internet Text Messages", RFC 822, August 1982.

[r1123]

[rfc1123]       Braden, S., "Requirements for Internet Hosts -
     Application and Support", RFC 1123, October, 1989,

[r1179]

[rfc1179]       McLaughlin, L. III, (editor), "Line Printer Daemon
     Protocol" RFC 1179, August 1990.

[r1630]

[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.

[r1759]

[rfc1759]       Smith, R., Wright, F., Hastings, T., Zilles, S., and
     Gyllenskog, J., "Printer MIB", RFC 1759, March 1995.

[r1738]

[rfc1738]       Berners-Lee, T., Masinter, L., McCahill, M. , "Uniform
     Resource Locators (URL)", RFC 1738, December, 1994.

[r1543]

[rfc1543]       Postel, J., "Instructions to RFC Authors", RFC 1543,
       October 1993.

[r1766]

[rfc1766]       H. Alvestrand, " Tags for the Identification of
       Languages", RFC 1766, March 1995.

[r1903}

[rfc1903}       J. Case, et al. "Textual Conventions for Version 2 of
       the Simple Network Managment Management Protocol (SNMPv2)", RFC 1903,
       January 1996.

[r2046]

[rfc2046]       N. Freed & N. Borenstein, Multipurpose Internet Mail
       Extensions (MIME) Part Two: Media Types. November 1996.
       (Obsoletes RFC1521, RFC1522, RFC1590), RFC 2046.

[r2048]

[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.

[r2068]

[rfc2068]       R Fielding, et al, "Hypertext Transfer Protocol "
       HTTP/1.1" RFC 2068, January 1997

[r2069]

[rfc2069]       J. Franks, et al, "An Extension to HTTP: Digest Access
       Authentication" RFC 2069, January 1997

Moore and Turner         Expires April 23, 1998

[r2119]

[rfc2119]       S. Bradner, "Key words for use in RFCs to Indicate
       Requirement Levels", RFC 2119 , March 1997

[r2184]

[rfc2184]       N. Freed, K. Moore, "MIME Parameter Value and Encoded
       Word Extensions: Character Sets, Languages, and Continuations",
       RFC 2184, August 1997,

Moore and Turner          Expires May 7, 1998

[abnf] D. Crocker et al., "Augmented BNF for Syntax Specifications:
       ABNF", draft-ietf-drums-abnf-04.txt.

[char] N. Freed, J. Postel:  IANA CharSet 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-r]

[ipp-req]       Wright, F. D., "Requirements for an Internet Printing
       Protocol:"

[ipp-m]

[ipp-mod]       Isaacson, S, deBry, R, Hasting, Hastings, T, Herriot, R, Powell,
       P, "Internet Printing Protocol/1.0: Model and Semantics"

[ssl]  Netscape, The SSL Protocol, Version 3, (Text version 3.02)
       November 1996.

7.

8.        Author's Address

Robert Herriot (editor)             Paul Moore
Sun Microsystems Inc.               Microsoft
901 San Antonio.Road, 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/

Moore and Turner         Expires April 23, 1998

8.

9. Other Participants:

Chuck Adams - Tektronix             Harry Lewis - IBM
Ron Bergman - Data Products         Tony Liao - Vivid Image
Keith Carter - IBM                  David Manchala - Xerox
Angelo Caruso - Xerox               Carl-Uno Manros - Xerox

Moore and Turner          Expires May 7, 1998

Jeff Copeland - QMS                 Jay Martin - Underscore
Roger Debry - IBM                   Larry Masinter - Xerox
Lee Farrell - Canon                 Bob Pentecost - Hewlett-Packard                 Ira McDonald, Xerox
Sue Gleeson - Digital               Patrick Powell               Bob Pentecost - SDSU Hewlett-Packard
Charles Gordon - Osicom             Jeff Rackowitz             Patrick Powell - Intermec SDSU
Brian Grimshaw - Apple              Xavier Riley              Jeff Rackowitz - Xerox Intermec
Jerry Hadsell - IBM                 Gary Roberts                 Xavier Riley - Ricoh Xerox
Richard Hart - Digital              Stuart Rowley              Gary Roberts - Kyocera Ricoh
Tom Hastings - Xerox                Stuart Rowley - Kyocera
Stephen Holmstead                   Richard Schneider - Epson
Stephen Holmstead
Zhi-Hong Huang - Zenographics       Shigern Ueda - Canon
Zhi-Hong Huang
Scott Isaacson - Zenographics Novell             Bob Von Andel - Allegro Software
Scott Isaacson
Rich Lomicka - Novell Digital              William Wagner - Digital Products
Rich Lomicka - Digital              Jasper Wong - Xionics
David Kellerman - Northlake         Don Wright         Jasper Wong - Lexmark Xionics
Software
Robert Kline - TrueSpectra          Rick Yardumian          Don Wright - Xerox Lexmark
Dave Kuntz - Hewlett-Packard        Lloyd Young        Rick Yardumian - Lexmark Xerox
Takami Kurono - Brother             Peter Zehler             Lloyd Young - Xerox Lexmark
Rich Landau - Digital               Frank Zhao               Peter Zehler - Panasonic Xerox
Greg LeClair - Epson                Frank Zhao - Panasonic
                                    Steve Zilles - Adobe

9.

10. Appendix A: Protocol Examples

9.1

10.1 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
0x0002                PrintJob             operation
0x01                  start operation-     operation-attributes tag     operation-attributestag
                      attributes
0x47                  charset type         value-tag
0x0012                                     name-length
attributes-charset    attributes-charset   name
0x0008                                     value-length
US-ASCII              US-ASCII             value
0x48                  natural-language     value-tag
                      type
0x001B                                     name-length
attributes-natural-   attributes-natural-  name
language              language
0x0005                                     value-length
en-US                 en-US                value

Moore and Turner         Expires April 23, 1998

Octets                Symbolic Value       Protocol field
0x42                  name type            value-tag
0x0008                                     name-length
job-name              job-name             name
0x0006                                     value-length
foobar                foobar               value

Moore and Turner          Expires May 7, 1998

Octets                Symbolic Value       Protocol field

0x02                  start job-           job-attributes tag           job-attributes-tag
                      attributes
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
two-sided-long-edge   two-sided-long-edge  value
0x03                  start-data           data-tag
%!PS...               <PostScript>         data

9.2

10.2 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
0x0000           OK (successful)  status-code
0x01             start operation- operation-attributes tag operation-attributes-tag
                 attributes
0x47             charset type     value-tag
0x0012                            name-length
attributes-      attributes-      name
charset          charset
0x0008                            value-length
US-ASCII         US-ASCII         value
0x48             natural-language value-tag
                 type
0x001B                            name-length
attributes-      attributes-      name
natural-         natural-language
language
0x0005                            value-length
en-US            en-US            value
0x41             text type        value-tag
0x000E                            name-length
status-message   status-message   name
0x0002                            value-length
OK               OK               value
0x02             start job-       job-attributes tag

Moore and Turner         Expires April 23, 1998

Octets           Symbolic Value   Protocol field       job-attributes-tag
                 attributes
0x21             integer          value-tag
0x0007                            name-length
job-id           job-id           name
0x0004                            value-length

Moore and Turner          Expires May 7, 1998

Octets           Symbolic Value   Protocol field

147              147              value
0x45             uri type         value-tag
0x0008                            name-length
job-uri          job-uri          name
0x000E                            value-length
http://foo/123   http://foo/123   value
0x25             name type        value-tag
0x0008                            name-length
job-state        job-state        name
0x0001                            value-length
0x03             pending          value
0x03             start-data       data-tag

9.3

10.3 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
0x0400           client-error-bad-request status-code
0x01             start operation-         operation-attribute tag
                 attribures
                 attributes
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             text type                value-tag
0x000E                                    name-length
status-message   status-message           name
0x000D                                    value-length
bad-request      bad-request              value
0x04             start unsupported-job-   unsupported-job-
                 attributes               attributes tag

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Octets           Symbolic Value           Protocol field               attributes-tag
0x21             integer type             value-tag
0x0005                                    name-length
copies           copies                   name
0x0004                                    value-length
0x00000014       20                       value

Moore and Turner          Expires May 7, 1998

Octets           Symbolic Value           Protocol field

0x10             unsupported  (type)      value-tag
0x0005                                    name-length
sides            sides                    name
0x0000                                    value-length
0x03             start-data               data-tag

9.4

10.4 Print-URI Request

The following is an example of Print-URI request with copies and job-
name parameters.

Octets              Symbolic Value      Protocol field
0x0100              1.0                 version
0x0003              Print-URI           operation
0x01                start operation-    operation-attributes tag    operation-attributes-tag
                    attributes
0x47                charset type        value-tag
0x0012                                  name-length
attributes-charset  attributes-charset  name
0x0008                                  value-length
US-ASCII            US-ASCII            value
0x48                natural-language    value-tag
                    type
0x001B                                  name-length
attributes-natural- attributes-         name
language            natural-language
0x0005                                  value-length
en-US               en-US               value
0x45                uri type            value-tag
0x000A                                  name-length
document-uri        document-uri        name
0x11                                    value-length
ftp://foo.com/foo   ftp://foo.com/foo   value
0x42                name type           value-tag
0x0008                                  name-length
job-name            job-name            name
0x0006                                  value-length
foobar              foobar              value
0x02                start job-          job-attributes tag          job-attributes-tag
                    attributes
0x21                integer type        value-tag
0x0005                                  name-length
copies              copies              name
0x0004                                  value-length
0x00000001          1                   value
0x03                start-data          data-tag
%!PS...             <PostScript>        data

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Octets              Symbolic Value      Protocol field
%!PS...             <PostScript>        data

9.5

10.5 Create-Job Request

The following is an example of Create-Job request with no parameters and
no attributes

Octets       Symbolic Value   Protocol field
             Value
0x0100       1.0              version
0x0005       Create-Job       operation
0x01         start            operation-attributes-tag
             operation-
             attributes
0x47         charset type     value-tag
0x0012                        name-length
attributes-  attributes-      name
charset      charset
0x0008                        value-length
US-ASCII     US-ASCII         value
0x48         natural-         value-tag
             language type
0x001B                        name-length
attributes-  attributes-      name
natural-     natural-
language     language
0x0005                        value-length
en-US        en-US            value
0x03         start-data       data-tag

9.6

10.6 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
0x000A                Get-Jobs             operation
0x01                  start operation-     operation-attributes-
                      attributes           tag
0x47                  charset type         value-tag
0x0012                                     name-length
attributes-charset    attributes-charset   name
0x0008                                     value-length
US-ASCII              US-ASCII             value
0x48                  natural-language     value-tag
                      type
0x001B                                     name-length
attributes-natural-   attributes-natural-  name
language              language
0x0005                                     value-length
en-US                 en-US                value
0x21                  integer type         value-tag
0x0005                                     name-length
limit                 limit                name
0x0004                                     value-length
0x00000032            50                   value

Moore and Turner          Expires May 7, 1998

Octets                Symbolic Value       Protocol field
0x44                  keyword type         value-tag
0x0014                                     name-length
requested-attributes  requested-attributes name
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
0x03                  start-data           data-tag

Moore and Turner         Expires April 23, 1998

9.7

10.7 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
0x0000            OK (successful)       status-code
0x01              start operation-      operation-attribute-tag
                  attributes
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      value-tag
                  type
0x001B                                  name-length
attributes-       attributes-natural-   name
natural-language  language
0x0005                                  value-length
en-US             en-US                 value
0x41              text type             value-tag
0x000E                                  name-length
status-message    status-message        name
0x0002                                  value-length
OK                OK                    value
0x02              start job-attributes  job-attributes-tag
                  (1st  object)
0x48              natural-language      value-tag
                  type
0x001B                                  name-length
attributes-       attributes-natural-   name
natural-language  language
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

Moore and Turner          Expires May 7, 1998

Octets            Symbolic Value        Protocol field
0x42              name type             value-tag
0x0008                                  name-length
job-name          job-name              name
0x0003                                  name-length
fou               fou                   name
0x02              start job-attributes  job-attributes-tag
                  (2nd object)
0x02              start job-attributes  job-attributes-tag
                  (3rd object)
0x21              interger              integer type          value-tag
0x0006                                  name-length
job-id            job-id                name

Moore and Turner         Expires April 23, 1998

Octets            Symbolic Value        Protocol field
0x0004                                  value-length
148               148                   value
0x13              compoundValue         value-tag
0x0008                                  name-length
job-name          job-name              name
0x0004                                  value-length
0x0002            2                     value (number of values)
0x48              naturalLanguage       value-tag
0x0000            muli-value            multi-value marker    name-length
0x0005                                  value-length
de-CH             de-CH                 value
0x42              name type             value-tag
0x0000            muli-value            multi-value marker    name-length
0x0003                                  name-length
bar               bar
isch guet         isch guet             name
0x03              start-data            data-tag

10.

11. Appendix B: Mapping of Each Operation in the Encoding

The next three tables show the results of applying the rules above to
the operations defined in the IPP model document. There is no
information in these tables that cannot be derived from the rules
presented in Section 3.8 "Mapping of Attribute  Names".

The following table shows the mapping of all IPP model-document request
attributes to an appropriate xxx-attribute-sequence  or special position
in the protocol.

The table below shows the attributes for operations sent to a Printer
URI.

Operation        operation       job attributes  special position
                 attributes

Print-Job        attributes-     job-template    document-content
                 charset         attributes
                 attributes-
                 natural-
                 language
                 job-name

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Operation        operation       job attributes  special position
                 attributes

                 document-name
                 ipp-attribute-
                 fidelity

                 document-
                 charset
                 document-
                 natural-
                 language
Create-Job or    attributes-     job-template
Validate-Job     charset         attributes
                 attributes-
                 natural-

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Operation        operation       job attributes  special position
                 attributes
                 language job-
                 name
                 ipp-attribute-
                 fidelity
Print-URI        attributes-     job-template
                 charset         attributes
                 attributes-
                 natural-
                 language job-
                 name
                 ipp-attribute-
                 fidelity
                 document-uri

                 document-
                 charset
                 document-
                 natural-
                 language
Send-Document    attributes-                     document-content
                 charset
                 attributes-
                 natural-
                 language job-id
                 last-document
                 document-name

                 document-
                 charset
                 document-
                 natural-                                                        document-content
                 language
Send-URI         attributes-
                 charset
                 attributes-
                 natural-
                 language job-id
                 last-document
                 document-name
                 document-uri

                 document-
                 charset
                 document-
                 natural-
                 language
Cancel-Job       attributes-
                 charset
                 attributes-
                 natural-
                 language job-id
                 message
Get-Attributes   attributes-

Moore and Turner          Expires April 23, May 7, 1998

Operation        operation       job attributes  special position
                 attributes

                 language
Cancel-Job       attributes-
                 charset
                 attributes-
                 natural-
                 language job-id
                 message
Get-Attributes   attributes-
(for a Printer)  charset
                 attributes-
                 natural-
                 language
                 requested-
                 attributes
                 document-format
Get-Attributes   attributes-
(for a Job)      charset
                 attributes-
                 natural-
                 language job-id
                 requested-
                 attributes
Get-Jobs         attributes-
                 charset
                 attributes-
                 natural-
                 language limit
                 requested-
                 attributes
                 which-jobs

The table below shows the attributes for operations sent to a Job URI.

Operation        operation       job attributes  special position
                 attributes

Send-Document    attributes-                     document-content
                 charset
                 attributes-
                 natural-
                 language last-
                 document
                 document-name

                 document-
                 charset
                 document-
                 natural-
                 language
Send-URI         attributes-
                 charset
                 attributes-
                 natural-
                 language last-
                 document
                 document-name
                 document-uri
                 document-

Moore and Turner          Expires April 23, May 7, 1998

Operation        operation       job attributes  special position
                 attributes

                 charset

                 attributes-
                 natural-
                 language last-
                 document
                 document-name
                 document-uri

                 document-
                 natural-
                 language
Cancel-Job       attributes-
                 charset
                 attributes-
                 natural-
                 language
                 message
Get-Attributes   attributes-
(for a Job)      charset
                 attributes-
                 natural-
                 language
                 requested-
                 attributes

The following two tables shows the mapping of all IPP model-document
response attributes to an appropriate xxx-attribute-sequence or special
position in the protocol.

Operation      operation     job-         unsupported-job-   special
               attributes    attributes   attributes         position

Print-Job,     attributes-   job-id       unsupported        status-
Print-URI,     charset       job-uri      attributes         code
Create-Job,    attributes-    job-state
Send-Document  natural-      job-state-
or Send-URI    language      reasons
               status-       job-state-
               message       message
                             number-of-
                             intervening
                             -jobs

Validate-Job   attributes-                unsupported        status-
               charset                    attributes         code
               attributes-
               natural-
               language
               status-

Moore and Turner          Expires May 7, 1998

Operation      operation     job-         unsupported-job-   special
               attributes    attributes   attributes         position

               message

Note: the unsupported-job-attributes are present only if the client
included some job attributes that the Printer doesn't support.

Moore and Turner         Expires April 23, 1998

Note:  the job-attributes are present only if the server returns the
status code of successful-ok or successful-ok-ignored-or-substituted-
attributes.

Operation      operation     job-         printer-      special
               attributes    attributes   attributes    position

Cancel-Job     attributes-
               charset
               attributes-
               natural-
               language
               status-                                                               status-code
               message

Get-Attributes attributes-   requested                  status-code
(of a job)     charset       attributes
               attributes-
               natural-
               language
               status-
               message

Get-Attributes attributes-                requested     status-code
(of a printer) charset                    attributes
               attributes-
               natural-
               language
               status-
               message

Get-Jobs       attributes-   requested                  status-code
               charset       attributes
               attributes-   (see the
               natural-      Note below)
               language
               status-
               message

Note for Get-Jobs: there is a separate job-attribute-sequence containing
requested-attributes for each job object in the response

11.

Moore and Turner          Expires May 7, 1998

12. Appendix C: Hints to implementors using IPP with SSL3

WARNING: Clients and IPP objects using intermediate secure connection
protocol solutions such as IPP in combination with Secure Socket Layer
Version 3 (SSL3), which are developed in advance of IPP and TLS
standardization, might not be interoperable with IPP and TLS standards-
conforming clients and IPP objects.

Moore and Turner         Expires April 23, 1998

An assumption is that the URI for a secure IPP Printer object has been
found by means outside the IPP printing protocol, via a directory
service, web site or other means.

IPP provides a transparent connection to SSL by calling the
corresponding URL (a https URI connects by default to port 443).
However, the following functions can be provided to ease the integration
of IPP with SSL during implementation.

connect (URI), returns a status.

  "connect" makes an https call and returns the immediate status of
  the connection as returned by SSL to the user. The status values are
  explained in section 5.4.2 of the SSL document [ssl].

  A session-id may also be retained to later resume a session.  The SSL
  handshake protocol may also require the cipher specifications
  supported by the client, key length of the ciphers, compression
  methods, certificates, etc. These should  be sent to the server and
  hence should be available to the IPP client (although as part of
  administration features).

disconnect (session)

  to disconnect a particular session.

  The session-id available from the "connect" could be used.

resume (session)

  to reconnect using a previous session-id.

The availability of this information as administration features are left
for implementors, and need not be standardized at this time

Moore and Turner          Expires April 23, May 7, 1998