IPP M. Sweet
Internet-Draft Apple Inc.
Obsoletes: 2910 (if approved) I. McDonald
Intended status: Standards Track High North, Inc.
Expires: October 27, 2015 April 25, 2015
Internet Printing Protocol/1.1: Encoding and Transport
draft-sweet-rfc2910bis-00
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. This document defines the
rules for encoding IPP operations and IPP attributes into a new
Internet mime media type called "application/ipp". This document
also defines the rules for transporting over HTTP a message body
whose Content-Type is "application/ipp". This document defines a new
scheme named 'ipp' for identifying IPP printers and jobs.
Editor's Note
This draft is being submitted in preparation for a so-called "fast
track" IETF IPP WG, with drafts being reviewed and edited by the
IEEE-ISTO's Printer Working Group IPP WG, in order to correct known
editorial issues and advance IPP/1.1 to IETF Internet Standard.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on October 27, 2015.
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Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conformance Terminology . . . . . . . . . . . . . . . . . . . 3
3. Encoding of the Operation Layer . . . . . . . . . . . . . . . 4
3.1. Picture of the Encoding . . . . . . . . . . . . . . . . . . 5
3.1.1. Request and Response . . . . . . . . . . . . . . . . . . 5
3.1.2. Attribute Group . . . . . . . . . . . . . . . . . . . . . 5
3.1.3. Attribute . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1.4. Picture of the Encoding of an Attribute-with-one-value . 6
3.1.5. Additional-value . . . . . . . . . . . . . . . . . . . . 7
3.1.6. Alternative Picture of the Encoding of a Request Or a
Response . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2. Syntax of Encoding . . . . . . . . . . . . . . . . . . . . 8
3.3. Attribute-group . . . . . . . . . . . . . . . . . . . . . . 10
3.4. Required Parameters . . . . . . . . . . . . . . . . . . . . 11
3.4.1. Version-number . . . . . . . . . . . . . . . . . . . . . 11
3.4.2. Operation-id . . . . . . . . . . . . . . . . . . . . . . 11
3.4.3. Status-code . . . . . . . . . . . . . . . . . . . . . . . 12
3.4.4. Request-id . . . . . . . . . . . . . . . . . . . . . . . 12
3.5. Tags . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.5.1. Delimiter Tags . . . . . . . . . . . . . . . . . . . . . 12
3.5.2. Value Tags . . . . . . . . . . . . . . . . . . . . . . . 14
3.6. Name-Length . . . . . . . . . . . . . . . . . . . . . . . . 17
3.7. (Attribute) Name . . . . . . . . . . . . . . . . . . . . . 17
3.8. Value Length . . . . . . . . . . . . . . . . . . . . . . . 17
3.9. (Attribute) Value . . . . . . . . . . . . . . . . . . . . . 18
3.10. Data . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4. Encoding of Transport Layer . . . . . . . . . . . . . . . . . 19
4.1. Printer-uri and job-uri . . . . . . . . . . . . . . . . . . 20
5. IPP URL Scheme . . . . . . . . . . . . . . . . . . . . . . . 21
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23
7. Internationalization Considerations . . . . . . . . . . . . . 24
8. Security Considerations . . . . . . . . . . . . . . . . . . . 24
8.1. Security Conformance Requirements . . . . . . . . . . . . . 24
8.1.1. Digest Authentication . . . . . . . . . . . . . . . . . . 24
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8.2. Using IPP with TLS . . . . . . . . . . . . . . . . . . . . 26
9. Interoperability with IPP/1.0 Implementations . . . . . . . . 26
9.1. The "version-number" Parameter . . . . . . . . . . . . . . 26
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 28
10.1. Normative References . . . . . . . . . . . . . . . . . . . 28
10.2. Informative References . . . . . . . . . . . . . . . . . . 30
Appendix A. Protocol Examples . . . . . . . . . . . . . . . . . 32
A.1. Print-Job Request . . . . . . . . . . . . . . . . . . . . . 32
A.2. Print-Job Response (successful) . . . . . . . . . . . . . . 33
A.3. Print-Job Response (failure) . . . . . . . . . . . . . . . 34
A.4. Print-Job Response (success with attributes ignored) . . . 36
A.5. Print-URI Request . . . . . . . . . . . . . . . . . . . . . 37
A.6. Create-Job Request . . . . . . . . . . . . . . . . . . . . 38
A.7. Get-Jobs Request . . . . . . . . . . . . . . . . . . . . . 39
A.8. Get-Jobs Response . . . . . . . . . . . . . . . . . . . . . 40
Appendix B. Registration of MIME Media Type Information for
"application/ipp" . . . . . . . . . . . . . . . . . 42
Appendix C. Changes from IPP/1.0 . . . . . . . . . . . . . . . . 43
Appendix D. Acknowledgements . . . . . . . . . . . . . . . . . . 44
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 45
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
2616 [RFC2616] 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/1.1: Model and
Semantics" [RFC2911] defines the semantics of such a message body and
the supported values. This document specifies the encoding of an IPP
operation. The aforementioned document [RFC2911] is henceforth
referred to as the "IPP model document" or simply "model document."
Note: the version number of IPP (1.1) and HTTP (1.1) are not linked.
They both just happen to be 1.1.
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].
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3. Encoding of the Operation Layer
The operation layer is the message body part of the HTTP request or
response and it MUST contain a single IPP operation request or IPP
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
SIGNED-SHORT are used for the operation-id, status-code and length
fields. Four byte integers, henceforth called SIGNED-INTEGER, are
used for value fields and the request-id.
The following two sections present the encoding of the operation
layer in two ways:
o informally through pictures and description
o formally through Augmented Backus-Naur Form (ABNF), as specified
by RFC 2234 [RFC2234]
An operation request or response MUST use the encoding described in
these two sections.
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3.1. Picture of the Encoding
3.1.1. Request and Response
An operation request or response is encoded as follows:
-----------------------------------------------
| version-number | 2 bytes - required
-----------------------------------------------
| operation-id (request) |
| or | 2 bytes - required
| status-code (response) |
-----------------------------------------------
| request-id | 4 bytes - required
-----------------------------------------------
| attribute-group | n bytes - 0 or more
-----------------------------------------------
| end-of-attributes-tag | 1 byte - required
-----------------------------------------------
| data | q bytes - optional
-----------------------------------------------
The first three fields in the above diagram contain the value of
attributes described in Section 3.1.1 of the Model document.
The fourth field is the "attribute-group" field, and it occurs 0 or
more times. Each "attribute-group" field represents a single group
of attributes, such as an Operation Attributes group or a Job
Attributes group (see the Model document). The IPP model document
specifies the required attribute groups and their order for each
operation request and response.
The "end-of-attributes-tag" field is always present, even when the
"data" is not present. The Model document specifies for each
operation request and response whether the "data" field is present or
absent.
3.1.2. Attribute Group
Each "attribute-group" field is encoded as follows:
-----------------------------------------------
| begin-attribute-group-tag | 1 byte
----------------------------------------------------------
| attribute | p bytes |- 0 or more
----------------------------------------------------------
An "attribute-group" field contains zero or more "attribute" fields.
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Note, the values of the "begin-attribute-group-tag" field and the
"end-of-attributes-tag" field are called "delimiter-tags".
3.1.3. Attribute
An "attribute" field is encoded as follows:
-----------------------------------------------
| attribute-with-one-value | q bytes
----------------------------------------------------------
| additional-value | r bytes |- 0 or more
----------------------------------------------------------
When an attribute is single valued (e.g. "copies" with value of 10)
or multi-valued with one value (e.g. "sides-supported" with just the
value 'one-sided') it is encoded with just an "attribute-with-one-
value" field. When an attribute is multi-valued with n values (e.g.
"sides-supported" with the values 'one-sided' and 'two-sided-long-
edge'), it is encoded with an "attribute-with-one-value" field
followed by n-1 "additional-value" fields.
3.1.4. Picture of the Encoding of an Attribute-with-one-value
Each "attribute-with-one-value" field is encoded as follows:
-----------------------------------------------
| 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 "attribute-with-one-value" field is encoded with five subfields:
o The "value-tag" field specifies the attribute syntax, e.g. 0x44
for the attribute syntax 'keyword'.
o The "name-length" field specifies the length of the "name" field
in bytes, e.g. u in the above diagram or 15 for the name "sides-
supported ".
o The "name" field contains the textual name of the attribute, e.g.
"sides-supported".
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o The "value-length" field specifies the length of the "value" field
in bytes, e.g. v in the above diagram or 9 for the (keyword) value
'one-sided'.
o The "value" field contains the value of the attribute, e.g. the
textual value 'one-sided'.
3.1.5. Additional-value
Each "additional-value" field is encoded as follows:
-----------------------------------------------
| value-tag | 1 byte
-----------------------------------------------
| name-length (value is 0x0000) | 2 bytes
-----------------------------------------------
| value-length (value is w) | 2 bytes
-----------------------------------------------
| value | w bytes
-----------------------------------------------
An "additional-value" is encoded with four subfields:
o The "value-tag" field specifies the attribute syntax, e.g. 0x44
for the attribute syntax 'keyword'.
o The "name-length" field has the value of 0 in order to signify
that it is an "additional-value". The value of the "name-length"
field distinguishes an "additional-value" field ("name-length" is
0) from an "attribute-with-one-value" field ("name-length" is not
0).
o The "value-length" field specifies the length of the "value" field
in bytes, e.g. w in the above diagram or 19 for the (keyword)
value 'two-sided-long-edge'.
o The "value" field contains the value of the attribute, e.g. the
textual value 'two-sided-long-edge'.
3.1.6. Alternative Picture of the Encoding of a Request Or a Response
From the standpoint of a parser that performs an action based on a
"tag" value, 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 | 1 byte - required
-----------------------------------------------
| data | y bytes - optional
-----------------------------------------------
The following show what fields the parser would expect after each
type of "tag":
o "begin-attribute-group-tag": expect zero or more "attribute"
fields
o "value-tag": expect the remainder of an "attribute-with-one-value"
or an "additional-value".
o "end-of-attributes-tag": expect that "attribute" fields are
complete and there is optional "data"
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.
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ipp-message = ipp-request / ipp-response
ipp-request = version-number operation-id request-id
*attribute-group end-of-attributes-tag data
ipp-response = version-number status-code request-id
*attribute-group end-of-attributes-tag data
attribute-group = begin-attribute-group-tag *attribute
version-number = major-version-number minor-version-number
major-version-number = SIGNED-BYTE
minor-version-number = SIGNED-BYTE
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
attribute = attribute-with-one-value *additional-value
attribute-with-one-value = value-tag name-length name
value-length value
additional-value = 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
value-tag = %x10-FF ;see section 3.7.2
begin-attribute-group-tag = %x00-02 / %04-0F ; see section 3.7.1
end-of-attributes-tag = %x03 ; tag of 3
; see section 3.7.1
SIGNED-BYTE = BYTE
SIGNED-SHORT = 2BYTE
SIGNED-INTEGER = 4BYTE
DIGIT = %x30-39 ; "0" to "9"
LALPHA = %x61-7A ; "a" to "z"
BYTE = %x00-FF
OCTET-STRING = *BYTE
The syntax below defines additional terms that are referenced in this
document. This syntax provides an alternate grouping of the
delimiter tags.
delimiter-tag = begin-attribute-group-tag / ; see section 3.7.1
end-of-attributes-tag
delimiter-tag = %x00-0F ; see section 3.7.1
begin-attribute-group-tag = %x00 / operation-attributes-tag /
job-attributes-tag / printer-attributes-tag /
unsupported-attributes-tag / %x06-0F
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
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3.3. Attribute-group
Each "attribute-group" field MUST be encoded with the "begin-
attribute-group-tag" field followed by zero or more "attribute" sub-
fields.
The table below maps the model document group name to value of the
"begin-attribute-group-tag" field:
+----------------+--------------------------------------------------+
| Model Document | "begin-attribute-group-tag" field values |
| Group | |
+----------------+--------------------------------------------------+
| Operation | "operations-attributes-tag" |
| Attributes | |
+----------------+--------------------------------------------------+
| Job Template | "job-attributes-tag" |
| Attributes | |
+----------------+--------------------------------------------------+
| Job Object | "job-attributes-tag" |
| Attributes | |
+----------------+--------------------------------------------------+
| Unsupported | "unsupported-attributes-tag" |
| Attributes | |
+----------------+--------------------------------------------------+
| Requested | (Get-Job-Attributes) "job-attributes-tag" |
| Attributes | |
+----------------+--------------------------------------------------+
| Requested | (Get-Printer-Attributes)"printer-attributes-tag" |
| Attributes | |
+----------------+--------------------------------------------------+
| Document | in a special position as described above |
| Content | |
+----------------+--------------------------------------------------+
For each operation request and response, the model document
prescribes the required and optional attribute groups, along with
their order. Within each attribute group, the model document
prescribes the required and optional attributes, along with their
order.
When the Model document requires an attribute group in a request or
response and the attribute group contains zero attributes, a request
or response SHOULD encode the attribute group with the "begin-
attribute-group-tag" field followed by zero "attribute" fields. For
example, if the client requests a single unsupported attribute with
the Get-Printer-Attributes operation, the Printer MUST return no
"attribute" fields, and it SHOULD return a "begin-attribute-group-
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tag" field for the Printer Attributes Group. The Unsupported
Attributes group is not such an example. According to the model
document, the Unsupported Attributes Group SHOULD be present only if
the unsupported attributes group contains at least one attribute.
A receiver of a request MUST be able to process the following as
equivalent empty attribute groups:
a. A "begin-attribute-group-tag" field with zero following
"attribute" fields.
b. An expected but missing "begin-attribute-group-tag" field.
When the Model document requires a sequence of an unknown number of
attribute groups, each of the same type, the encoding MUST contain
one "begin-attribute-group-tag" field for each attribute group even
when an "attribute-group" field contains zero "attribute" sub-fields.
For example, for the Get-Jobs operation may return zero attributes
for some jobs and not others. The "begin-attribute-group-tag" field
followed by zero "attribute" fields tells the recipient that there is
a job in queue for which no information is available except that it
is in the queue.
3.4. Required Parameters
Some operation elements are called parameters in the model document
[RFC2911]. They MUST be encoded in a special position and they MUST
NOT appear as operation attributes. These parameters are described
in the subsections below.
3.4.1. Version-number
The "version-number" field MUST consist of a major and minor version-
number, each of which MUST be represented by a SIGNED-BYTE. The
major version-number MUST be the first byte of the encoding and the
minor version-number MUST be the second byte of the encoding. The
protocol described in this document MUST have a major version-number
of 1 (0x01) and a minor version-number of 1 (0x01). The ABNF for
these two bytes MUST be %x01.01.
3.4.2. Operation-id
The "operation-id" field MUST contain an operation-id value defined
in the model document. The value MUST be encoded as a SIGNED-SHORT
and it MUST be in the third and fourth bytes of the encoding of an
operation request.
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3.4.3. Status-code
The "status-code" field MUST contain a status-code value defined in
the model document. The value MUST be encoded as a SIGNED-SHORT and
it MUST be in the third and fourth bytes of the encoding of an
operation response.
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 (successful-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.
3.4.4. Request-id
The "request-id" field MUST contain a request-id value as defined in
the model document. The value MUST be encoded as a SIGNED- INTEGER
and it MUST be in the fifth through eighth bytes of the encoding.
3.5. Tags
There are two kinds of tags:
o delimiter tags: delimit major sections of the protocol, namely
attributes and data
o value tags: specify the type of each attribute value
3.5.1. Delimiter Tags
The following table specifies the values for the delimiter tags:
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+--------------+----------------------------------------------------+
| Tag Value | Meaning |
| (Hex) | |
+--------------+----------------------------------------------------+
| 0x00 | reserved for definition in a future IETF standards |
| | track document |
+--------------+----------------------------------------------------+
| 0x01 | "operation-attributes-tag" |
+--------------+----------------------------------------------------+
| 0x02 | "job-attributes-tag" |
+--------------+----------------------------------------------------+
| 0x03 | "end-of-attributes-tag" |
+--------------+----------------------------------------------------+
| 0x04 | "printer-attributes-tag" |
+--------------+----------------------------------------------------+
| 0x05 | "unsupported-attributes-tag" |
+--------------+----------------------------------------------------+
| 0x06-0x0f | reserved for future delimiters in IETF standards |
| | track documents |
+--------------+----------------------------------------------------+
When a "begin-attribute-group-tag" field occurs in the protocol, it
means that zero or more following attributes up to the next delimiter
tag MUST be attributes belonging to the attribute group specified by
the value of the "begin-attribute-group-tag". For example, if the
value of "begin-attribute-group-tag" is 0x01, the following
attributes MUST be members of the Operations Attributes group.
The "end-of-attributes-tag" (value 0x03) MUST occur exactly once in
an operation. It MUST be the last "delimiter-tag". If the operation
has a document-content group, the document data in that group MUST
follow the "end-of-attributes-tag".
The order and presence of "attribute-group" fields (whose beginning
is marked by the "begin-attribute-group-tag" subfield) for each
operation request and each operation response MUST be that defined in
the model document. For further details, see Section 3.7
"(Attribute) Name" and 13 "Appendix A: Protocol Examples".
A Printer MUST treat a "delimiter-tag" (values from 0x00 through
0x0F) differently from a "value-tag" (values from 0x10 through 0xFF)
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.
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3.5.2. Value Tags
The remaining tables show values for the "value-tag" field, which is
the first octet of an attribute. The "value-tag" field specifies the
type of the value of the attribute.
The following table specifies the "out-of-band" values for the
"value-tag" field.
+------------+------------------------------------------------------+
| Tag Value | Meaning |
| (Hex) | |
+------------+------------------------------------------------------+
| 0x10 | unsupported |
+------------+------------------------------------------------------+
| 0x11 | reserved for 'default' for definition in a future |
| | IETF standards track document |
+------------+------------------------------------------------------+
| 0x12 | unknown |
+------------+------------------------------------------------------+
| 0x13 | no-value |
+------------+------------------------------------------------------+
| 0x14-0x1F | reserved for "out-of-band" values in future IETF |
| | standards track documents. |
+------------+------------------------------------------------------+
The following table specifies the integer values for the "value-tag"
field:
+------------+------------------------------------------------------+
| Tag Value | Meaning |
| (Hex) | |
+------------+------------------------------------------------------+
| 0x20 | reserved for definition in a future IETF standards |
| | track document |
+------------+------------------------------------------------------+
| 0x21 | integer |
+------------+------------------------------------------------------+
| 0x22 | boolean |
+------------+------------------------------------------------------+
| 0x23 | enum |
+------------+------------------------------------------------------+
| 0x24-0x2F | reserved for integer types for definition in future |
| | IETF standards track documents |
+------------+------------------------------------------------------+
NOTE: 0x20 is reserved for "generic integer" if it should ever be
needed.
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The following table specifies the octetString values for the "value-
tag" field:
+------------+------------------------------------------------------+
| Tag Value | Meaning |
| (Hex) | |
+------------+------------------------------------------------------+
| 0x30 | octetString with an unspecified format |
+------------+------------------------------------------------------+
| 0x31 | dateTime |
+------------+------------------------------------------------------+
| 0x32 | resolution |
+------------+------------------------------------------------------+
| 0x33 | rangeOfInteger |
+------------+------------------------------------------------------+
| 0x34 | reserved for definition in a future IETF standards |
| | track document |
+------------+------------------------------------------------------+
| 0x35 | textWithLanguage |
+------------+------------------------------------------------------+
| 0x36 | nameWithLanguage |
+------------+------------------------------------------------------+
| 0x37-0x3F | reserved for octetString type definitions in future |
| | IETF standards track documents |
+------------+------------------------------------------------------+
The following table specifies the character-string values for the
"value-tag" field:
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+------------+------------------------------------------------------+
| Tag Value | Meaning |
| (Hex) | |
+------------+------------------------------------------------------+
| 0x40 | reserved for definition in a future IETF standards |
| | track document |
+------------+------------------------------------------------------+
| 0x41 | textWithoutLanguage |
+------------+------------------------------------------------------+
| 0x42 | nameWithoutLanguage |
+------------+------------------------------------------------------+
| 0x43 | reserved for definition in a future IETF standards |
| | track document |
+------------+------------------------------------------------------+
| 0x44 | keyword |
+------------+------------------------------------------------------+
| 0x45 | uri |
+------------+------------------------------------------------------+
| 0x46 | uriScheme |
+------------+------------------------------------------------------+
| 0x47 | charset |
+------------+------------------------------------------------------+
| 0x48 | naturalLanguage |
+------------+------------------------------------------------------+
| 0x49 | mimeMediaType |
+------------+------------------------------------------------------+
| 0x4A-0x5F | reserved for character string type definitions in |
| | future IETF standards track documents |
+------------+------------------------------------------------------+
NOTE: 0x40 is reserved for "generic character-string" if it 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 type definitions in IETF
standards track documents.
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. Values from 0x00 to
0x37777777 are reserved for definition in future IETF standard track
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documents. The values 0x40000000 to 0x7FFFFFFF are reserved for
vendor extensions.
3.6. Name-Length
The "name-length" field MUST consist of a SIGNED-SHORT. This field
MUST specify the number of octets in the immediately following "name"
field. The value of this field excludes the two bytes of the "name-
length" field. For example, if the "name" field contains "sides",
the value of this field is 5.
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 attribute encoded in the nearest preceding
"attribute-with-one-value" field. Within an attribute group, if two
or more attributes have the same name, the attribute group is mal-
formed (see [RFC2911] Section 3.1.3). The zero-length name is the
only mechanism for multi-valued attributes.
3.7. (Attribute) Name
The "name " field MUST contain the name of an attribute. The model
document [RFC2911] specifies such names.
3.8. Value Length
The "value-length" field MUST consist of a SIGNED-SHORT. This field
MUST specify the number of octets in the immediately following
"value" field. The value of this field excludes the two bytes of the
"value-length" field. For example, if the "value" field contains the
keyword (text) value 'one-sided', the value of this field is 9.
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.
For "out-of-band" "value-tag" fields defined in this document, such
as "unsupported", the "value-length" MUST be 0 and the "value" empty;
the "value" has no meaning when the "value-tag" has one of these
"out-of-band" values. For future "out-of-band" "value-tag" fields,
the same rule holds unless the definition explicitly states that the
"value-length" MAY be non-zero and the "value" non-empty
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3.9. (Attribute) Value
The syntax types (specified by the "value-tag" field) and most of the
details of the representation of attribute values 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, and 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, and 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, | |
| keyword, uri, and | |
| uriScheme | |
+----------------------+--------------------------------------------+
| boolean | SIGNED-BYTE where 0x00 is 'false' and 0x01 |
| | is 'true' |
+----------------------+--------------------------------------------+
| integer and enum | a SIGNED-INTEGER |
+----------------------+--------------------------------------------+
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| 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-INTEGER |
| | contains the lower bound and the second |
| | SIGNED-INTEGER 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 attribute syntax type of the value determines its encoding and
the value of its "value-tag".
3.10. Data
The "data" field MUST include any data required by the operation.
4. Encoding of Transport Layer
HTTP/1.1 [RFC2616] is the transport layer for this protocol.
The operation layer has been designed with the assumption that the
transport layer contains the following information:
o the URI of the target job or printer operation
o 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 some other port as well.
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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
for HTTP1.1 [RFC2616] . A printer (server) implementation MUST adhere
the rules for an origin server described for HTTP1.1 [RFC2616].
An IPP server sends a response for each request that it receives. If
an IPP server detects an error, it MAY send a response before it has
read the entire request. If the HTTP layer of the IPP server
completes processing the HTTP headers successfully, it MAY send an
intermediate response, such as "100 Continue", with no IPP data
before sending the IPP response. A client MUST expect such a variety
of responses from an IPP server. For further information on
HTTP/1.1, consult the HTTP documents [RFC2616].
An HTTP server MUST support chunking for IPP requests, and an IPP
client MUST support chunking for IPP responses according to
HTTP/1.1[RFC2616]. Note: this rule causes a conflict with non-
compliant implementations of HTTP/1.1 that don't support chunking for
POST methods, and this rule may cause a conflict with non-compliant
implementations of HTTP/1.1 that don't support chunking for CGI
scripts
4.1. Printer-uri and job-uri
All Printer and Job objects are identified by a Uniform Resource
Identifier (URI) [RFC2396] 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 and are called printer-uri and job-uri.
Note: The target URI is included twice in an operation referencing
the same IPP object, but the two URIs NEED NOT be 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
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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 attribute and as a URI at
the HTTP layer. The rationale for this decision is to maintain a
consistent set of rules for mapping application/ipp to possibly
many communication layers, even where URLs are not used as the
addressing mechanism in the transport layer.
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. However, a Printer NEED NOT
verify that the two URLs reference the same IPP object, and NEED
NOT take any action if it determines the two URLs to be
different.
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.
5. IPP URL Scheme
The IPP/1.1 document defines a new scheme 'ipp' as the value of a URL
that identifies either an IPP printer object or an IPP job object.
The IPP attributes using the 'ipp' scheme are specified below.
Because the HTTP layer does not support the 'ipp' scheme, a client
MUST map 'ipp' URLs to 'http' URLs, and then follows the HTTP
[RFC2616][RFC2617] rules for constructing a Request-Line and HTTP
headers. The mapping is simple because the 'ipp' scheme implies all
of the same protocol semantics as that of the 'http' scheme
[RFC2616], except that it represents a print service and the implicit
(default) port number that clients use to connect to a server is port
631.
In the remainder of this section the term 'ipp-URL' means a URL whose
scheme is 'ipp' and whose implicit (default) port is 631. The term
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'http-URL' means a URL whose scheme is 'http', and the term 'https-
URL' means a URL whose scheme is 'https'.
A client and an IPP object (i.e. the server) MUST support the ipp-URL
value in the following IPP attributes:
o job attributes:
* job-uri
* job-printer-uri
o printer attributes:
* printer-uri-supported
o operation attributes:
* job-uri
* printer-uri
Each of the above attributes identifies a printer or job object. The
ipp-URL is intended as the value of the attributes in this list, and
for no other attributes. All of these attributes have a syntax type
of 'uri', but there are attributes with a syntax type of 'uri' that
do not use the 'ipp' scheme, e.g. 'job-more-info'.
If a printer registers its URL with a directory service, the printer
MUST register an ipp-URL.
User interfaces are beyond the scope of this document. But if
software exposes the ipp-URL values of any of the above five
attributes to a human user, it is REQUIRED that the human see the
ipp-URL as is.
When a client sends a request, it MUST convert a target ipp-URL to a
target http-URL for the HTTP layer according to the following rules:
1. change the 'ipp' scheme to 'http'
2. add an explicit port 631 if the URL does not contain an explicit
port. Note: port 631 is the IANA assigned Well Known Port for
the 'ipp' scheme.
The client MUST use the target http-URL in both the HTTP Request-Line
and HTTP headers, as specified by HTTP[RFC2616][RFC2617] . However,
the client MUST use the target ipp-URL for the value of the "printer-
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uri" or "job-uri" operation attribute within the application/ipp body
of the request. The server MUST use the ipp-URL for the value of the
"printer-uri", "job-uri" or "printer-uri-supported" attributes within
the application/ipp body of the response.
For example, when an IPP client sends a request directly (i.e. no
proxy) to an ipp-URL "ipp://myhost.com/myprinter/myqueue", it opens a
TCP connection to port 631 (the ipp implicit port) on the host
"myhost.com" and sends the following data:
POST /myprinter/myqueue HTTP/1.1
Host: myhost.com:631
Content-type: application/ipp
Transfer-Encoding: chunked
...
"printer-uri" "ipp://myhost.com/myprinter/myqueue"
(encoded in application/ipp message body)
...
As another example, when an IPP client sends the same request as
above via a proxy "myproxy.com", it opens a TCP connection to the
proxy port 8080 on the proxy host "myproxy.com" and sends the
following data:
POST http://myhost.com:631/myprinter/myqueue HTTP/1.1
Host: myhost.com:631
Content-type: application/ipp
Transfer-Encoding: chunked
...
"printer-uri" "ipp://myhost.com/myprinter/myqueue"
(encoded in application/ipp message body)
...
The proxy then connects to the IPP origin server with headers that
are the same as the "no-proxy" example above.
6. IANA Considerations
This section describes the procedures for allocating encoding for the
following IETF standards track extensions and vendor extensions to
the IPP/1.1 Encoding and Transport document:
1. attribute syntaxes - see [RFC2911] section 6.3
2. attribute groups - see [RFC2911] section 6.5
3. out-of-band attribute values - see [RFC2911] section 6.7
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These extensions follow the "type2" registration procedures defined
in [RFC2911] Section 6. Extensions registered for use with IPP/1.1
are OPTIONAL for client and IPP object conformance to the IPP/1.1
Encoding and Transport document.
These extension procedures are aligned with the guidelines as set
forth by the IESG [IANA-CON]. The [RFC2911] describes how to propose
new registrations for consideration. IANA will reject registration
proposals that leave out required information or do not follow the
appropriate format described in [RFC2911]. The IPP/1.1 Encoding and
Transport document may also be extended by an appropriate RFC that
specifies any of the above extensions.
7. Internationalization Considerations
See the section on "Internationalization Considerations" in the
document "Internet Printing Protocol/1.1: Model and Semantics"
[RFC2911] for information on internationalization. This document
adds no additional issues.
8. Security Considerations
The IPP Model and Semantics document [RFC2911] discusses high level
security requirements (Client Authentication, Server Authentication
and Operation Privacy). Client Authentication is the mechanism by
which the client proves its identity to the server in a secure
manner. Server Authentication is the mechanism by which the server
proves its identity to the client in a secure manner. Operation
Privacy is defined as a mechanism for protecting operations from
eavesdropping.
8.1. Security Conformance Requirements
This section defines the security requirements for IPP clients and
IPP objects.
8.1.1. Digest Authentication
IPP clients MUST support:
Digest Authentication [RFC2617].
MD5 and MD5-sess MUST be implemented and supported.
The Message Integrity feature NEED NOT be used.
IPP Printers SHOULD support:
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Digest Authentication [RFC2617].
MD5 and MD5-sess MUST be implemented and supported.
The Message Integrity feature NEED NOT be used.
The reasons that IPP Printers SHOULD (rather than MUST) support
Digest Authentication are:
1. While Client Authentication is important, there is a certain
class of printer devices where it does not make sense.
Specifically, a low-end device with limited ROM space and low
paper throughput may not need Client Authentication. This class
of device typically requires firmware designers to make trade-
offs between protocols and functionality to arrive at the lowest-
cost solution possible. Factored into the designer's decisions
is not just the size of the code, but also the testing,
maintenance, usefulness, and time-to-market impact for each
feature delivered to the customer. Forcing such low-end devices
to provide security in order to claim IPP/1.1 conformance would
not make business sense and could potentially stall the adoption
of the standard.
2. Print devices that have high-volume throughput and have available
ROM space have a compelling argument to provide support for
Client Authentication that safeguards the device from
unauthorized access. These devices are prone to a high loss of
consumables and paper if unauthorized access should occur.
8.1.2 Transport Layer Security (TLS)
IPP Printers SHOULD support Transport Layer Security (TLS) [RFC2246]
for Server Authentication and Operation Privacy. IPP Printers MAY
also support TLS for Client Authentication. If an IPP Printer
supports TLS, it MUST support the TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA
cipher suite as mandated by RFC 2246 [RFC2246]. All other cipher
suites are OPTIONAL. An IPP Printer MAY support Basic Authentication
(described in HTTP/1.1 [RFC2617]) for Client Authentication if the
channel is secure. TLS with the above mandated cipher suite can
provide such a secure channel.
If a IPP client supports TLS, it MUST support the
TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA cipher suite as mandated by RFC
2246 [RFC2246]. All other cipher suites are OPTIONAL.
The IPP Model and Semantics document defines two printer attributes
("uri-authentication-supported" and "uri-security-supported") that
the client can use to discover the security policy of a printer.
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That document also outlines IPP-specific security considerations and
should be the primary reference for security implications with regard
to the IPP protocol itself. For backward compatibility with IPP
version 1.0, IPP clients and printers may also support SSL3 [SSL].
This is in addition to the security required in this document.
8.2. Using IPP with TLS
IPP/1.1 uses the "Upgrading to TLS Within HTTP/1.1" mechanism
[RFC2817]. An initial IPP request never uses TLS. The client
requests a secure TLS connection by using the HTTP "Upgrade" header,
while the server agrees in the HTTP response. The switch to TLS
occurs either because the server grants the client's request to
upgrade to TLS, or a server asks to switch to TLS in its response.
Secure communication begins with a server's response to switch to
TLS.
9. Interoperability with IPP/1.0 Implementations
It is beyond the scope of this specification to mandate conformance
with previous versions. IPP/1.1 was deliberately designed, however,
to make supporting previous versions easy. It is worth noting that,
at the time of composing this specification (1999), we would expect
IPP/1.1 Printer implementations to:
understand any valid request in the format of IPP/1.0, or 1.1;
respond appropriately with a response containing the same "version-
number" parameter value used by the client in the request.
And we would expect IPP/1.1 clients to:
understand any valid response in the format of IPP/1.0, or 1.1.
9.1. The "version-number" Parameter
The following are rules regarding the "version-number" parameter (see
Section 3.3):
1. Clients MUST send requests containing a "version-number"
parameter with a '1.1' value and SHOULD try supplying alternate
version numbers if they receive a 'server-error-version-not-
supported' error return in a response.
2. IPP objects MUST accept requests containing a "version-number"
parameter with a '1.1' value (or reject the request for reasons
other than 'server-error-version-not-supported').
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3. It is recommended that IPP objects accept any request with the
major version '1' (or reject the request for reasons other than
'server-error-version-not-supported'). See [RFC2911] "versions"
sub-section.
4. In any case, security MUST NOT be compromised when a client
supplies a lower "version-number" parameter in a request. For
example, if an IPP/1.1 conforming Printer object accepts version
'1.0' requests and is configured to enforce Digest
Authentication, it MUST do the same for a version '1.0' request.
9.2 Security and URL Schemes
The following are rules regarding security, the "version-number"
parameter, and the URL scheme supplied in target attributes and
responses:
1. When a client supplies a request, the "printer-uri" or "job-uri"
target operation attribute MUST have the same scheme as that
indicated in one of the values of the "printer-uri-supported"
Printer attribute.
2. When the server returns the "job-printer-uri" or "job-uri" Job
Description attributes, it SHOULD return the same scheme ('ipp',
'https', 'http', etc.) that the client supplied in the "printer-
uri" or "job-uri" target operation attributes in the Get-Job-
Attributes or Get-Jobs request, rather than the scheme used when
the job was created. However, when a client requests job
attributes using the Get-Job-Attributes or Get-Jobs operations,
the jobs and job attributes that the server returns depends on:
(1) the security in effect when the job was created, (2) the
security in effect in the query request, and (3) the security
policy in force.
3. It is recommended that if a server registers a non-secure ipp-URL
with a directory service (see [RFC2911] "Generic Directory
Schema" Appendix), then it also register an http-URL for
interoperability with IPP/1.0 clients (see Section 9).
4. In any case, security MUST NOT be compromised when a client
supplies an 'http' or other non-secure URL scheme in the target
"printer-uri" and "job-uri" operation attributes in a request.
5. . References
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10. References
10.1. Normative References
[ASCII] ANSI, "Information Systems - Coded Character Sets - 7-Bit
American National Standard Code for Information
Interchange (7-Bit ASCII)", June 2007.
[ASME-Y14.1M]
"ASME Y14.1M-1995: Metric Drawing Sheet Size and Format",
1995.
[IPP-IIG] Hastings, T., Manros, C., Zehler, P., Kugler, C., and H.
Holst, "Internet Printing Protocol/1.1: Implementor's
Guide", RFC 3196, November 2001.
[ISO10175]
"ISO/IEC 10175 Document Printing Application (DPA)", June
1996.
[ISO10646-1]
"ISO/IEC 10646-1:1993, "Information technology --
Universal Multiple-Octet Coded Character Set (UCS) - Part
1: Architecture and Basic Multilingual Plane, JTC1/SC2."",
1993.
[ISO8859-1]
"ISO/IEC 8859-1:1987, "Information technology -- 8-bit
One-Byte Coded Character Set - Part 1: Latin Alphabet Nr
1"", 1987.
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC1738] Berners-Lee, T., Masinter, L., and M. McCahill, "Uniform
Resource Locators (URL)", RFC 1738, December 1994.
[RFC1759] Smith, R., Wright, F., Hastings, T., Zilles, S., and J.
Gyllenskog, "Printer MIB", RFC 1759, March 1995.
[RFC1766] Alvestrand, H., "Tags for the Identification of
Languages", RFC 1766, March 1995.
[RFC1808] Fielding, R., "Relative Uniform Resource Locators", RFC
1808, June 1995.
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[RFC1903] McCloghrie, K., Case, J., Rose, M., and S. Waldbusser,
"Textual Conventions for Version 2 of the Simple Network
Management Protocol (SNMPv2)", RFC 1903, January 1996.
[RFC1951] Deutsch, P., "DEFLATE Compressed Data Format Specification
version 1.3", RFC 1951, May 1996.
[RFC1952] Deutsch, P., Gailly, J-L., Adler, M., Deutsch, L., and G.
Randers-Pehrson, "GZIP file format specification version
4.3", RFC 1952, May 1996.
[RFC1977] Schryver, V., "PPP BSD Compression Protocol", RFC 1977,
August 1996.
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, November 1996.
[RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types", RFC 2046,
November 1996.
[RFC2048] Freed, N., Klensin, J., and J. Postel, "Multipurpose
Internet Mail Extensions (MIME) Part Four: Registration
Procedures", BCP 13, RFC 2048, November 1996.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC 2234, November 1997.
[RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
RFC 2246, January 1999.
[RFC2279] Yergeau, F., "UTF-8, a transformation format of ISO
10646", RFC 2279, January 1998.
[RFC2396] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifiers (URI): Generic Syntax", RFC 2396,
August 1998.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
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[RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S.,
Leach, P., Luotonen, A., and L. Stewart, "HTTP
Authentication: Basic and Digest Access Authentication",
RFC 2617, June 1999.
[RFC2817] Khare, R. and S. Lawrence, "Upgrading to TLS Within
HTTP/1.1", RFC 2817, May 2000.
[RFC2910] Herriot, R., Butler, S., Moore, P., Turner, R., and J.
Wenn, "Internet Printing Protocol/1.1: Encoding and
Transport", RFC 2910, September 2000.
[RFC2911] Hastings, T., Herriot, R., deBry, R., Isaacson, S., and P.
Powell, "Internet Printing Protocol/1.1: Model and
Semantics", RFC 2911, September 2000.
10.2. Informative References
[BCP-11] Hovey, R. and S. Bradner, "The Organizations Involved in
the IETF Standards Process", BCP 11, RFC 2028, October
1996.
[HTPP] Barnett, J., Carter, K., and R. DeBry, "Initial Draft -
Hypertext Printing Protocol - HTPP/1.0", 10 1996,
<ftp://ftp.pwg.org/pub/pwg/ipp/historic/htpp/
overview.ps.gz>.
[IANA-CON]
Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
[IANA-CS] "IANA Registry of Coded Character Sets",
<ftp://ftp.isi.edu/in-notes/iana/assignments/character-
sets>.
[IANA-MT] "IANA Registry of Media Types", <ftp://ftp.isi.edu/in-
notes/iana/assignments/media-types/>.
[LDPA] Hastings, T., Isaacson, S., MacKay, M., Manros, C.,
Taylor, D., and P. Zehler, "LDPA - Lightweight Document
Printing Application", October 1996,
<ftp://ftp.pwg.org/pub/pwg/ipp/historic/ldpa/
ldpa8.pdf.gz>.
[PSIS] Herriot, R., "X/Open: A Printing System Interoperability
Specification (PSIS)", August 1995.
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[PWG] "The Printer Working Group, a program of the IEEE-ISTO",
<http://www.pwg.org/>.
[RFC1179] McLaughlin, L., "Line printer daemon protocol", RFC 1179,
August 1990.
[RFC2026] Bradner, S., "The Internet Standards Process -- Revision
3", BCP 9, RFC 2026, October 1996.
[RFC2228] Horowitz, M., "FTP Security Extensions", RFC 2228, October
1997.
[RFC2277] Alvestrand, H., "IETF Policy on Character Sets and
Languages", BCP 18, RFC 2277, January 1998.
[RFC2278] Freed, N. and J. Postel, "IANA Charset Registration
Procedures", BCP 19, RFC 2278, January 1998.
[RFC2316] Bellovin, S., "Report of the IAB Security Architecture
Workshop", RFC 2316, April 1998.
[RFC2565] Herriot, R., Butler, S., Moore, P., and R. Turner,
"Internet Printing Protocol/1.0: Encoding and Transport",
RFC 2565, April 1999.
[RFC2566] deBry, R., Hastings, T., Herriot, R., Isaacson, S., and P.
Powell, "Internet Printing Protocol/1.0: Model and
Semantics", RFC 2566, April 1999.
[RFC2567] Wright, F., "Design Goals for an Internet Printing
Protocol", RFC 2567, April 1999.
[RFC2568] Zilles, S., "Rationale for the Structure of the Model and
Protocol for the Internet Printing Protocol", RFC 2568,
April 1999.
[RFC2569] Herriot, R., Jacobs, N., Hastings, T., and J. Martin,
"Mapping between LPD and IPP Protocols", RFC 2569, April
1999.
[RFC2579] McCloghrie, K., Ed., Perkins, D., Ed., and J.
Schoenwaelder, Ed., "Textual Conventions for SMIv2", STD
58, RFC 2579, April 1999.
[RFC2639] Hastings, T. and C. Manros, "Internet Printing
Protocol/1.0: Implementer's Guide", RFC 2639, July 1999.
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[SSL] "The SSL Protocol, Version 3, (Text version 3.02)",
November 1996.
[SWP] Moore, P., Jahromi, B., and S. Butler, "Simple Web
Printing SWP/1.0", May 1997,
<ftp://ftp.pwg.org/pub/pwg/ipp/new_PRO/swp9705.pdf>.
Appendix A. Protocol Examples
A.1. Print-Job Request
The following is an example of a Print-Job request with job-name,
copies, and sides specified. The "ipp-attribute-fidelity" attribute
is set to 'true' so that the print request will fail if the "copies"
or the "sides" attribute are not supported or their values are not
supported.
Octets Symbolic Value Protocol field
0x0101 1.1version-number 0x0002
Print-Job operation-id 0x00000001
1 request-id 0x01
start operation- operation- 0x47
attributes attributes-tag
charset type value-tag 0x0012
name-length attributes-charset
attributes-charset name 0x0008
value-length us-ascii
US-ASCII value 0x48
natural-language type value-tag 0x001B
name-length attributes-natural-
language
attributes-natural- name 0x0005
language
value-length en-us
en-US value 0x45
uri type value-tag 0x000B
name-length printer-uri
printer-uri name 0x0015
value-length ipp://forest/pinetree
printer pinetree value 0x42
nameWithoutLanguage value-tag 0x0008
type
name-length job-name
job-name name 0x0006
value-length foobar
foobar value 0x22
boolean type value-tag 0x0016
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name-length ipp-attribute-fidelity
ipp-attribute-fidelity name 0x0001
value-length 0x01
true value 0x02
start job-attributes job-attributes-tag 0x21
integer type value-tag 0x0006
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
end-of-attributes end-of-attributes- %!PS...
tag
<PostScript> data
A.2. Print-Job Response (successful)
Here is an example of a successful Print-Job response to the previous
Print-Job request. The printer supported the "copies" and "sides"
attributes and their supplied values. The status code returned is
'successful-ok'.
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Octets Symbolic Value Protocol field
0x0101 1.1 version-number
0x0000 successful-ok status-code
0x00000001 1 request-id
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 type value-tag
0x001B name-length
attributes-natural- attributes-natural- name
language language
0x0005 value-length
en-us en-US value
0x41 textWithoutLanguage value-tag
type
0x000E name-length
status-message status-message name
0x000D value-length
successful-ok successful-ok value
0x02 start job-attributes job-attributes-tag
0x21 integer value-tag
0x0006 name-length
job-id job-id name
0x0004 value-length
147 147 value
0x45 uri type value-tag
0x0007 name-length
job-uri job-uri name
0x0019 value-length
ipp://forest/pinetree/1 job 123 on pinetree value
23
0x23 enum type value-tag
0x0009 name-length
job-state job-state name
0x0004 value-length
0x0003 pending value
0x03 end-of-attributes end-of-attributes-tag
A.3. Print-Job Response (failure)
Here is an example of an unsuccessful Print-Job response to the
previous Print-Job request. It fails because, in this case, the
printer does not support the "sides" attribute and because the value
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'20' for the "copies" attribute is not supported. Therefore, no job
is created, and neither a "job-id" nor a "job-uri" operation
attribute is returned. The error code returned is 'client-error-
attributes-or-values-not-supported' (0x040B).
Octets Symbolic Value Protocol
field
0x0101 1.1 version-
number
0x040B client-error-attributes-or- status-code
values-not-supported
0x00000001 1 request-id
0x01 start operation-attributes operation-
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 type value-tag
0x001B name-length
attributes-natural-language attributes-natural-language name
0x0005 value-length
en-us en-US value
0x41 textWithoutLanguage type value-tag
0x000E name-length
status-message status-message name
0x002F value-length
client-error-attributes-or- client-error-attributes-or- value
values-not-supported values-not-supported
0x05 start unsupported- unsupported-
attributes attributes
tag
0x21 integer type value-tag
0x0006 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
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A.4. Print-Job Response (success with attributes ignored)
Here is an example of a successful Print-Job response to a Print-Job
request like the previous Print-Job request, except that the value of
'ipp-attribute-fidelity' is false. The print request succeeds, even
though, in this case, the printer supports neither the "sides"
attribute nor the value '20' for the "copies" attribute. Therefore,
a job is created, and both a "job-id" and a "job-uri" operation
attribute are returned. The unsupported attributes are also returned
in an Unsupported Attributes Group. The error code returned is
'successful-ok-ignored-or-substituted-attributes' (0x0001).
Octets Symbolic Value Protocol field
0x0101 1.1 version-number
0x0001 successful-ok-ignored-or- status-code
substituted-attributes
0x00000001 1 request-id
0x01 start operation-attributes operation-
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 type value-tag
0x001B name-length
attributes-natural- attributes-natural-language name
language
0x0005 value-length
en-us en-US value
0x41 textWithoutLanguage type value-tag
0x000E name-length
status-message status-message name
0x002F value-length
successful-ok-ignored-or- successful-ok-ignored-or- value
substituted-attributes substituted-attributes
0x05 start unsupported- unsupported-
attributes attributes tag
0x21 integer type value-tag
0x0006 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
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0x02 start job-attributes job-
attributes-tag
0x21 integer value-tag
0x0006 name-length
job-id job-id name
0x0004 value-length
147 147 value
0x45 uri type value-tag
0x0007 name-length
job-uri job-uri name
0x0019 value-length
ipp://forest/pinetree/123 job 123 on pinetree value
0x23 enum type value-tag
0x0009 name-length
job-state job-state name
0x0004 value-length
0x0003 pending value
0x03 end-of-attributes end-of-
attributes-tag
A.5. 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
0x0101 1.1 version-number
0x0003 Print-URI operation-id
0x00000001 1 request-id
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 type value-tag
0x001B name-length
attributes-natural- attributes-natural- name
language language
0x0005 value-length
en-us en-US value
0x45 uri type value-tag
0x000B name-length
printer-uri printer-uri name
0x0015 value-length
ipp://forest/pinetree printer pinetree value
0x45 uri type value-tag
0x000C name-length
document-uri document-uri name
0x0011 value-length
ftp://foo.com/foo ftp://foo.com/foo value
0x42 nameWithoutLanguage value-tag
type
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
0x0006 name-length
copies copies name
0x0004 value-length
0x00000001 1 value
0x03 end-of-attributes end-of-attributes-tag
A.6. Create-Job Request
The following is an example of Create-Job request with no parameters
and no attributes:
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Octets Symbolic Value Protocol field
0x0101 1.1 version-number
0x0005 Create-Job operation-id
0x00000001 1 request-id
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 type value-tag
0x001B name-length
attributes-natural- attributes-natural- name
language language
0x0005 value-length
en-us en-US value
0x45 uri type value-tag
0x000B name-length
printer-uri printer-uri name
0x0015 value-length
ipp://forest/pinetree printer pinetree value
0x03 end-of-attributes end-of-attributes-tag
A.7. Get-Jobs Request
The following is an example of Get-Jobs request with parameters but
no attributes:
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Octets Symbolic Value Protocol field
0x0101 1.1 version-number
0x000A Get-Jobs operation-id
0x00000123 0x123 request-id
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 type value-tag
0x001B name-length
attributes-natural- attributes-natural- name
language language
0x0005 value-length
en-us en-US value
0x45 uri type value-tag
0x000B name-length
printer-uri printer-uri name
0x0015 value-length
ipp://forest/pinetree printer pinetree value
0x21 integer type value-tag
0x0005 name-length
limit limit name
0x0004 value-length
0x00000032 50 value
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
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
A.8. 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
(because of security reasons):
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Octets Symbolic Value Protocol field
0x0101 1.1 version-number
0x0000 successful-ok status-code
0x00000123 0x123 request-id (echoed
back)
0x01 start operation- operation-attributes-
attributes tag
0x47 charset type value-tag
0x0012 name-length
attributes-charset attributes-charset name
0x000A value-length
ISO-8859-1 ISO-8859-1 value
0x48 natural-language type value-tag
0x001B name-length
attributes-natural- attributes-natural- name
language language
0x0005 value-length
en-us en-US value
0x41 textWithoutLanguage value-tag
type
0x000E name-length
status-message status-message name
0x000D value-length
successful-ok successful-ok value
0x02 start job-attributes job-attributes-tag
(1st object)
0x21 integer type value-tag
0x0006 name-length
job-id job-id name
0x0004 value-length
147 147 value
0x36 nameWithLanguage value-tag
0x0008 name-length
job-name job-name name
0x000C value-length
0x0005 sub-value-length
fr-ca fr-CA value
0x0003 sub-value-length
fou fou name
0x02 start job-attributes job-attributes-tag
(2nd object)
0x02 start job-attributes job-attributes-tag
(3rd object)
0x21 integer type value-tag
0x0006 name-length
job-id job-id name
0x0004 value-length
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148 149 value
0x36 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
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/1.1, whose syntax is described in Section 3 "Encoding of
the Operation Layer" of [RFC2910], and whose semantics are described
in [RFC2911].
Required parameters: none
Optional parameters: none
Encoding considerations:
IPP/1.1 protocol requests/responses MAY contain long lines and ALWAYS
contain binary data (for example attribute value lengths).
Security considerations:
IPP/1.1 protocol requests/responses do not introduce any security
risks not already inherent in the underlying transport protocols.
Protocol mixed-version interworking rules in [RFC2911] as well as
protocol encoding rules in [RFC2910] are complete and unambiguous.
Interoperability considerations:
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IPP/1.1 requests (generated by clients) and responses (generated by
servers) MUST comply with all conformance requirements imposed by the
normative specifications [RFC2911] and [RFC2910]. Protocol encoding
rules specified in [RFC2910] 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/1.1 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 specifications:
[RFC2911] Isaacson, S., deBry, R., Hastings, T., Herriot, R.,
Powell, P., "Internet Printing Protocol/1.1: Model and Semantics"
draft-ietf-ipp-model-v11-07.txt, May 22, 2000.
[RFC2910] Herriot, R., Butler, S., Moore, P., Turner, R., "Internet
Printing Protocol/1.1: Encoding and Transport", draft-ietf-ipp-
protocol-v11-06.txt, May 30, 2000.
Applications which use this media type:
Internet Printing Protocol (IPP) print clients and print servers,
communicating using HTTP/1.1 (see [RFC2910]), 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.
Appendix C. Changes from IPP/1.0
IPP/1.1 is identical to IPP/1.0 [RFC2565] with the follow changes:
1. Attributes values that identify a printer or job object use a new
'ipp' scheme. The 'http' and 'https' schemes are supported only
for backward compatibility. See section 5.
2. Clients MUST support of Digest Authentication, IPP Printers
SHOULD support Digest Authentication. See Section 8.1.1
3. TLS is recommended for channel security. In addition, SSL3 may
be supported for backward compatibility. See Section 8.1.2
4. It is recommended that IPP/1.1 objects accept any request with
major version number '1'. See Section 9.1.
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5. IPP objects SHOULD return the URL scheme requested for "job-
printer-uri" and "job-uri" Job Attributes, rather than the URL
scheme used to create the job. See section 9.2.
6. The IANA and Internationalization sections have been added. The
terms "private use" and "experimental" have been changed to
"vendor extension". The reserved allocations for attribute group
tags, attribute syntax tags, and out-of-band attribute values
have been clarified as to which are reserved to future IETF
standards track documents and which are reserved to vendor
extension. Both kinds of extensions use the type2 registration
procedures as defined in [RFC2911].
7. Clarified that future "out-of-band" value definitions may use the
value field if additional information is needed.
Appendix D. Acknowledgements
The authors would like to acknowledge the following individuals for
their contributions to the original IPP/1.1 specification:
Robert Herriot (original RFC 2910 editor) - Xerox Corporation, Paul
Moore - Peerless Systems Networking, Sylvan Butler - Hewlett-Packard,
Randy Turner - 2Wire, Inc., John Wenn - Xerox Corporation, Chuck
Adams - Tektronix, Shivaun Albright - HP, Stefan Andersson - Axis,
Jeff Barnett - IBM, Ron Bergman - Hitachi Koki Imaging Systems,
Dennis Carney - IBM, Keith Carter - IBM, Angelo Caruso - Xerox,
Rajesh Chawla - TR Computing Solutions, Nancy Chen - Okidata, Josh
Cohen - Microsoft, Jeff Copeland - QMS, Andy Davidson - Tektronix,
Roger deBry - IBM, Maulik Desai - Auco, Mabry Dozier - QMS, Lee
Farrell - Canon Information Systems, Satoshi Fujitami - Ricoh, Steve
Gebert - IBM, Sue Gleeson - Digital, Charles Gordon - Osicom, Brian
Grimshaw - Apple, Jerry Hadsell - IBM, Richard Hart - Digital, Tom
Hastings - Xerox, Henrik Holst - I-data, Stephen Holmstead, Zhi-Hong
Huang - Zenographics, Scott Isaacson - Novell, Babek Jahromi -
Microsoft, Swen Johnson - Xerox, David Kellerman - Northlake
Software, Robert Kline - TrueSpectra, Charles Kong - Panasonic, Carl
Kugler - IBM, Dave Kuntz - Hewlett-Packard, Takami Kurono - Brother,
Rick Landau - Digital, Scott Lawrence - Agranot Systems, Greg LeClair
- Epson, Dwight Lewis - Lexmark, Harry Lewis - IBM, Tony Liao - Vivid
Image, Roy Lomicka - Digital, Pete Loya - HP, Ray Lutz - Cognisys,
Mike MacKay - Novell, Inc., David Manchala - Xerox, Carl-Uno Manros -
Xerox, Jay Martin - Underscore, Stan McConnell - Xerox, Larry
Masinter - Xerox, Sandra Matts - Hewlett Packard, Peter Michalek -
Shinesoft, Ira McDonald - High North Inc., Mike Moldovan - G3 Nova,
Tetsuya Morita - Ricoh, Yuichi Niwa - Ricoh, Pat Nogay - IBM, Ron
Norton - Printronics, Hugo Parra, Novell, Bob Pentecost - Hewlett-
Packard, Patrick Powell - Astart Technologies, Jeff Rackowitz -
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Intermec, Eric Random - Peerless, Rob Rhoads - Intel, Xavier Riley -
Xerox, Gary Roberts - Ricoh, David Roach - Unisys, Stuart Rowley -
Kyocera, Yuji Sasaki - Japan Computer Industry, Richard Schneider -
Epson, Kris Schoff - HP, Katsuaki Sekiguchi - Canon Information
Systems, Bob Setterbo - Adobe, Gail Songer - Peerless, Hideki Tanaka
- Cannon Information Systems, Devon Taylor - Novell, Inc., Mike
Timperman - Lexmark, Atsushi Uchino - Epson, Shigeru Ueda - Canon,
Bob Von Andel - Allegro Software, William Wagner - NetSilicon/DPI,
Jim Walker - DAZEL, Chris Wellens - Interworking Labs, Trevor Wells -
Hewlett Packard, Craig Whittle - Sharp Labs, Rob Whittle - Novell,
Inc., Jasper Wong - Xionics, Don Wright - Lexmark, Michael Wu -
Heidelberg Digital, Rick Yardumian - Xerox, Michael Yeung - Canon
Information Systems, Lloyd Young - Lexmark, Atsushi Yuki - Kyocera,
Peter Zehler - Xerox, William Zhang- Canon Information Systems, Frank
Zhao - Panasonic, Steve Zilles - Adobe, and Rob Zirnstein - Canon
Information Systems.
Authors' Addresses
Michael Sweet
Apple Inc.
1 Infinite Loop
MS 111-HOMC
Cupertino, CA 95014
US
Email: msweet@apple.com
Ira McDonald
High North, Inc.
PO Box 221
Grand Marais, MI 49839
US
Phone: +1 906-494-2434
Email: blueroofmusic@gmail.com
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