INTERNET-DRAFT                                              Roger deBry
<draft-ietf-ipp-collection-02.txt>
<draft-ietf-ipp-collection-03.txt>            Utah Valley State College
                                                             T. Hastings
                                                       Xerox Corporation
                                                              R. Herriot
                                                       Xerox Corporation
                                                                 K. Ocke
                                                       Xerox Corporation
                                                               P. Zehler
                                                       Xerox Corporation
                                                           March 9,
                                                           June 29, 2000

                   Internet Printing Protocol (IPP):
                   The 'collection' attribute syntax

    Copyright (C) The Internet Society (2000). All Rights Reserved.

Status of this Memo:

This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of [RFC2026].  Internet-Drafts are working
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                                Abstract

   This document specifies an OPTIONAL attribute syntax called
   'collection' for use with the Internet Printing Protocol/1.0
   (IPP) [RFC2565, RFC2566], IPP/1.1 [ipp-mod, ipp-pro], and
   subsequent versions. A 'collection' is a container holding one or
   more named values, which are called "member" attributes.  A
   collection allows data to be grouped like a PostScript dictionary
   or a Java Map.

   There are 4 issues in  This document also specifies the document.

                    [Expires:  September 9, 2000] conformance
   requirements for a definition document that defines a collection
   attribute.

deBry, Hastings, Herriot, Ocke, Zehler  Expires: December 29, 2000  [1]

The full set of IPP documents includes:

  Design Goals for an Internet Printing Protocol [RFC2567]
  Rationale for the Structure and Model and Protocol for the Internet
     Printing Protocol [RFC2568]
  Internet Printing Protocol/1.1: Model and Semantics (this document)
  Internet Printing Protocol/1.1: Encoding and Transport [IPP-PRO]
  Internet Printing Protocol/1.1: Implementer's Guide [IPP-IIG]
  Mapping between LPD and IPP Protocols [RFC2569]

The "Design Goals for an Internet Printing Protocol" document takes a
broad look at distributed printing functionality, and it enumerates
real-life scenarios that help to clarify the features that need to be
included in a printing protocol for the Internet.  It identifies
requirements for three types of users: end users, operators, and
administrators.  It calls out a subset of end user requirements that are
satisfied in IPP/1.0.  A few OPTIONAL operator operations have been
added to IPP/1.1.

The "Rationale for the Structure and Model and Protocol for the Internet
Printing Protocol" document describes IPP from a high level view,
defines a roadmap for the various documents that form the suite of IPP
specification documents, and gives background and rationale for the IETF
working group's major decisions.

The "Internet Printing Protocol/1.1: Encoding and Transport" document is
a formal mapping of the abstract operations and attributes defined in
the model document onto HTTP/1.1 [RFC2616].  It defines the encoding
rules for a new Internet MIME media type called "application/ipp".  This
document also defines the rules for transporting 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.

The "Internet Printing Protocol/1.1: Implementer's Guide" document gives
insight and advice to implementers of IPP clients and IPP objects.  It
is intended to help them understand IPP/1.1 and some of the
considerations that may assist them in the design of their client and/or
IPP object implementations.  For example, a typical order of processing
requests is given, including error checking.  Motivation for some of the
specification decisions is also included.

The "Mapping between LPD and IPP Protocols" document gives some advice
to implementers of gateways between IPP and LPD (Line Printer Daemon)
implementations.

                    [Expires:  September 9, 2000]

                           Table of Contents

1  Problem Statement.................................................4 Statement.................................................5
2  Solution..........................................................4  Solution..........................................................5
3  Definition of a Collection Attribute..............................5 Attribute..............................6
 3.1 Member Attribute Naming Rules..................................5 Information to Include.........................................6
 3.2 Remaining rules for a collection attribute definition..........6
 3.3 Nested Collections.............................................8
 3.4 Collections.............................................9
4  Collection Attributes as Operation Attributes..................9
 3.5 Collections as Job Template Attributes.........................9
 3.6 Collections and Get-Printer-Attributes and Get-Job-Attributes
 operations.........................................................10
4  New Out-of-band value............................................11 Attributes in Operations.................9
 4.1 'none'........................................................11
5 General Rules..................................................9
 4.2 Unsupported Values...............................................12 Values.............................................9
5  Example definition of a collection attribute.....................10
 5.1 media-col (collection)........................................10
   5.1.1media-color (type3 keyword | name(MAX)......................11
   5.1.2media-size (collection).....................................11
 5.2 media-col-default (collection)................................12
 5.3 media-col-ready (1setOf collection)...........................12
 5.4 media-col-supported (1setOf type2 keyword)....................12
6  Sample specification.............................................12  A Second Example Definition Of A Collection Attribute............12
7  Encoding.........................................................13
 7.1 encoding of Additional tags defined for representing a collection (using solution 1a)..................17 attribute
 value..............................................................13
 7.2 Sample Encoding (using solution 1a)...........................19
 7.3 1setOf Collection encoding (using solution 1a)................20
 7.4 Sample 1setOf Collection encoding (using solution 1a).........21 Example encoding: "media-col" (collection)....................14
8  Legacy issues....................................................23 issues....................................................17
9  IANA Considerations..............................................24 Considerations..............................................18
10 Internationalization Considerations..............................24 Considerations..............................18
11 Security Considerations..........................................24 Considerations..........................................18
12 References.......................................................24 References.......................................................18
13 Author's Addresses...............................................25 Addresses...............................................19
14 Appendix A: Encoding Example of a Simple Collection..............20
15 Appendix B: Encoding Example of 1setOf Collection................22
16 Appendix C: Encoding Example of Collection containing 1setOf XXX
attribute............................................................26
17 Appendix D: Full Copyright Statement.............................26

                    [Expires:  September 9, 2000] Statement.............................28

                            Table of Tables

Table 1 - "media-col" member attributes..............................11

Table 2 - "media-size" collection member attributes..................11

Table 3 - Tags defined for encoding the 'collection' attribute syntax13

Table 4 - Overview Encoding of "media-col" collection................15

Table 5 - Example Encoding of "media-col" collection.................15

Table 6 - Overview Encoding of simple collection.....................21

Table 7 - Example Encoding of simple collection......................21

Table 8 - Overview Encoding of 1setOf collection.....................23

Table 9 - Example Encoding of 1setOf collection......................23

Table 10 - Overview Encoding of collection with 1setOf value.........26

Table 11 - Example Encoding of collection with 1setOf value..........26

1  Problem Statement

The IPP Model and Semantics [ipp-mod] supports most of the common data
structures that are available in programming languages. It lacks a
mechanism for grouping several attributes of different types.  The Java
language uses the Map to solve this problem and PostScript has a
dictionary.  The new mechanism for grouping attributes together (called
'collection' mechanism) must allow for optional members and subsequent extension
addition of the collection. new members.

The 'collection' mechanism must be encoded in a manner consistent with
existing 1.0 and 1.1 parsing rules (see [ipp-pro]).  Current 1.0 and 1.1
parsers that don't support collections should the 'collection' mechanism must not confuse
collections or parts of collection they receive with attributes that they do support. other attributes.

2  Solution

The new mechanism is a new IPP attribute syntax called a 'collection'.
As such such, each collection value is a value of an attribute whose
attribute syntax type is defined to be a 'collection'.  Such an
attribute is called a collection attribute.  The name of the collection
attribute serves to identify the collection value in an operation
request or response, as with any attribute value.

The 'collection' attribute syntax is a container holding one or more
named values (i.e., attributes), which are called member attributes.
Each collection attribute definition document lists the mandatory and
optional member attributes of each collection value. A collection value
is similar to an IPP attribute group in a request or a response, such as
the operation attributes group. They both consist of a set of
attributes.

As with any attribute syntax, the document that defines a collection
attribute definition
document specifies whether the attribute is single-value (collection)
or multi-valued (1setOf collection).

The name of each member attribute MUST be unique, but MAY be the same as If the name of a member attribute in another is multi-valued
(1setOf collection) each collection type and/or MAY value MUST be
the same as the name a separate instance of an attribute that is not
a member single definition of a
collection..  The rules for naming collection, i.e. it MUST have the same member
attributes are given in
section 3.1.

Each except for OPTIONAL member attributes. If we view each
collection definition as a separate syntax type, this rule continues the
IPP/1.1 notion that each attribute has a single type or pattern (e.g.
"keyword | name" is a pattern). Without this rule, the supported values
would be more difficult to describe and the mechanism defined in item 4
of section 3.1would not be sufficient.

The name of each member attribute MUST be unique for a collection
attribute, but MAY be the same as the name of a member attribute in
another collection attribute and/or MAY be the same as the name of an
attribute that is not a member of a collection.  The rules for naming
member attributes are given in section 3.1.

Each member attribute can have any attribute syntax type, including
'collection', and can be either single-valued or multi-valued.  The
length of a collection value is not limited. However, the length of each
member attribute MUST NOT exceed the limit of its attribute syntax.

The member attributes in a collection MAY be in any order in a request
or response. When a client sends a collection attribute to the Printer,

                    [Expires:  September 9, 2000]
the order that the Printer stores the member attributes of the
collection value and the order returned in a response MAY be different
from the order sent by the client.

A collection value MUST NOT contains two or more member attributes with
the same attribute name.  Such a collection is mal-formed.  Clients MUST
NOT submit such malformed requests and Printers MUST NOT return such
malformed responses.  If such a malformed request is submitted to a
Printer, the Printer MUST (depending on implementation) either (1)
reject the request with the 'client-error-bad-
request' 'client-error-bad-request' status code (see
section 13.1.4.1)

ISSUE 01:  In attribute groups [ipp-mod] allows a Printer either (1) to
reject a request with duplicate named attributes OR 13.1.4.1), or (2) to choose
exactly one of the attributes as accept the request and use only one to be used.  Should we REQUIRE
the Printer to reject of each
duplicate named attributes in a collection value
as stated above or allow the Printer to choose one member attribute as a
second alternative as we do with attribute groups? attribute..

3  Definition of a Collection Attribute

This section describes the requirements for any collection attribute
definition.

3.1 Member Attribute Naming Rules

Each Information to Include

When a specification document defines an "xxx" collection attribute,
i.e., an attribute whose attribute syntax type is 'collection' or
'1setOf collection'; the definition document MUST have a unique name within include the scope in
which following
aspects of the collection attribute occurs.  If semantics.  Suppose the "xxx" collection
attribute
occurs as a contains N member attributes named  "aaa1", "aaa2", ., "aaaN"
("aaaI" represents any one of a request or response these N member attributes).

  1. The name of the collection attribute group, it MUST be
unique within that group, specified  (e.g.
     "xxx"). The selection of the name "xxx" MUST follow the same rules
     for uniqueness as for attributes of any other attribute.  If a
collection attribute occurs as syntax type (as
     defined by IPP/1.1) unless "xxx" is a member attribute of another collection,
     collection. Then the selection of the collection attribute MUST have a unique name within that collection
value, same as "xxx" MUST follow the
     rules for any other attribute.

Each member attribute uniqueness defined in a item 5a)  of this list.

  2. The collection value attribute syntax MUST have unique name within
that be of type 'collection' or
     '1setOf collection'.

  3. The context of the collection value.  Member attribute names MAY MUST be reused between
different collection attributes.  An example is specified, i.e.,
     whether the "media" attribute
which MAY be used as is an operation attribute, a job template attribute (see [ipp-mod]) and in Job Template
     attribute, a
collection.  All attribute names that are reused MUST have an identical
syntax.  All Job Description attribute, a Printer Description
     attribute, a member attribute names that are reused MUST have of a similar
semantics.  The semantic difference particular collection attribute,
     etc.

  4. An "xxx-supported" attribute MUST be limited to boundary
conditions specified and constraints placed on it has one of
     the reused attributes.  All
attributes that are not reused from elsewhere in following two forms:

     a)"xxx-supported" is a "1setOf collection" which enumerates all of
       the IPP model supported collection values of "xxx". If a collection of
       this form contains a nested collection, it MUST be of the same
       form.

       For example, "media-size-supported" might have
a globally unique name.

Assume the values  {{x-
       dimension:210, y-dimension:297},{x-dimension:297, y-
       dimension:420}} to show that it supports two values of "media
       size": A4 (210x297) and A3 (297x420). It does not support other
       combinations of "x-dimension" and "y-dimension" member
       attributes, such as 210x420 or 297x297 and it does not supported
       non-enumerated values, such as 420x595.

     b)"xxx-supported" is desirable to extend IPP by adding a Job Template
attribute that allows the client to select "1setOf  type2 keyword" which enumerates
       the media by its properties,
e.g., weight, color, size, etc., instead names of all of by name as the "media (type3 member attributes of "xxx": "aaa1",
       "aaa2", ., "aaaN". If a collection of this form contains a
       nested collection, it MAY be of either form. See item 5f) below
       for details on supported values of member attributes.

       For example, "media-col-supported" might have the keyword | name) Job Template attribute in IPP/1.1 (see [ipp-mod]).
       values: "media-size" and "media-color".

  5. The
first rule is that the existing member attributes MUST be defined.  For each member attribute
     the definition document MUST provide the following information:

     a)The member attribute's name (e.g., "aaa") MUST NOT be extended by adding unique within
       the collection being defined and MUST either

       i) reuse the 'collection' attribute syntax to name of another attribute (that is unique
          across the existing "media" attribute.
That would cause too many interoperability problems entire IPP attribute name space) and complicates have the

                    [Expires:  September 9, 2000]

validation same
          syntax and defaulting rules semantics as well.  Instead, a new the reused attribute will
be defined with a suffix (if the condition
          of "-col" (for collection), e.g., "media-col"
(collection). item 4b) above is met). For a second example, suppose it is desirable to extend IPP by allowing
the client to select the media for a member attribute
          definition could reuse the job start sheet.  Again, this
would not be done by adding IPP/1.1 "media" attribute.

       ii)    potentially occur elsewhere in the 'collection' entire IPP attribute syntax to
          name space. (if the
existing "job-sheets" (type2 keyword | name) Job Template attribute.
Instead, condition of item 4a) above is met). For
          example, a new "job-sheet-col" (collection) Job Template member attribute MUST could be introduced.  The member of the "job-sheet-col" "x-dimension" which could
          potentially occur in another collection might be:

     "job-sheet-format" (type3 keyword | name)
     "media" (type3 keyword | name)

if any or as an attribute
          outside of a collection.

       iii)   be unique across the "media-supported" (1setOf (type3 keyword | name)) Printer entire IPP attribute values could be specified for job sheets.  The reason that name space (if
          the
"job-sheet-format" condition of item 4b) above is met). For example, a member
          attribute isn't named simply, "job-sheet", is
because its values only indicate the format, and don't imply any media,
while could be "media-color" which must unique be across
          the "job-sheets" (type2 keyword | name) Job Template entire IPP attribute do
imply a media.  This example illustrates when a name space.

     b)Whether the member attribute can be is REQUIRED or OPTIONAL for the same as another attribute (in this case a Job Template attribute)
and when
       Printer to support

     c)Whether the member attribute MUST have is REQUIRED or OPTIONAL for the
       client to supply in a different name. request

     d)The member attribute's syntax type, which can be any attribute
       syntax, including '1setOf X', 'collection', and '1setOf
       collection'.  If this attribute name reuses the definers name of the "job-sheet-col" (collection) another
       attribute intended
that the System Administrator be allowed to have a different set (case of
media values for job sheets than documents, then the definition document
for item a1 above), it MUST have the "job-sheet-col" collection same
       attribute would have syntax, including cardinality (whether or not 1setOf).

     e)The semantics of the following "aaa" member attributes instead:

     "job-sheet-format" (type3 keyword | name)
     "job-sheet-media" (type3 keyword | name)

Then the supported values would be include in a separate "job-sheet-
media-supported" (1setOf (type3 keyword | name)) Printer attribute.

3.2 Remaining rules for a collection attribute The semantic
       definition

When MUST include a specification document defines an "xxx" collection attribute,
i.e., an attribute whose attribute syntax type is 'collection' description of any constraint or
'1setOf collection';
       boundary conditions the definition document MUST include member attribute places on the following
aspects of
       associated attribute, especially if the attribute semantics.  Suppose reuses the "xxx" collection
       name of another attribute contains an "aaa" (case of item a1 above)

     f)The supported values for the each "aaaI" member attribute.  A simplified example attribute (of
       the member attributes  "aaa1", "aaa2", ., "aaaN") is specified
       by one of two mechanisms.

       i) If "xxx-supported" is a
collection specification "1setOf collection" (see item 4a)
          above), the value for each "aaaI" is given specified in section 6

  1. The name of the collection attribute MUST be specified.  (e.g.
     "xxx")

  2. The each
          collection attribute syntax MUST be value of type 'collection' or
     '1setOf collection'.

  3. The "xxx-supported" in the context of other
          member attributes. That is, "xxx-supported" enumerates all
          supported values of "xxx".

       ii)  If the collection attribute MUST be specified, i.e.,
     whether the attribute value of "xxx-supported" is an operation attribute, a Job Template
     attribute, a Job Description attribute, a Printer Description

                    [Expires:  September 9, 2000]
     attribute, a member "1setOf  type2
          keyword" (see item 4b) above), the supported values of "aaaI"
          are the values specified by either i) the "aaaI-supported"
          attribute or ii) the definition of a particular collection attribute,
     etc.

  4. The member attributes MUST be defined.  For each the member attribute "aaaI"
          within the definition document MUST provide defining the following:

     a)The "xxx" attribute. The values
          of each member attribute's name, "aaa", MUST either (1) reuse the attribute name "aaaI" are specified independently of another attribute if the
          other member attribute
       shares attributes though a Printer is not required to
          support all combinations of supported values.

          For example, "media-col-supported" might have the syntax keyword
          values: "media-size" and semantics with "media-color". Using the other attribute or (2)
       be unique across first method
          for defining supported values (an "aaaI-supported" attribute),
          the entire IPP attribute name space

     b)Whether collection values of "media-col" are combinations of
          values of "media-size-supported" and "media-color-
          supported".If "media-size-supported" has the member attribute is REQUIRED or OPTIONAL for values of
          '210x297' and '297x420' and "media-color-supported" has the
          values of 'white' and 'pink', the Printer to might support

     c)Whether only
          the combinations 'white-210x297', 'pink-210x297'and 'white-
          297x420', and not 'pink-297x420'.

          If a collection contains a member "aaaI" whose syntax type is
          "text", the supported values would probably be defined by the
          definition of "xxx" rather than by the attribute "aaaI-
          supported".

     g)the default value of each "aaaI" member attribute if it is REQUIRED or
       OPTIONAL for the a client to supply in a request

     d)The the "aaa" member attribute's syntax type, which can be any attribute
       syntax, including '1setOf X', 'collection', and '1setOf
       collection'.  If this attribute name is the same as another
       attribute (case of option a-1 above), it MUST have the same
       attribute syntax, including cardinality (1setOf or not).

     e)The semantics of the "aaa" member attribute. The semantic
       definition MUST include a description of any constraint or
       boundary conditions the member attribute places on the
       associated attribute, especially if the attribute is the same as
       another attribute used in a different context (case of option a-
       1 above)

     f)the supported values for the "aaa" member attribute, either
       enumerated explicitly or specified by the values of a referenced
       attribute which may be
       request. The default value is specified by either:

          @ in the attribute's
       definition

          @ a Printer attribute, such as "aaa-supported", which
            contains the explicit values supported. The "aaa-supported"
            attribute is within a Printer attribute document and not in MUST be one of the following:

       i) a collection.
            For example, if fixed default

       ii)  a collection contains the "media" attribute
            and its supported values are specified mechanism by which the "media-
            supported" attribute, the "media-supported" attribute Printer determines default
       iii) an indefinite default that is left to the same Printer implementation.

       iv)  an attribute that the "media" attribute uses.

     g)the Printer uses to determine the default

  6. The default value of "aaa" member attribute "xxx" if it is OPTIONAL
       for a client to does not supply the "aaa" member attribute in a request. it. The
     default value is specified by either:

          @ in the attribute's definition

          @ within
     a document and MUST be one of the following:

     a)a fixed default

     b)a mechanism by which the Printer attribute, such as "aaa-default", determines default

     c)an indefinite default that is left to the implementation

     d)a Printer attribute "xxx-default" which may have is a collection value

                    [Expires:  September 9, 2000]
          @ or an implementation defined algorithm that takes into
            account the values of with the other
       same member attributes of the
            collection value

     h)Depending on the collection as "xxx". Though optional member
       attributes context, it MUST follow may be absent in which case the additional Printer uses the
       defaulting rules specified below for of item 5g) above.

  7. The "xxx-ready (1setOf collection)" attribute if human intervention
     is required to make many of the various contexts.

3.3 supported values available.  For
     example, "media-col" is an attribute which has a "ready" attribute.
     Most attributes do not have a "ready" attribute.

3.2 Nested Collections

A member attribute may have a syntax type of 'collection' or '1setOf
collection'. The following example assumes a "yyy" collection attribute
collection', in which case it is called a member attribute of the preceding "xxx" collection attribute.   The
"yyy" nested collection attribute contains "bbb" member attribute.
The
definition document rules for the a nested collection MUST include:

1.The name of attribute are the collection attribute, e.g., "yyy"

2.The same as for a
collection attribute syntax MUST be as specified in section 3.1.

4  Collection Attributes as Attributes in Operations

4.1 General Rules

A collection value is like any other IPP/1.1 value, except that it is
structured. The rules for attributes with collection values are the same
as for attributes of any other syntax type 'collection' or
  '1setOf collection'

3.The member attributes MUST (see IPP/1.1), be defined.  For each member attribute the
  definition document MUST provide the following:

  a) The member attribute's name, "bbb", MUST either (1) reuse the
     attribute name they in any
group of another attribute if the member a request of a response.

4.2 Unsupported Values

The rules for returning an unsupported collection attribute shares
     the syntax and semantics with are an
extension to the other attribute or (2) be unique
     across current rules:

   1.  If the entire IPP attribute name space

  b) Whether the member collection attribute is REQUIRED or OPTIONAL for unsupported, then the
       Printer to support

  c) Whether returns just the member collection attribute is REQUIRED or OPTIONAL for name with the client
     to supply
       'unsupported' out-of-band value (see the beginning of [ipp-mod]
       section 4.1) in the Unsupported Attributes Group.

   2.  If a request

  d) The collection contains unrecognized, unsupported member attribute's syntax type, which can be any attribute
     syntax, including '1setOf X', 'collection', and '1setOf
     collection'.  If this attribute name is
       attributes and/or conflicting values, the same as another attribute (case of option a-1 above), it MUST have returned in
       the same
     attribute syntax, including cardinality (1setOf or not)

  e) The semantics of Unsupported Group is a collection containing the
       unrecognized, unsupported member attribute. attributes, and/or conflicting
       values. The semantic definition MUST
     include a description unrecognized member attributes have an out-of-band
       value of any constraint or boundary conditions 'unsupported' (see the beginning of [ipp-mod] section
       4.1). The unsupported member attributes and conflicting values
       have their unsupported or conflicting values.

5  Example definition of a collection attribute places on

In some printing environments, it is desirable to allow the associated attribute, especially if client to
select the media by its properties, e.g., weight, color, size, etc.,
instead of by name. In IPP/1.1 (see [ipp-mod]), the "media (type3
keyword | name) Job Template attribute allows selection by name.   It is
tempting to extend the same as another "media" attribute used in a different
     context (case of option a-1 above)

  f)

  g) Depending on syntax to include "collection",
but then existing clients could not understand default or supported
media values that use the collection attributes context, it value. To preserve
interoperability, a new attribute MUST follow the
     additional rules specified below for the various contexts.

                    [Expires:  September 9, 2000]

3.4 Collection Attributes as Operation Attributes BE added, e.g., "media-col
(collection)". The following subsections contain a sample definition documents that define of
a collection attribute for use as
an operation attribute MUST follow these additional rules:

    a)Define simplified "media-col" attribute. The definition follows the rules in which operation requests
section 3.

Note: we picked the collection attribute name "media-col" because the name "media" is
      intended to be used.

    b)Define already
in which operation responses use. Ordinarily the collection attribute is
      intended to be used.

3.5 Collections as Job Template Attributes

The definition documents for collection attributes that are specified to
be Job Template attributes (see [ipp-mod] section 4.2) MUST would have
associated printer attributes with suffixes of "-supported" and "-
default" (or indicate that there is no "-default"), just as for a name like any Job
Template attribute.  Certain Job Template collection attributes also
have an associated Printer attribute with "-ready" (for example, see the
"media-ready"
other attribute and would not end in [ipp-mod]).  Furthermore "col".

The member attributes of
job template attributes are addressed using the same suffix convention.

See also section 3.6 on the interaction of collections and the Get-
Printer-Attributes "media-col" attribute ("media-color (type 3
keyword)" and Get-Jobs-Attributes.

For "media-size (collection)") both follow the following naming rules assume the "xxx" (collection) example from of
item 4a3 of section 3.2 is a job template attribute.

1)There MUST be two associated printer attributes.  The attributes 3, i.e. the names are
  "xxx-supported" and "xxx-default"

2)The "xxx-default" is a collection with a syntax identical to unique across the
  "xxx" specification in section 3.2 .

     @ Each member entire IPP
attribute has the same name as in the "xxx"
       definition.

     @ A Get-Printer-Attributes operation MUST return space. The member attributes of the "xxx-default"
       (collection) Printer "media-size
(collection)" member attribute ("x-dimension (integer(0,MAX))" and all "y-
dimension (integer(0,MAX))") both follow the member attributes.
       Any default values that have been set MUST be returned.  Any
       default values that have not been set MUST return an out naming rules of band
       attribute item 4a2 of 'no-value'.

3.If
section 3, i.e. they potentially occur elsewhere in the definition of IPP attribute
name space.

5.1 media-col (collection)

The "media-col" (collection) attribute augments the IPP/1.1 [ipp-mod]
"media" attribute.  This collection does not mention an "xxx-ready" attribute than it is assumed that one is not defined, though
  implementer's are free enables a client end user
to support an "xxx-ready" as an extension.

4.The collection attribute definition document MUST define an "xxx-
  supported" attribute with either submit a syntax list of '1setOf type2 keyword'
  or '1setOf collection':

                    [Expires:  September 9, 2000]
     @ If media characteristics to the definition uses Printer.  When the '1setOf type2 keyword' attribute
       syntax, it
client specifies media using the "media-col" collection attribute, the
Printer object MUST be match the attribute keyword names of all requested media exactly.  The 'collection'
consists of the following member attributes that the Printer implementation supports in a
       Job Creation operation.  Furthermore, the definition attributes:

                Table 1 - "media-col" member attributes

     Attribute name attribute syntax            request  Printer
                                                          Support

     media-color    type3 keyword | name (MAX)  MAY      MUST
       include corresponding

     media-size     collection                  MUST     MUST

     The definitions of each of for the "aaa-supported" member attributes that correspond to each "aaa" is given in the following

     sub-sections:

     5.1.1     media-color (type3 keyword | name(MAX)

     This member attribute.  Then
       a client can determine attribute identifies the color of the media.  Valid
     values are 'red', 'white' and 'blue'

     The "media-color-supported" (1setOf (type3 keyword | name(MAX)))
     Printer attribute identifies the supported values of each this "media-color"
     member attribute in that the Job Template collection attribute

     @ Printer supports, i.e., the colors
     supported.

     If  the definition uses client omits this member attribute, the '1setOf collection' Printer determines
     the value in an implementation dependent manner.

     5.1.2     media-size (collection)

     This member attribute syntax,
       then identifies the values are size of the supported instances media.  The
     'collection' consists of the "xxx"
       (collection) attribute that a client can supply member attributes shown in a Job
       Creation operation.  It is expected that this second approach
       will be used for small collections whether the number of
       possible Table 2:

          Table 2 - "media-size" collection values is small.  For example, a "media-
       size" (collection) member attributes

          Attribute   attribute in which syntax      request  Printer
          name                                       Support

          x-dimension integer (0:MAX)       MUST     MUST

          y-dimension integer (0:MAX)       MUST     MUST

          The definitions for the member attributes are "x-dimension" (integer) and "y-dimension"
       (integer). The pairs is given in the

          following sub-sections:

          5.1.2.1    x-dimension (integer(0:MAX))

          This attribute identifies the width of integers are just like keywords as far
       as the client localization is concerned, except that if media in inch units
          along the X axis.

          5.1.2.2    y-dimension (integer(0:MAX))

          This attribute identifies the
       client doesn't recognize a size pair height of numbers, it can display the numbers.

  a) media in inch
          units along the Y axis.

          The keywords returned lists all "media-size-supported" (1setOf collection) Printer
          attribute identifies the contained values of this "media-size" member
          attribute
     names.  This example would return that the "aaa" keyword.

  b) Printer supports, i.e., the size
          combinations supported.  The list is recursive and lists all names of the member attributes of
          are the
     contained collections. In section 3.3 same as the printer would return
     "aaa" and "bbb" for collection "xxx"

  c) The encoding convention allows the reconstruction member attributes of the "media-size"
          collection
     structure. The will allow attribute, namely "x-dimension", and "y-dimension",
          since they have the client to reconstruct same attribute syntax and the
     collections. same
          semantics.

5.2 media-col-default (collection)

The client would know that "aaa" is a member of
     collection "xxx".  It can also be derived "media-col-default" Printer attribute specifies the media that collection "bbb" is
     a member of collection "yyy".  See section 7 for more information
     on encoding.

  d) To obtain the supported values for any member attribute a
Printer uses, if any, if the client
     performs a Get-Printer-Attributes operation explicitly requesting omits the member "media-col" and "media".
Job Template attribute name with in the suffix "supported".  If Job Creation operation (and the PDL
doesn't include a media specification).  The member
     attribute is itself a collection rule 4 above applies to attributes are
defined in Table 1.  A Printer MUST support the same member
     attribute.

3.6 Collections and Get-Printer-Attributes and Get-Job-Attributes
    operations

The behavior of collections for "job-description" and "printer-
description" is similar to any other attribute.  Simple attributes
return
for this default collection attribute as it supports for the
corresponding "media-col" Job Template attribute.

5.3 media-col-ready (1setOf collection)

The "media-col-ready" Printer attribute and its value.  For a collection, identifies the media that are
available for use without human intervention, i.e., the media that are
ready to be used without human intervention.  The collection
and its entire value MUST
have all of the member attributes and their values that are returned.  This
includes any containing collections, its member attributes and their
values. supported in Table 1.

5.4 media-col-supported (1setOf type2 keyword)

The same logic applies for the "-default" and "-ready" printer "media-col-supported" Printer attribute associated with a job-template attributes.

                    [Expires:  September 9, 2000]

Whether identifies the Printer applies individual member attributes independently
or takes into account keyword names
of the member attributes supplied by the client supported in the collection, depends on implementation.  Therefore, a client SHOULD
query the Printer's "xxx-default" (collection) "media-col" collection Job
Template attribute, allow the user
to make any changes, and then submit i.e., the entire collection to the
Printer.  Then keyword names of the variability member attributes in defaulting between different
implementations will not cause
Table 1 that the user Printer supports.

6  A Second Example Definition Of A Collection Attribute

In some printing environments, it is desirable to allow the client to get unexpected results.
select the media for the job start sheet.  The semantics reason for "-supported" not adding the
'collection' attribute syntax to the existing "job-sheets" Job Template
attribute is different the same as for "media". Instead, a collection.  Here the
focus new Job Template
attribute is on the introduced, e.g. "job-sheet-col (collection)".

The  member attributes that the collection supports.  This
solution allows for extension of collections "job-sheet-col" attribute ("job-sheets (type 3
keyword)" and allowing "media (type3 keyword | name)")  both follow the member
attributes naming
rules of a collection to vary (i.e. mandatory and optional member
attributes).  Once a client determines what member attributes are
supported in a collection a subsequent request can be constructed item 4a1 of section 3, i.e they reuse existing IPP attributes.
According to
determine the rules, their supported values for come from the member attributes.

Another advantage existing
IPP attributes: "job-sheets-supported" and "media-supported". However,
their default values do not come from "job-sheets-default" and "media-

default", respectively. Rather the definition of "job-sheet-col" says
that "job-sheets (type 3 keyword)" is required and if "media (type3
keyword | name)" is absent, the behavior Printer uses the same media as the rest
of the "-supported" printer
collection job uses.

If "job-sheet-col" attribute is limiting were defined to contain the amount member
attribute "job-sheet-media (type3 keyword | name)" instead of data that is returned on
general queries.  A 'get-printer-attributes' that returns all "media
(type3 keyword | name)", then the
attributes of a printer will not definition would also have to return what may turn out to specify
a "job-sheet-media-supported  (1setOf (type3 keyword | name))" whose
values would be
extensive lists independent of "-supported" attribute values.  An example might be
"media-col" that could "media-supported  (1setOf (type3 keyword
| name))" and would be set separately by a representation System Administrator.

The actual text for media using a collection
that goes beyond the information currently provided by definition of the job-template attribute "media".  The "media-col" could now be used to represent a
job's media, insert sheets and inserted tab sheets.  An IPP Printer
implementation would return the member attributes is left as an
exercise for each of the "-
supported" collections.

4  New Out-of-band reader.

7  Encoding

This section defines the additional encoding tags used according to
[ipp-pro] and gives an example of their use.

7.1 Additional tags defined for representing a collection attribute
    value

4.1 'none'

'none'

The specified Job Template 'collection' attribute in syntax uses the request MUST
          NOT be applied to tags defined in Table 3.

 Table 3 - Tags defined for encoding the job.  Specifically, this 'collection' attribute syntax

     Tag name         Tag      Meaning
                      value
          overrides

     begCollection    0x34     Begin the Printer's "xxx-default" collection attribute value for value.

     endCollection    0x37     End the Job Template attribute, if one exists.

This "out-of-band" collection attribute value.

     memberAttrName   0x4A     The value allows a client to specify "turn-off" is the name of the
                                collection member attribute

When encoding a feature collection attribute "xxx" that is specified by contains an attribute whose value
"aaa" and is a collection. Because a
client specifies a value, not inside another collection, the Printer uses encoding follows these
rules:

1.  The beginning of the client-specified collection is indicated with a value
and not the Printer's default value.

If tag that
    MUST be syntax type 'begCollection' (0x34) with a Printer supports name length and
    Name field that represent the use name of the 'collection' collection attribute syntax for
an
    ("xxx") as with any attribute, followed by a value. The Printer MUST support the use of MAY
    ignore the "out-of-band" value
'none'.

A Printer MUST support and its length of MAY be 0. In the "out-of-band" value 'none' future, however,
    this field MAY contain useful information, such as the value for
an attribute "xxx" if:

                    [Expires:  September 9, 2000]
     @ collection
    name (cf. the definition name of the a C struct).

2.  Each member attribute specifies 'none' MUST be
       supported AND

     @ the definition is encoded as a sequence of the attribute specifies 'none' MAY two or more values
    that appear to be
       supported and it is part of a single multi-valued attribute, i.e.
    1setOf.  The first value of after the 'begCollection' value has the
    attribute "xxx-supported".

5  Unsupported Values

The rules for returning an unsupported collection attribute are an
extension to syntax 'memberAttrName' (0x4A) and its value holds the current rules.

   If
    name of the entire collection first member attribute is unsupported, then (e.g. "aaa"). The second value
    holds the Printer
   returns just first member's attribute value, which can be of any
    attribute syntax, except 'memberAttrName' or 'endCollection'. If the collection
    first member's attribute name with value is multi-valued, the 'unsupported'
   out-of-band third value (see
    holds the beginning second value of [ipp-mod] section 4.1) in the
   Unsupported Attributes Group.

   If a collection contains unrecognized, unsupported member attributes
   and/or conflicting values, first member's value. Otherwise, the
    third value holds the name of second member attribute returned in (e.g. "bbb")
    and its attribute syntax is 'memberAttrName'. In this case, the Unsupported
   Group
    fourth member's value is a collection containing the unrecognized, unsupported member
   attributes, and/or conflicting values. The unrecognized member
   attributes have an out-of-band value of 'unsupported' (see "bbb".

    Note that the
   beginning technique of [ipp-mod] section 4.1). The unsupported member
   attributes and conflicting values have their unsupported or
   conflicting values.

6  Sample specification

This example is encoding a 'collection' as a '1setOf'
    makes it easy for a collection called "media-col".  The "media-col"
attribute is Printer that doesn't support a job template attribute.  This particular
    collection is simplified
and fictitious and is used for illustrative purposes only.

Name: media-col

Syntax: attribute (or the collection

Member Attributes:

     Name: "media-color"

     Syntax: type3 keyword | name

     Mandatory

     Semantics: This attribute identifies syntax at all) to
    simply skip over the color entire collection value.

3.  The end of the media.  Valid
     values are "red" "white" collection is indicated with a value tag that MUST be
    syntax type 'endCollection' (e.g. 0x37) and "blue"

     "media-color-supported" syntax: 1setOf (type2 keyword | name)

     Name: "media-size"

                    [Expires:  September 9, 2000]
     Syntax: collection

     Member Attributes:

          Name: "x-dimension"

          Syntax: integer

          Mandatory

          Semantics: This attribute identifies MAY have a zero name
    length of and a zero value length. In the media in
          inches.  Valid values are any integer though future, this field MAY
    contain useful information,such as the collection name that matches
    the one in practice
          implementation will constrain the range.

          x-supported syntax: rangeOfInteger

          Name: "y-dimension"

          Syntax: integer

          Mandatory

          Semantics: This attribute identifies the width of the media in
          inches.  Valid values are any integer though in practice
          implementation will constrain the range.

          y-supported syntax: rangeOfInteger

     Name: name

     Syntax: See job template attribute "media"

     Optional

     Semantics: See job template attribute "media".  Additional
     restrictions on "media" in this collection are that the "media"
     value must be valid based on the size and color.  When invalid
     names are given based on the size or color, the size or color value
     takes precedence.

     Supported values identical to job template attribute "media-
     supported".

7  Encoding

This section 'begCollection' .

4.  It is still under construction.

We are now down valid to considering two encodings for collections. The goals
of the encoding are:

                    [Expires:  September 9, 2000]
   a) must be simple

   b) a legacy receiver must correctly ignore a collection value and not
incorrectly decode part of have a collection as member attribute that is, itself, a legitimate attribute.

   c) it parses an attributes with collection values as a single unknown
attribute rather than as many unknown attributes.

The two encodings are:

     1) encode attributes within
    attribute, i.e., collections in can be nested within collections.  This
    is represented by the same way as
     attributes outside occurrence of collections, but encode each attribute name
     in a collection so that its name cannot be the same as an member attribute
     name outside that is of a collection. We have considered two solutions for
     encoding
    attribute names.

          a) add syntax type 'begCollection'.  Such a prefix to each collection member attribute name where
          the prefix  is the (outer) attribute's name following
    terminated by a dot
          ("."). Nested collections have extra levels matching 'endCollection'. The name of dotted names.
          For example, the "media-size" such a member
    attribute in "media-col" is
          encoded as "media-col.media-size" and the "x" attribute in
          "media-size" which the immediately preceding value whose syntax type is inside "media"
    'memberAttrName'.

5.  It is encoded as "media-
          col.media-size.x". The outer valid for a collection attribute name is to be multi-valued, i.e.,
    have more than one collection value.  If the "name" of next attribute
    immediately following the begin-collection and end-collection value.

          b) add 'endCollection' has a hyphen suffix to each attribute zero name in length and
    a collection.
          For example, tag of 'begCollection', then the "media-size" collection attribute in "media-col" is
          encoded a multi-
    valued collection, as "media-size-" and the "x" attribute in "media-size"
          which is inside "media" is encoded as "x-". Note the hyphen
          must be a suffix so that the attribute name follows the rules
          for a legal keyword, and the hyphen is chosen because no
          attributes currently end with a hyphen. any attribute. This statement applies to
    collections within collections and collections that are not in
    collections.

7.2 Example encoding: "media-col" (collection)

The empty name is collection specified in section 5is used for the  end-collection value and all but encoding example
shown in Table 5.  The example also shows nested collections, since the first begin-
          collection value.

     2) encode attributes within a collection as a 1setOf values where
     each
"media-size" member attribute whose name is M and whose values are V1 ... Vn are
     encoded as a sequence of n+1 values M, V1, ... Vn. Subsequent
     member attributes continue the value 'collection.  The encoding example
represents a blue 4x6-index cards and takes 216 octets.  The Appendices
contains more complex examples.

Additional examples have been included in the 1setOf values. appendices.

The following are examples overall structure of encodings. In the real encoding, each
"attribute" consists of

    a) a one byte tag

    b) a two byte name length whose value is "n"

    c) "n" bytes of a name

    d) a two bytes value length whose value collection values can be pictorially
represented as:

"media-col" =
     {    "media-color" =  'blue';
          "media-size" =
          {    "x-dimension" = 6;
               "y-dimension" = 4
          }
     },

The full encoding is "v"

    e) "v" bytes of a value

                    [Expires:  September 9, 2000]

To make it easy to read, we show only items c (the name), a (the tag)
and e (the value), in that order.

There are 3 table 4.  A simplified view of the encoding examples for each solution:

   i) media-col with media-color and media-size as member attributes,
and where media-size contains "x" and "y" as collection members.

   ii) media-size-supported with two
looks like this:

         Table 4 - Overview Encoding of "media-col" collection values.

   iii) job-notify with notify-recipients and notify-events which is a
1setOf keyword with 3 values in this example

Solution 1a)

Tag Value               Name                           syntax-type            value
      "media-col"                    begin-collection                    Value

begCollection           media-col               ""
memberAttrName          ""
      "media-col.media-color"                      media-color
keyword                white
      "media-col.media-size"         begin-collection                 ""
      "media-col.media-size.x"       integer                850
      "media-col.media-size.y"       integer                1100
      "media-col.media-size"         end-collection                      blue
memberAttrName          ""
      "media-col"                    end-collection                      media-size
begCollection           ""

      Name                           syntax-type            value
      "media-size-supported"         begin-collection                      ""
      "media-size-supported.x"       integer                850
      "media-size-supported.y"
memberAttrName          ""                      x-dimension
integer                1100
      "media-size-supported"         end-collection                 ""
      "media-size-supported"         begin-collection                      6
memberAttrName          ""
      "media-size-supported.x"       integer                850
      "media-size-supported.y"                      y-dimension
integer                1400
      "media-size-supported"         end-collection                 ""

      Name                           syntax-type            value
      "job-notify"                   begin-collection                      4
endCollection           ""
      "job-notify.notify-recipients" url       "mailto://bill@foo.com"
      "job-notify.notify-events"     keyword             job-completed                      ""                             keyword               job-created
endCollection           ""                             keyword         job-state-changed
      "job-notify"                   end-collection                      ""

Solution 1b)

      Name                           syntax-type            value

          Table 5 - Example Encoding of "media-col"                    begin-collection       ""
      "media-color-"                 keyword                white
      "media-size-"                  begin-collection       ""
      "x-"                           integer                850
      "y-"                           integer                1100

                    [Expires:  September 9, 2000]
      "media-size-"                  end-collection         ""
      ""                             end-collection         ""

      Name                           syntax-type            value
      "media-size-supported"         begin-collection       ""
      "x-"                           integer                850
      "y-"                           integer                1100
      ""                             end-collection         ""
      ""                             begin-collection       ""
      "x-"                           integer                850
      "y-"                           integer               1400
      ""                             end-collection         ""

      Name                           syntax-type            value
      "job-notify"                   begin-collection      ""
      "notify-recipients-"           url      "mailto://bill@foo.com"
      "notify-events-"               keyword          "job-completed"
      ""                             keyword            "job-created"
      ""                             keyword      "job-state-changed"
      "job-notify"                   end-collection        ""

Solution 2)

       Name                          syntax-type collection

Octets           Symbolic       Protocol   comments
                 Value          field

0x34             begCollection  value-tag  beginning of the "media-
                                           col" collection attribute
0x0009                          name-      length of (collection)
                                length     attribute name
media-col        media-col      name       name of (collection)
                                           attribute
0x0000                          value-     defined to be 0 for this
                                length     type
                                           no value
       "media-col"                   begin-collection             ""
       ""                            attribute-name (since value-
                                           length was 0)

0x4A             memberAttrNam  value-tag  starts a new member
                 e                         attribute: "media-color"
       ""

0x0000                          name-      defined to be 0 for this
                                length     type, so part of 1setOf
                                           no name (since name-length
                                           was 0)
0x000B                          value-     length of "media-color"
                                length     keyword                   white
       ""                            attribute-name     "media-size"
       ""                            begin-collection             ""
       ""                            attribute-name              "x"
       ""                            integer                     850
       ""                            attribute-name              "y"
       ""                            integer                    1100
       ""                            end-collection               ""
       ""                            end-collection               ""

      Name                           syntax-type
                                                             st
media-color      media-color    value
      "media-size-supported"         begin-collection             ""
      ""                             attribute-name              "x"
      ""                             integer                     850
      ""                             attribute-name              "y"
      ""                             integer                    1100
      ""                             end-collection               ""
      ""                             begin-collection             ""
      ""                             attribute-name              "x"
      ""                             integer                     850
      ""                             attribute-name              "y"
      ""                             integer                    1400
      ""                             end-collection               ""

      Name                           syntax-type      value

                    [Expires:  September 9, 2000]
      "job-notify"                   begin-collection             ""
      ""                             attribute-name "notify-recipients"
      ""                             url       mailto://bill@foo.com"
      ""                             attribute-name   "notify-events"
      ""                             keyword          "job-completed"
      "" is name of 1   member
                                           attribute

0x44             keyword            "job-created"
      "" type   value-tag  keyword      "job-state-changed"
      ""                             end-collection                ""

Observations:

Solution 1a have identical properties to solution 1b except that the
rules for encoding the type

Octets           Symbolic       Protocol   comments
                 Value          field

0x0000                          name-      0 indicates 1setOf
                                length
                                           no name are more complicated (since name-length
                                           was 0)
0x0004                          value-
                                length
                                                     st
blue             blue           value      value of 1   member
                                           attribute

0x4A             memberAttrNam  value-tag  starts a new member
                 e                         attribute: "media-size"

0x0000                          name-      defined to be 0 for 1a, and the this
                                length     type, so part of 1setOf
                                           no name (since name-length
                                           was 0)
0x000A                          value-     length of
the "media-size"
                                length     keyword
                                                    nd
media-size       media-size     value      Name of 2   member
                                           attribute appears before each end-collection and end-collection in
1a but only before

0x34             begCollection  value-tag  Beginning of the first begin-collection in 1b.

If a "media-
                                           size" collection aware client sends attribute
                                           which is a sub-collection
0x0000                          name-      0 indicates 1setOf
                                length
                                           no name (since name-length
                                           was 0)
0x0000                          value-     collection to attribute names
                                length     have no value
                                           no value (since value-
                                           length was 0)

0x4A             memberAttrNam  value-tag  starts a collection unaware
Printer:

For solutions 1a and 1b)  the Printer sees many attributes in place new member
                 e                         attribute: "x-dimension"

0x0000                          name-      defined to be 0 for this
                                length     type, so part of
the collection and it returns in the Unsupported attribute group, all 1setOf
                                           no name (since name-length
                                           was 0)
0x000B                          value-     length of
the attributes: the "x-dimension"
                                length     keyword
                                                     st
x-dimension      x-dimension    value      name of  1   sub-collection
                                           member attribute outside the collection and each

0x21             integer type   value-tag  attribute
in the collection with it altered name. Thus the unsupported attributes
have names that the client didn't send and they may be in type
0x0000                          name-      0 indicates 1setOf
                                length
                                           no name (since name-length
                                           was 0)
0x0004                          value-     length of an order that
makes it hard integer = 4
                                length

Octets           Symbolic       Protocol   comments
                 Value          field

                                                      st
0x0006                          value      value of  1   sub-
                                           collection member attribute

0x4A             memberAttrNam  value-tag  starts a new member
                 e                         attribute: "y-dimension"

0x0000                          name-      defined to reconstruct the collection. In addition, because the
"end-collection" has the same be 0 for this
                                length     type, so part of 1setOf
                                           no name as (since name-length
                                           was 0)
0x000B                          value-     length of the "y-dimension"
                                length     keyword
                                                     nd
y-dimension      y-dimension    value      name of  2   sub-collection
                                           member attribute for 1a, some
printers will reject the job because the

0x21             integer type   value-tag  attribute appears twice. Also,
1a does not work for a type
0x0000                          name-      0 indicates 1setOf collection because the
                                length
                                           no name (since name-length
                                           was 0)
0x0004                          value-     length of the
attributes appear in front an integer = 4
                                length
                                                      nd
0x0004                          value      value of each begin-collection and thus cannot be
distinguished from two occurrences  2   sub-
                                           collection member attribute

0x37             endCollection  value-tag  end of the same attribute.

For solution 2) the Printer sees the collection as a sub-collection
0x0000                          name-      defined to be 0 for this
                                length     type, so part of 1setOf values where
some values have unknown syntax types
                                           no name (since name-length
                                           was 0)
0x0000                          value-     defined to be 0 for this
                                length     type
                                           no value (since value-
                                           length was 0)
0x37             endCollection  value-tag  end of the 1st collection
                                           value in 1setOf
0x0000                          name-      defined to be 0 for this
                                length     type, so part of 1setOf
                                           no name (since name-length
                                           was 0)
0x0000                          value-     defined to be 0 for this
                                length     type
                                           no value (since value-
                                           length was 0)

8  Legacy issues

IPP 1.x Printers and other values have known syntax
types.  When a collection-unaware printer discovers Clients will gracefully ignore collections and its
member attributes if it doesn't does not understand the collection.  The
begCollection and endCollection elements each look like an attribute

with an attribute syntax that is a collection,  it sees the unknown
attribute as recipient doesn't support and so
should ignore the entire attribute.  The individual member attributes
and their values will look like a 1setOf rather than a collection. It still returns the
attribute-name with the out-of-band value "unsupported" making it easier
for the client.

7.1 encoding values of a collection (using solution 1a)

NOTE:  If we pick another solution to the encoding, this section will
change.

Each collection MUST have a globally unique name.  Each attribute in an
attribute, so that the Printer simply ignores the entire attribute group or a collection MUST have globally unique name.

                    [Expires:  September 9, 2000]

Uniqueness and
all of its values.  Returning unsupported attributes is generated by prepending also simple,
since only the collection name to of the collection attribute using a period, '.' as a separator.

For encoding attributes that have a 'collection' is returned with the
'unsupported' out-of-band value (see section 4.2).

9  IANA Considerations

This attribute syntax, syntax will be registered with IANA after the
attribute's name is REQUIRED WG approves
its specification according to be the first part of each procedures for extension of the member
IPP/1.1 Model and Semantics [ipp-mod].

10 Internationalization Considerations

This attribute name separated syntax by a PERIOD (.) character.  For example, if a
"media-col" (collection) Job Template attribute is added to IPP and
contains a member attribute "color, it  MUST be encoded as a "media-
col.color".  In another example, if the "job-sheets" (collection) Job
Template attribute is added to IPP and reuses itself has no impact on internationalization.
However, the "color" member
attribute, the "color" attribute MUST be encoded as "job-sheets.color".
The "xxx.color" attribute has an identical attribute syntax and similar
semantics.

When encoding a collection attribute "xxx" attributes that contains an attribute
"aaa".  A simplified example of a collection specification is given are subsequently defined for use in
section 6

1.The beginning of the collection is indicated with
a value tag that
  MUST be syntax type 'begincollection' (e.g. 0x34).

2.The length of the collection name (e.g. 0x03)

3.The collection name (e.g. "xxx")

4.A null collection value length (e.g. 0x00)

5.The attributes are encoded may have internationalization considerations, as with may any
attribute, according to [ipp-mod].

11 Security Considerations

This attribute syntax causes no more security concerns than any other attribute.
attribute syntax.  It is valid
  to have a collection a member of a collection.  The modifications
  necessary for encoding member only the attributes of a collection that are as
  follows.

  a) The name of the member attribute MUST be prepended with the
     collection name and a period.

  b) The length of the member subsequently
defined to use this or any other attribute name MUST be adjusted
     appropriately.

6.The end of the collection is indicated with a value tag that MUST be syntax type 'endCollection' (e.g. 0x37).

7.The length that may have security
concerns, depending on the semantics of the collection name (e.g. 0x03)

8.The collection name (e.g. "xxx")

9.A null collection value length (e.g. 0x00)

                    [Expires:  September 9, 2000]

7.2 Sample Encoding (using solution 1a)

NOTE:  If we pick another solution attribute, according to the encoding, this section will
change.

This section defines the encoding of a collection syntax type using
solution 1a.  The collection specified in section 6 is used.  The
encoding is of an implementation that does not support any optional
attributes.  A collection is encoded by using two new tags:

Tag name         Tag      Meaning
                 value

beginCollection  0x34     Begin the named collection.

endCollection    0x37     End the named collection.

 A collection value is encoded as a sequence of attribute values
preceded by a beginCollection attribute
[ipp-mod].

12 References

[ipp-mod]
     Isaacson, S., deBry, R., Hastings, T., Herriot, R., Powell, P.,
     "Internet Printing Protocol/1.1: Model and followed by an endCollection
attribute. The name field of a beginCollection Semantics" draft-ietf-
     ipp-model-v11-06.txt, March 1, 2000.

[ipp-ntfy]
     Isaacson, S., Martin, J., deBry, R., Hastings, T., Shepherd, M.,
     Bergman, R. " Internet Printing Protocol/1.0 & 1.1:  IPP Event
     Notification Specification" draft-ietf-ipp-not-spec-02.txt, work in
     progress, February 2, 2000.

[ipp-pro]
     Herriot, R., Butler, S., Moore, P., Turner, R., "Internet Printing
     Protocol/1.1: Encoding and Transport", draft-ietf-ipp-protocol-v11-
     05.txt, March 1, 2000.

[RFC2565]
     Herriot, R., Butler, S., Moore, P., Tuner, R., "Internet Printing
     Protocol/1.0: Encoding and Transport", RFC 2565, April 1999.

[RFC2566]
     R. deBry, T. Hastings, R. Herriot, S. Isaacson, P. Powell,
     "Internet Printing Protocol/1.0: Model and Semantics", RFC 2566,
     April 1999.

[RFC2567]
     Wright, D., "Design Goals for an endCollection both
contain the name of the collection type, i.e., the keyword name of the
collection attribute, which is a string of ASCII characters. The value
field contains the prefix used Internet Printing Protocol", RFC
     2567, April 1999.

[RFC2568]
     Zilles, S., "Rationale for all subordinate member attributes.
The following example is written in the style of the IPP/1.1 "Encoding Structure and Transport" document [ipp-pro].  The following example is for a media
collection attribute.  The media collection contains 2 member
attributes.  One member is "color" that contains a keyword Model and Protocol for
     the
media's color.  The second attribute is Internet Printing Protocol", RFC 2568, April 1999.

[RFC2569]
     Herriot, R., Hastings, T., Jacobs, N., Martin, J., "Mapping between
     LPD and IPP Protocols", RFC 2569, April 1999.

[RFC2616]
     R. Fielding, J. Gettys, J. Mogul, H. Frystyk, L. Masinter, P.
     Leach, T. Berners-Lee, "Hypertext Transfer Protocol - HTTP/1.1",
     RFC 2616, June 1999.

13 Author's Addresses

     Roger deBry
     Utah Valley State College
     Orem, UT 84058
     Phone: (801) 222-8000
     EMail: debryro@uvsc.edu

     Tom Hastings
     Xerox Corporation
     737 Hawaii St.  ESAE 231
     El Segundo, CA  90245
     Phone: 310-333-6413
     Fax: 310-333-5514
     e-mail: hastings@cp10.es.xerox.com

     Robert Herriot
     Xerox Corp.
     3400 Hill View Ave, Building 1
     Palo Alto, CA 94304
     Phone: 650-813-7696
     Fax:  650-813-6860
     e-mail: robert.herriot@pahv.xerox.com

     Kirk Ocke
     Xerox Corp.
     800 Phillips Rd
     M/S 139-05A
     Webster, NY 14580
     Phone: (716) 442-4832
     EMail: kirk.ocke@usa.xerox.com
     Peter Zehler
     Xerox Corp.
     800 Phillips Rd
     M/S 139-05A
     Webster, NY 14580
     Phone: (716) 265-8755
     EMail: peter.zehler@usa.xerox.com

14 Appendix A: Encoding Example of a Simple Collection

The overall structure of the collection that gives value can be pictorially
represented as:

" media-size " =
     {    "x-dimension" = 6;
          "y-dimension" = 4
     }

A simplified view of the
media's size.  The size encoding would look like this:

            Table 6 - Overview Encoding of simple collection has two

Tag Value               Name                    Value

begCollection           media-size              ""
memberAttrName          ""                      x-dimension
integer attributes "x" and
"y" that gives the media's size in inches                 ""                      6
memberAttrName          ""                      y-dimension
integer                 ""                      4
endCollection           ""                      ""

Note: "" represents a name or value whose length is 0.

            Table 7 - Example Encoding of simple collection

Octets           Symbolic       Protocol   comments
                 Value          field

0x34             beginCollecti             begCollection  value-tag  Beginning  beginning of the "media-
                                           size" collection
                 on
0x0009 attribute
0x000A                          name-      Length      length of collection's name (collection)
                                length
media-col        media-col      Name       Collection's     attribute name
media-size       media-size     name       name of (collection)
                                           attribute
0x0000                          Value-                          value-     defined to be 0 for this
                                length

0x44             keyword type   value-tag  Member attribute     type
0x000F
                                           no value (since value-
                                           length was 0)

0x4A             memberAttrNam  value-tag  starts member attribute:
                 e                         "x-dimension"

0x0000                          name-      Length      defined to be 0 for this
                                length     type, so part of member attribute 1setOf
                                           no name (since name-length
                                           was 0)
0x000B                          value-     length of "x-dimension"
                                length     keyword
                                                     st
x-dimension      x-dimension    value      name
media-col.color  media-         Name       Name of  1   collection
                                           member attribute
                 col.color

0x21             integer type   value-tag  attribute type
0x0000                          name-      0 indicates 1setOf
                                length
                                           no name (since name-length
                                           was 0)
0x0004                          value-     length
blue             blue           Value

0x34             beginCollecti  value-tag  Beginning of the sub-
                 on an integer = 4
                                length
                                                      st
0x0006                          value      value of  1   collection

                    [Expires:  September 9, 2000]
                                           member attribute

Octets           Symbolic       Protocol   comments
                 Value          field

0x000E

0x4A             memberAttrNam  value-tag  starts a new member
                 e                         attribute: "y-dimension"

0x0000                          name-      Length of sub-collection's      defined to be 0 for this
                                length     type, so part of 1setOf
                                           no name
media-col.size   media-         Name       Sub-collection's name
                 col.size
0x0000                          Value- (since name-length
                                           was 0)
0x000B                          value-     length

0x21             integer type   value-tag  Member attribute type
0x0010                          name-      Length of member attribute the "y-dimension"
                                length     keyword
                                                     nd
y-dimension      y-dimension    value      name
media-           media-         Name       Name of  2   collection
                                           member attribute
col.size.x       col.size.x
0x0004                          value-
                                length
0x0006                          Value

0x21             integer type   value-tag  Member  attribute type
0x0007
0x0000                          name-      Length of member attribute      0 indicates 1setOf for
                                length     media-size
                                           no name
media-           media-         Name       Name of member attribute
col.size.y       col.size.y (since name-length
                                           was 0)
0x0004                          value-     length
0x0004                          Value

0x37             endCollection  value-tag  end of the sub-collection
0x0007                          name-      Length of sub-collection's
                                length     name
media-col.size   media-         Name       Sub-collection's name
                 col.size
0x0000                          Value- an integer = 4
                                length
                                                      nd
0x0004                          value      value of  2   collection
                                           member attribute

0x37             endCollection  value-tag  end of the collection
0x0007
0x0000                          name-      Length of collection's name      defined to be 0 for this
                                length
media-col        media-col      Name       Sub-collection's     type, so part of 1setOf
                                           no name (since name-length
                                           was 0)
0x0000                          Value-                          value-     defined to be 0 for this
                                length     type
                                           no value (since value-
                                           length

7.3 was 0)

15 Appendix B: Encoding Example of 1setOf Collection encoding (using solution 1a)

The encoding of a set of collections follows the standard method of
encoding multi-valued IPP attributes.

The "beginCollection" attribute
is coded normally.  The first instance overall structure of the collection follows.  The
"endCollection" MUST appear only once in a collection and MUST follow
the last member of the set of collection.  The member collections of a

                    [Expires:  September 9, 2000]

set of collections are delineated by a specially encoded
"beginCollection" attribute.  The type MUST value can be "beginCollection" (i.e.
0x34).  The length pictorially
represented as:

"media-size-supported" =
     {    "x-dimension" = 6;
          "y-dimension" = 4
     },
     {    "x-dimension" = 3;
          "y-dimension" = 5
     };

A simplified view of the name field MUST be 0x0000.  The name field
MUST be omitted.  The length of the value MUST be the length of the
collection's prefix.  The value MUST be the prefix.

7.4 Sample 1setOf Collection encoding (using solution 1a)

NOTE:  If we pick another solution to the encoding, this section will
change.

This section defines the encoding would look like this:

            Table 8 - Overview Encoding of a collection syntax type using
solution 1a.  The 1setOf collection specified in section 7 is used.  The
difference is that the type

Tag Value               Name                    Value

begCollection           media-size-supported    ""
memberAttrName          ""                      x-dimension
integer                 ""                      6
memberAttrName          ""                      y-dimension
integer                 ""                      4
endCollection           ""                      ""
begCollection           ""                      ""
memberAttrName          ""                      x-dimension
integer                 ""                      3
memberAttrName          ""                      y-dimension
integer                 ""                      5
endCollection           ""                      ""

            Table 9 - Example Encoding of "media-col" is 1setOf collection instead
of collection.  The encoding is of an implementation that does not
support any optional attributes.

Octets           Symbolic       Protocol   comments
                 Value          field

0x34             beginCollecti             begCollection  value-tag  Beginning  beginning of the collection
                 on
0x0009 "media-
                                           size-supported (1setOf
                                           collection" attribute
0x00014                         name-      Length      length of collection's name (collection)
                                length
media-col        media-col      Name       Collection's     attribute name
media-size-      media-size-    name       name of (collection)
supported        supported                 attribute
0x0000                          Value-                          value-     defined to be 0 for this
                                length

0x44             keyword     type
                                           no value (since value-
                                           length was 0)
0x4A             memberAttrNam  value-tag  Member attribute type
0x000F                          name-      Length of  starts member attribute attribute:
                 e                         "x-dimension"
0x0000                          name-      defined to be 0 for this
                                length     name
media-col.color  media-         Name       Name     type, so part of member attribute
                 col.color
0x0004 1setOf
                                           no name (since name-length
                                           was 0)
0x000B                          value-     length
blue             blue           Value

0x34             beginCollecti  value-tag  Beginning of the sub-
                 on                        collection
0x000E                          name-      Length of sub-collection's "x-dimension"
                                length     keyword
                                                     st
x-dimension      x-dimension    value      name
media-col.size   media-         Name       Sub-collection's name
                 col.size
0x0000                          Value-
                                length of  1   collection
                                           member attribute

0x21             integer type   value-tag  Member  attribute type
0x00010
0x0000                          name-      Length of member attribute      0 indicates 1setOf
                                length
                                           no name

                    [Expires:  September 9, 2000] (since name-length
                                           was 0)

Octets           Symbolic       Protocol   comments
                 Value          field

media-           media-         Name       Name of member attribute
col.size.y       col.size.y

0x0004                          value-     length
0x0006                          Value

0x21 of an integer type   value-tag  Member attribute type
0x00010                         name-      Length = 4
                                length
                                                      st
0x0006                          value      value of  1   collection
                                           member attribute
0x4A             memberAttrNam  value-tag  starts member attribute:
                 e                         "y-dimension"
0x0000                          name-      defined to be 0 for this
                                length     name
media-           media-         Name       Name     type, so part of member attribute
col.size.x       col.size.x
0x0004 1setOf
                                           no name (since name-length
                                           was 0)
0x000B                          value-     length
0x0004                          Value

0x37             endCollection  value-tag  end of the sub-collection
0x000E                          name-      Length of sub-collection's "y-dimension"
                                length     keyword
                                                     nd
y-dimension      y-dimension    value      name
media-col.size   media-         Name       Sub-collection's name
                 col.size of  2   collection
                                           member attribute

0x21             integer type   value-tag  attribute type
0x0000                          Value-                          name-      0 indicates 1setOf
                                length

                                           Second
                                           no name (since name-length
                                           was 0)
0x0004                          value-     length of an integer = 4
                                length
                                                      nd
0x0004                          value      value of  2   collection in set

0x34             beginCollecti
                                           member attribute

0x37             endCollection  value-tag  Beginning  end of the collection
                 on
0x0000                          name-      Indicates continuation of      defined to be 0 for this
                                length     set     type, so part of 1setOf
                                           no name (since name-length
                                           was 0)
0x0000                          Value-                          value-     defined to be 0 for this
                                length

0x44             keyword     type
                                           no value (since value-
                                           length was 0)
                                                             nd
0x34             begCollection  value-tag  Member attribute type
0x000F                          name-      Length  beginning of the 2   member
                                           of the 1SetOf "sizes-avail
                                           " collection attribute
0x0000                          name-      Zero length name
media-col.color  media-         Name       Name of indicates
                                length     this is member of previous
                                           attribute
                 col.color
0x0003
                                name       no name (since name-length
                                           was 0)
0x0000                          value-     defined to be 0 for this
                                length     type
                                           no value (since value-
                                           length
red              red            Value

0x34             beginCollecti was 0)
0x4A             memberAttrNam  value-tag  Beginning of the sub-
                 on                        collection
0x000E  starts member attribute:
                 e                         "x-dimension"
0x0000                          name-      Length of sub-collection's      defined to be 0 for this
                                length     name
media-col.size   media-         Name       Sub-collection's name
                 col.size

                    [Expires:  September 9, 2000]     type, so part of 1setOf

Octets           Symbolic       Protocol   comments
                 Value          field

0x0000                          Value-

                                           no name (since name-length
                                           was 0)
0x000B                          value-     length of "x-dimension"
                                length     keyword
                                                     st
x-dimension      x-dimension    value      name of  1   collection
                                           member attribute

0x21             integer type   value-tag  Member  attribute type
0x0010
0x0000                          name-      Length      0 indicates 1setOf
                                length
                                           no name (since name-length
                                           was 0)
0x0004                          value-     length of an integer = 4
                                length
                                                      st
0x0003                          value      value of  1   collection
                                           member attribute

0x4A             memberAttrNam  value-tag  starts member attribute:
                 e                         "y-dimension"
0x0000                          name-      defined to be 0 for this
                                length     type, so part of 1setOf
                                           no name (since name-length
                                           was 0)
0x000B                          value-     length of the "y-dimension"
                                length     keyword
                                                     nd
y-dimension      y-dimension    value      name
media-           media-         Name       Name of  2   collection
                                           member attribute
col.size.y       col.size.y
0x0004                          value-
                                length
0x0006                          Value

0x21             integer type   value-tag  Member  attribute type
0x0010
0x0000                          name-      Length of member attribute      0 indicates 1setOf
                                length
                                           no name
media-           media-         Name       Name of member attribute
col.size.x       col.size.x (since name-length
                                           was 0)
0x0004                          value-     length
0x0004                          Value

0x37             endCollection  value-tag  end of the sub-collection
0x000E                          name-      Length of sub-collection's
                                length     name
media-col.size   media-         Name       Sub-collection's name
                 col.size
0x0000                          Value- an integer = 4
                                length
                                                      nd
0x0005                          value      value of  2   collection
                                           member attribute

0x37             endCollection  value-tag  end of the set of
                                           collections
0x0009 1setOf
                                           collection value
0x0000                          name-      Length      defined to be 0 for this
                                length     type, so part of collection's name
                                length
media-col        media-col      Name       collection's 1setOf
                                           no name (since name-length
                                           was 0)
0x0000                          Value-     Length of collection's                          value-     defined to be 0 for this
                                length     prefix

8  Legacy issues

IPP 1.x Printers and Clients will gracefully ignore collections and its
member attributes if it does not understand the collection.  The
begCollection and endCollection elements each look like an attribute
with an     type
                                           no value (since value-
                                           length was 0)

16 Appendix C: Encoding Example of Collection containing 1setOf XXX
   attribute syntax that the recipient doesn't support and so
should ignore the entire attribute.

The individual member attributes
will look like ordinary attributes, but since they each are encoded with

                    [Expires:  September 9, 2000]

a unique name that can't be overall structure of the same as a top level attribute, each collection value can be pictorially
represented as:

"wagons" =
     {    "colors" = red, blue;
          "sizes" = 4, 6, 8
     }

A simplified view of the member attributes will also encoding would look like attributes that the recipient
doesn't support and so should ignore.

9  IANA Considerations

This attribute syntax will be registered with IANA after the WG approves
its specification according to the procedures for extension this:

      Table 10 - Overview Encoding of the
IPP/1.1 Model and Semantics [ipp-mod].

ISSUE 04 collection with 1setOf value

Tag Value               Name                    Value

begCollection           wagons                  ""
memberAttrName          ""                      colors
keyword                 ""                      red
keyword                 ""                      blue
memberAttrName          ""                      sizes
integer                 ""                      4
integer                 ""                      6
integer                 ""                      8
endCollection           ""                      ""

      Table 11 - Since this is intended to be a standards track document, do
we also register Example Encoding of collection with 1setOf value

Octets           Symbolic       Protocol   comments
                 Value          field

0x34             begCollection  value-tag  beginning of the "wagons"
                                           collection attribute syntax with IANA?

10 Internationalization Considerations

This
0x0005                          name-      length of (collection)
                                length     attribute syntax by itself has no impact on internationalization.
However, the member attributes that are subsequently name
wagons           wagons         name       name of (collection)
                                           attribute
0x0000                          value-     defined to be 0 for use in
a collection may have internationalization considerations, as may any
attribute, according this
                                length     type
                                           no value (since value-
                                           length was 0)

0x4A             memberAttrNam  value-tag  starts a new member
                 e                         attribute: "colors"

0x0000                          name-      defined to [ipp-mod].

11 Security Considerations

This be 0 for this
                                length     type, so part of 1setOf
                                           no name (since name-length
                                           was 0)
0x0006                          value-     length of "colors" keyword
                                length

Octets           Symbolic       Protocol   comments
                 Value          field

                                                             st
colors           colosr         value      value is name of 1   member
                                           attribute syntax causes

0x44             keyword type   value-tag  keyword type

0x0000                          name-      0 indicates 1setOf wagons
                                length
                                           no more security concerns than any other name (since name-length
                                           was 0)
0x0004                          value-
                                length
                                                     st
blue             blue           value      value of 1   member
                                           attribute syntax.  It is only the attributes that are subsequently

0x44             keyword type   value-tag  keyword type

0x0000                          name-      0 indicates 1setOf wagons
                                length
                                           no name (since name-length
                                           was 0)
0x0003                          value-
                                length
                                                     st
red              red            value      value of 1   member
                                           attribute

0x4A             memberAttrNam  value-tag  starts a new member
                 e                         attribute: "sizes"

0x0000                          name-      defined to use be 0 for this or any other
                                length     type, so part of 1setOf
                                           no name (since name-length
                                           was 0)
0x0005                          value-     length of "length-avail"
                                length     keyword
                                                    nd
sizes            sizes          value      Name of 2   member
                                           attribute syntax that may have security
concerns, depending on the semantics

0x21             integer type   value-tag  attribute type
0x0000                          name-      0 indicates 1setOf wagons
                                length
                                           no name (since name-length
                                           was 0)
0x0004                          value-     length of an integer = 4
                                length
                                            st
0x0004                          value      1   value for 1SetOf
                                           integer attribute

0x21             integer type   value-tag  attribute type
0x0000                          name-      0 indicates 1setOf
                                length

Octets           Symbolic       Protocol   comments
                 Value          field

                                           no name (since name-length
                                           was 0)
0x0004                          value-     length of an integer = 4
                                length
                                            nd
0x0006                          value      2   value for 1SetOf
                                           integer attribute

0x21             integer type   value-tag  attribute type
0x0000                          name-      0 indicates 1setOf
                                length
                                           no name (since name-length
                                           was 0)
0x0004                          value-     length of an integer = 4
                                length
                                            rd
0x0008                          value      3    value for 1SetOf
                                           integer attribute

0x37             endCollection  value-tag  end of the attribute, according collection
0x0000                          name-      defined to
[ipp-mod].

12 References

[ipp-mod]
     Isaacson, S., deBry, R., Hastings, T., Herriot, R., Powell, P.,
     "Internet Printing Protocol/1.1: Model and Semantics" draft-ietf-
     ipp-model-v11-06.txt, March 1, 2000.

[ipp-ntfy]
     Isaacson, S., Martin, J., deBry, R., Hastings, T., Shepherd, M.,
     Bergman, R. " Internet Printing Protocol/1.0 & 1.1:  IPP Event
     Notification Specification" draft-ietf-ipp-not-spec-02.txt, work in
     progress, February 2, 2000.

[ipp-pro]
     Herriot, R., Butler, S., Moore, P., Turner, R., "Internet Printing
     Protocol/1.1: Encoding and Transport", draft-ietf-ipp-protocol-v11-
     05.txt, March 1, 2000.

[RFC2565]
     Herriot, R., Butler, S., Moore, P., Tuner, R., "Internet Printing
     Protocol/1.0: Encoding and Transport", RFC 2565, April 1999.

                    [Expires:  September 9, 2000]

[RFC2566]
     R. deBry, T. Hastings, R. Herriot, S. Isaacson, P. Powell,
     "Internet Printing Protocol/1.0: Model and Semantics", RFC 2566,
     April 1999.

[RFC2567]
     Wright, D., "Design Goals for an Internet Printing Protocol", RFC
     2567, April 1999.

[RFC2568]
     Zilles, S., "Rationale be 0 for the Structure and Model and Protocol this
                                length     type, so part of 1setOf
                                           no name (since name-length
                                           was 0)
0x0000                          value-     defined to be 0 for
     the Internet Printing Protocol", RFC 2568, April 1999.

[RFC2569]
     Herriot, R., Hastings, T., Jacobs, N., Martin, J., "Mapping between
     LPD and IPP Protocols", RFC 2569, April 1999.

[RFC2616]
     R. Fielding, J. Gettys, J. Mogul, H. Frystyk, L. Masinter, P.
     Leach, T. Berners-Lee, "Hypertext Transfer Protocol - HTTP/1.1",
     RFC 2616, June 1999.

13 Author's Addresses

     Roger deBry
     Utah Valley State College
     Orem, UT 84058
     Phone: (801) 222-8000
     EMail: debryro@uvsc.edu

     Tom Hastings
     Xerox Corporation
     737 Hawaii St.  ESAE 231
     El Segundo, CA  90245
     Phone: 310-333-6413
     Fax: 310-333-5514
     e-mail: hastings@cp10.es.xerox.com

     Robert Herriot
     Xerox Corp.
     3400 Hill View Ave, Building 1
     Palo Alto, CA 94304
     Phone: 650-813-7696
     Fax:  650-813-6860
     e-mail: robert.herriot@pahv.xerox.com

     Kirk Ocke
     Xerox Corp.
     800 Phillips Rd
     M/S 139-05A
     Webster, NY 14580

                    [Expires:  September 9, 2000]
     Phone: (716) 442-4832
     EMail: kirk.ocke@usa.xerox.com

     Peter Zehler
     Xerox Corp.
     800 Phillips Rd
     M/S 139-05A
     Webster, NY 14580
     Phone: (716) 265-8755
     EMail: peter.zehler@usa.xerox.com

14 this
                                length     type
                                           no value (since value-
                                           length was 0)

17 Appendix A: D: Full Copyright Statement

Copyright (C) The Internet Society (1998,1999,2000). All Rights Reserved

This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it or
assist in its implementation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are included
on all such copies and derivative works.  However, this document itself
may not be modified in any way, such as by removing the copyright notice
or references to the Internet Society or other Internet organizations,
except as needed for the purpose of developing Internet standards in
which case the procedures for copyrights defined in the Internet
Standards process must be followed, or as required to translate it into
languages other than English.

The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.

This document and the information contained herein is provided on an "AS
IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK
FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT
LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT
INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR PURPOSE.

                    [Expires:  September 9, 2000]