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Versions: 00 01 02 03 04 05 rfc2569                                     
INTERNET-DRAFT                                   Robert Herriot (editor)
                                                  Sun Microsystems, Inc.
draft-ietf-ipp-lpd-ipp-map-04.txt                           Tom Hastings
                                                       Xerox Corporation
                                                             Norm Jacobs
                                                  Sun Microsystems, Inc.
                                                              Jay Martin
                                                        Underscore, Inc.
                                                           June 30, 1998

                 Mapping between LPD and IPP Protocols


Status of this Memo

This document is an Internet-Draft.  Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas, and
its working groups.  Note that other groups may also distribute working
documents as Internet-Drafts.

Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time.  It is inappropriate to use Internet-Drafts as reference material
or to cite them other than as "work in progress."

To learn the current status of any Internet-Draft, please check the
"1id-abstracts.txt" listing contained in the Internet-Drafts Shadow
Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe),
munnari.oz.au (Pacific Rim), ftp.ietf.org (US East Coast), or
ftp.isi.edu (US West Coast).

Copyright Notice

Copyright (C)The Internet Society (1997). All Rights Reserved.

Abstract

This document is one of a set of documents, which together describe all
aspects of a new Internet Printing Protocol (IPP). IPP is an application
level protocol that can be used for distributed printing using Internet
tools and technologies. The protocol is heavily influenced by the
printing model introduced in the Document Printing Application (DPA)
[ISO10175] standard. Although DPA specifies both end user and
administrative features, IPP version 1.0 (IPP/1.0) focuses only on end
user functionality.

The full set of IPP documents includes:

   Design Goals for an Internet Printing Protocol [ipp-req]
   (informational)
   Rationale for the Structure and Model and Protocol for the Internet
   Printing Protocol [ipp-rat] (informational)
   Internet Printing Protocol/1.0: Model and Semantics [ipp mod]
   Internet Printing Protocol/1.0: Encoding and Transport [ipp-pro]
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   Mapping between LPD and IPP Protocols (this document) (informational)

The design goals document, "Design Goals for an Internet Printing
Protocol", takes a broad look at distributed printing functionality, and
it enumerates real-life scenarios that help to clarify the features that
need to be included in a printing protocol for the Internet. It
identifies requirements for three types of users: end users, operators,
and administrators. The design goals document calls out a subset of end
user requirements that are satisfied in IPP/1.0. Operator and
administrator requirements are out of scope for version 1.0. The
rationale document, "Rationale for the Structure and Model and Protocol
for the Internet Printing Protocol", describes IPP from a high level
view, defines a roadmap for the various documents that form the suite of
IPP specifications, and gives background and rationale for the IETF
working group's major decisions. The document, "Internet Printing
Protocol/1.0: Model and Semantics", describes a simplified model with
abstract objects, their attributes, and their operations. The model
introduces a Printer and a Job. The Job supports multiple documents per
Job. The model document also addresses how security,
internationalization, and directory issues are addressed. The protocol
specification, "Internet Printing Protocol/1.0: Encoding and Transport",
is a formal mapping of the abstract operations and attributes defined in
the model document onto HTTP/1.1. The protocol specification defines the
encoding rules for a new Internet media type called "application/ipp".

The "Mapping between LPD and IPP Protocols" gives some advice to
implementors of gateways between IPP and LPD (Line Printer Daemon)
implementations. It specifies the mapping between (1) the commands and
operands of the "Line Printer Daemon (LPD) Protocol" specified in RFC
1179 and (2) the operations and parameters of the Internet Printing
Protocol (IPP).  One of the purposes of this document is to compare the
functionality of the two protocols.  Another purpose is to facilitate
implementation of gateways between LPD and IPP. This document also
provides an example,  which gives additional insight into IPP

WARNING:  RFC 1179 was not on standards track.  While RFC 1179 was
intended to record existing practice, it fell short in some areas.
However, this specification maps between (1) the actual current practice
of RFC 1179 and (2) IPP.  This document does not attempt to map the
numerous divergent extensions to the LPD protocol that have been made by
many implementers.













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                           TABLE OF CONTENTS

1. Introduction .......................................................4
2. Terminology ........................................................4
3. Mapping from LPD Commands to IPP Operations ........................5
 3.1 Print any waiting jobs............................................5
 3.2 Receive a printer job.............................................5
   3.2.1  Abort job....................................................6
   3.2.2  Receive control file.........................................7
   3.2.3  Receive data file............................................7
 3.3 Send queue state (short)..........................................7
 3.4 Send queue state (long)...........................................9
 3.5 Remove jobs......................................................10
4. Mapping of LPD Control File Lines to IPP Parameters ...............11
 4.1 Required Job Functions...........................................12
 4.2 Optional Job Functions...........................................12
 4.3 Required Document Functions......................................13
 4.4 Recommended Document Functions...................................14
5. Mapping from IPP operations to LPD commands .......................14
 5.1 Print-Job........................................................15
 5.2 Print-URI........................................................16
 5.3 Validate-Job.....................................................16
 5.4 Create-Job.......................................................16
 5.5 Send-Document....................................................16
 5.6 Send-URI.........................................................17
 5.7 Cancel-Job.......................................................17
 5.8 Get-Printer-Attributes...........................................17
 5.9 Get-Job-Attributes...............................................17
 5.10 Get-Jobs .......................................................18
6. Mapping of IPP Parameters to LPD Control File Lines ...............18
 6.1 Required Job Functions...........................................19
 6.2 Optional Job Functions...........................................19
 6.3 Required Document Functions......................................20
7. Security Considerations ...........................................21
8. References ........................................................21
9. Author's Addresses ................................................21
10.Appendix A: ABNF Syntax for response of Send-queue-state (short) ..22
11.Appendix B: ABNF Syntax for response of Send-queue-state (long) ...22
12.Appendix C: Unsupported LPD functions .............................23
13.Appendix D: Full Copyright Statement ..............................24













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               Mapping between the LPD and IPP Protocols


1. Introduction

The reader of this specification is expected to be familiar with the IPP
Model and Semantics specification [ipp-mod], the IPP Encoding and
Transport [ipp-pro], and the Line Printer Daemon (LPD) protocol
specification [rfc1179] as described in RFC 1179.

RFC 1179 was written in 1990 in an attempt to document existing LPD
protocol implementations.  Since then, a number of undocumented
extensions have been made by vendors to support functionality specific
to their printing solutions.  All of these extensions consist of
additional control file commands.  This document does not address any of
these vendor extensions.  Rather it addresses existing practice within
the context of the features described by RFC 1179.  Deviations of
existing practice from RFC 1179 are so indicated.

Other LPD control file commands in RFC 1179 are obsolete. They are
intended to work on "text" only formats and are inappropriate for many
contemporary document formats that completely specify each page. This
document does not address the support of these obsolete features.

In the area of document formats, also known as page description
languages (PDL), RFC 1179 defines a fixed set with no capability for
extension.  Consequently, some new PDL's are not supported, and some of
those that are supported are sufficiently unimportant now that they have
not been registered for use with the Printer MIB[rfc1759] and IPP[ipp-
mod] [ipp-pro], though they could be registered if desired.  See the
Printer MIB specification [rfc1759] and/or the IPP Model specification
[ipp-mod] for instructions for registration of document-formats with
IANA.  IANA lists the registered document-formats as "printer
languages".

This document addresses the protocol mapping for both directions:
mapping of the LPD protocol to the IPP protocol and mapping of the IPP
protocol to the LPD protocol. The former is called the "LPD-to-IPP
mapper" and the latter is called the "IPP-to-LPD mapper".

This document is an informational document that is not on the standards
track.  It is intended to help implementors of gateways between IPP and
LPD.  It also provides an example, which gives additional insight into
IPP.


2. Terminology

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

RFC 1179 uses the word "command" in two contexts: for over-the-wire
operations and for command file functions. This document uses the word
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"command" for the former and the phrase "functions" for the latter. The
syntax of the LPD commands is given using ABNF [abnf].

The following tokens are used in order to make the syntax more readable:

    LF stands for %x0A (linefeed)
    SP stands for %x20.  (space)
    DIGIT stands for %x30-39 ("0" to "9")

3. Mapping from LPD Commands to IPP Operations

This section describes the mapping from LPD commands  to IPP operations.
Each of the following sub-sections appear as sub-sections of section 5
of RFC 1179.

The following table summarizes the IPP operation that the mapper uses
when it receives an LPD command. Each section below gives more detail.

LPD command                IPP operation

print-any-waiting-jobs     ignore

receive-a-printer-job      Print-Job or Create-Job/Send-Document

send queue state  (short   Get-Printer-Attributesand Get-Jobs
or long)

remove-jobs                Cancel-Job


3.1 Print any waiting jobs

Command syntax:

  print-waiting-jobs = %x01 printer-name LF

This command causes the LPD daemon check its queue and print any waiting
jobs. An IPP printer handles waiting jobs without such a nudge.

If the  mapper receives this LPD command, it MUSTMUST ignore it and send
no IPP operation.


3.2 Receive a printer job

Command syntax:

  receive-job = %x02 printer-name LF

The control file and data files mentioned in the following paragraphs
are received via LPD sub-commands that follow this command. Their
mapping to IPP commands and attributes is described later in this
section.

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The mapper maps the 'Receive a printer job' command to either:

  .  the Print-Job operation which includes a single data file or
  .  the  Create-Job  operation   followed  by  one   Send-Document
     operation for each data file.

If the IPP printer supports both Create-Job and Send-Document, and if a
job consists of:

  .  a single  data  file,  the mapper  SHOULD  use  the  Print-Job
     operation,  but  MAY  use  the  Create-Job  and  Send-Document
     operations.
  .  more than  one  data  file, the  mapper  MUST  use  Create-Job
     followed by one Send-Document for each received LPD data file.

If the IPP printer does not support both Create-Job and Send-Document,
and if a job consists of:

  .  a  single  data  file,  the  mapper  MUST  use  the   PrintJob
     operation.
  .  more than one data file, the mapper MUST submit each  received
     LPD data  file  as  a separate  Print-Job  operation  (thereby
     converting a single LPD job into multiple IPP jobs).

If the mapper uses Create-Job and Send-Document, it MUST send the
Create-Job operation before it sends any Send-Document operations
whether the LPD control file, which supplies attributes for Create-Job,
arrives before or after all LPD data files.

NOTE:  This specification does not specify how the mapper maps: the LPD
Printer-name operand to the IPP "printer-uri" parameter.

The following 3 sub-sections gives further details about the mapping
from  LPD receive-a-printer-job sub-commands.  Each of the following
sub-sections appear as sub-sections of section 6 of RFC 1179.


3.2.1 Abort job

Sub-command syntax:

  abort-job = %x1 LF

This sub-command of receive-a-printer-job is intended to abort any job
transfer in process.

If the mapper receives this sub-command, it MUST cancel the job that it
is in the process of transmitting.

If the mapper is in the process of sending a Print-Job or Create-Job
operation, it terminates the job either by closing the connection, or
performing the Cancel-Job operation with the job-uri that it received
from the Print-Job or Create-Job operation.

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NOTE: This sub-command is implied if at any time the connection between
the LPD client and server is terminated before an entire print job has
been transferred via an LPD Receive-a-printer-job request.


3.2.2 Receive control file

Sub-command syntax:

  receive-control-file = %x2 number-of-bytes SP name-of-control-file LF
  number-of-bytes = 1*DIGIT
  name-of-control-file = "cfA" job-number client-host-name
                          ; e.g. "cfA123woden"
  job-number = 3DIGIT
  client-host-name = <a host name>

This sub-command is roughly equivalent to the IPP Create-Job operation.

The mapper MUST use the contents of the received LPD control file to
create IPP parameter and attribute values to transmit with the Print-Job
or Create-Job operation.


3.2.3 Receive data file

Sub-command syntax:  %x3 number-of-bytes-in-data-file Name-of-data-file

  receive-data-file = %x03 number-of-bytes SP name-of-data-file LF
  number-of-bytes = 1*DIGIT
  name-of-data-file = "df" letter job-number client-host-name
              ; e.g. "dfA123woden for the first file
  letter = %x41-5A /  %x61-7A    ;  "A" to "Z", "a" to "z"
                                 ;  first file is "A",
                                 ; second "B", and  52nd file is "z"
  job-number = 3DIGIT
  client-host-name = <a host name>

This sub-command is roughly equivalent to the IPP Send-Document
operation.

The mapper MUST use the contents of the received LPD data file as the
data to transmit with the IPP Print-Job or Send-Document operation.

Although  RFC-1179 alludes to a method for passing an unspecified
length data file by using an octet-count of zero, no implementations
support this feature.. The mapper MUST reject a job that has a value of
0 in the number-of-bytes field.


3.3 Send queue state (short)

Command syntax:

  send-queue-short  = %x03 printer-name *(SP(user-name / job-number)) LF
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The mapper's response to this command includes information about the
printer and its jobs. RFC 1179 specifies neither the information nor the
format of its response. This document requires the mapper to follow
existing practice as specified in this document.

The mapper MUST produce a response in the following format which
consists of a printer-status line optionally followed by a heading line,
and a list of jobs. This format is defined by examples below. Appendix A
contains the ABNF syntax.

For an printer with no jobs, the response starts in column 1 and is:

no entries

For a printer with jobs, an example of the response is:

pinetree is ready and printing
Rank   Owner      Job          Files             Total Size
active fred       123          stuff             1204 bytes
1st    smith      124          resume, foo       34576 bytes
2nd    fred       125          more              99 bytes
3rd    mary       126          mydoc             378 bytes
4th    jones      127          statistics.ps     4567 bytes
5th    fred       128          data.txt          9 bytes

The column numbers of above headings and job entries are:

|      |          |            |                 |
01     08         19           35                63

The mapper MUST produce each field above from the following IPP
attribute:

   LPD field IPP attribute           special conversion details

   printer-  printer-state and       For a printer-state of idle or
   status    printer-state-reasons   processing, the mapper MUST use
                                     the formats above.  For stopped,
                                     the mapper MUST use printer-state-
                                     reasons to produce an unspecified
                                     format for the error.

   rank      number-of-              the mapper MUST the format above
             intervening-jobs

   owner     job-originating-user-   unspecified conversion; job-
             name                    originating-user-name may be the
                                     mapper's user-name

   job       job-id                  the mapper MUST use the job-id

   files     document-name           the mapper MUST create a comma
                                     separated list of the document-
                                     names and then truncate this list
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   LPD field IPP attribute           special conversion details

                                     to the first 24 characters

   total-    job-k-                  the mapper MUST multiple the value
   size      octets*copies*1024      of job-k-octets by 1024 and by the
                                     value of the "copies" attribute.



A mapper SHOULD use the job attribute number-of-intervening-jobs rather
than the job's position in a list of jobs to determine `rank' because a
Printer may omit jobs that it wants to keep secret. If a printer doesn't
support the job attribute number-of-intervening-jobs, a mapper MAY use
the job's position.

Note: a Printer may set the value of job-originating-user-name to the
authenticated user or to the value of "requesting-user-name", depending
on the implementation and configuration. For a gateway, the
authenticated user is the user-id of the gateway, but the "requesting-
user-name" may contain the name of the user who is the gateway's client.

In order to obtain the information specified above, The LPD-to-IPP
mapper MUST use the Get-Printer-Attributes operation to get printer-
status and SHOULD use the Get-Jobs operation to get information about
all of the jobs. If the LPD command contains job-numbers or user-names,
the mapper MAY handle the filtering of the response. If the LPD command
contains job-numbers but no user-names, the mapper MAY use Get-Job-
Attributes on each converted job-number rather than Get-Jobs. If the LPD
command contains a single user-name but no job-numbers, the mapper MAY
use Get-Jobs with the my-jobs option if the server supports this option
and if the server allows the client to be a proxy for the LPD user.

NOTE:  This specification does not define how the mapper maps the LPD
Printer-name operand to the IPP "printer-uri" parameter.


3.4 Send queue state (long)

Command syntax:

  send-queue-long = %x04 printer-name *(SP(user-name / job-number)) LF

The mapper's response to this command includes information about the
printer and its jobs. RFC 1179 specifies neither the information nor the
format of its response. This document requires the mapper to follow
existing practice as specified in this document.

The mapper MUST produce a response in the following format which
consists of a printer-status line optionally followed a list of jobs,
where each job consists of a blank line, a description line, and one
line for each file. The description line contains the user-name, rank,
job-number and host. This format is defined by examples below. Appendix
B contain the ABNF syntax.
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For an printer with no jobs the response is:

no entries

For a printer with jobs, an example of the response is:

pinetree is ready and printing

fred: active                        [job 123 tiger]
        2 copies of stuff           602 bytes

smith: 1st                          [job 124 snail]
        2 copies of resume          7088 bytes
        2 copies of foo             10200 bytes

fred: 2nd                           [job 125 tiger]
        more                        99 bytes

The column numbers of above headings and job entries are:

|       |                           |
01      09                          41

Although the format of the long form is different from the format of the
short form, their fields are identical except for a) the copies and host
fields which are only in the long form, and b)  the "size" field
contains the single copy size of each file.  Thus the sum of the file
sizes in the "size" field  times the value of the "copies" field
produces the value for the "Total Size" field in the short form. For
fields other than the host and copies fields, see the preceding section.
For the host field see the table below.

   LPD field IPP attribute         special conversion details

   host                            unspecified conversion; job-
                                   originating-host may be the
                                   mapper's host

   copies    copies                the mapper MUST assume the value
                                   of copies precedes the string
                                   "copies of "; otherwise, the
                                   value of copies is 1.



NOTE:  This specification does not define how the mapper maps the LPD
Printer-name operand to the IPP printer-uri parameter.


3.5 Remove jobs

Command syntax:


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  remove-jobs = %x05 printer-name SP agent
                      *(SP(user-name / job-number)) LF

The agent operand is the user-name of the user initiating the remove-
jobs command. The special user-name 'root' indicates a privileged user
who can remove jobs whose user-name differs from the agent..

The mapper MUST issue one Cancel-Job operation for each job referenced
by the remove-jobs command. Each job-number in the remove-jobs command
references a single job. Each user-name in the remove-jobs command
implicitly references all jobs owned by the specified user. The active
job is implicitly referenced when the remove-jobs command contains
neither job-numbers nor user-names. The mapper MAY use Get-Jobs to
determine the job-uri of implicitly referenced jobs.

The mapper MUST not use the agent name of `root' when end-users cancel
their own jobs.  Violation of this rule creates a potential security
violation, and it may cause the printer to issue a notification that
misleads a user into thinking that some other person canceled the job.

If the agent of a remove-jobs command for a job J is the same as the
user name specified with the `P' function in the control file for job J,
then the mapper MUST ensure that the caller of the Cancel-Job command
for job J is the same as  job-originating-user for job J.

Note: This requirement means that a mapper must be consistent in who the
receiver perceives as the caller of IPP operations. The mapper either
acts as itself or acts on behalf of another user. The latter is
preferable if it is possible. This consistency is necessary between
Print-Job/Create-Job and Cancel-Job in order for Cancel-Job to work, but
it is also desirable for other operations. For example, Get-Jobs may
give more information about job submitted by the caller of this
operation.

NOTE: This specification does not define  how the mapper maps: (1) the
LPD printer-name to the IPP "printer-uri" or (2) the LPD job-number to
the IPP "job-uri".

NOTE: This specification does not specify how the mapper maps the LPD
user-name to the IPP job-originating-user because the mapper may use its
own user-name with jobs.


4. Mapping of LPD Control File Lines to IPP Parameters

This section describes the mapping from LPD control file lines (called
`functions') to IPP operation input parameters. The mapper receives the
control file lines via the LPD receive-control-file sub-command..  Each
of the LPD functions  appear as sub-sections of section 7 of RFC 1179.

In LPD control file lines, the text operands have a maximum length of 31
or 99 while IPP input parameters have a maximum of 255 characters.
Therefore, no data is lost.

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The mapper converts each supported LPD function to its corresponding IPP
parameter as defined by tables in the subsections that follow. These
subsections group functions according to whether they are:

  .  required with a job,
  .  optional with a job
  .  required with each document.

In the tables below, each LPD value is given a name, such as `h'. If an
IPP value uses the LPD value, then the IPP value column contains the LPD
name, such as `h' to denote this.  Otherwise, the IPP value column
specifies the literal value.


4.1 Required Job Functions

The following LPD functions MUST be in a received LPD job. The mapper
MUST receive each of the following LPD functions and MUST include the
information as a parameter with each IPP job. The functions SHOULD be in
the order `H', `P' and they SHOULD be the first two functions in the
control file, but they MAY be anywhere in the control file and in any
order.

LPD function                      IPP

name value   description          name          value

H    h       Originating Host                   h (in security layer)

P    u       User identification  requesting-   u (and in security
                                  user-name     layer)

             none                 ipp-          `true'
                                  attribute-
                                  fidelity


A mapper MAY sends its own host rather than the client's host, and a
mapper MAY send its own user-name as user identification rather than the
client user. But in any case, the values sent MUST be compatible with
the Cancel-Job operation. The IPP operation MAY have no way to specify
an originating host-name.

The mapper MUST include ipp-attribute-fidelity =true so that it doesn't
have to determine which attributes a printer supports.


4.2 Optional Job Functions

The following LPD functions MAY be in a received job. These function
SHOULD follow the required job functions and precede the document
functions, but they MAY be anywhere in the control file.


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If the mapper receives such an LPD function, the mapper MUST include the
corresponding IPP attribute with the value converted as specified in the
table below.  If the mapper does not receive such an LPD attribute, the
mapper MUST NOT include the corresponding IPP attribute, except the `L'
LPD function whose absence has a special meaning as noted in the table.

LPD function                    IPP

name value   description        name           value

J    j       Job name for       job-name       j
             banner page

L    l       Print banner page  job-sheets     `standard' if `L' is
                                               present

                                               `none' if `L' is present

M    m       Mail When Printed                 IPP has no notification
                                               mechanism. To support
                                               this LPD feature, the
                                               gateway must poll


4.3 Required Document Functions

The mapper MUST receive one set of the required document functions with
each copy of a document, and MUST include the converted information as
parameters with each IPP document

If the control file contains required and recommended document
functions, the required functions SHOULD precede the recommended ones
and if the job contains multiple documents, all the functions for each
document are grouped together as shown in the example of section 6.3
"Required Document Functions". However, the document functions MAY be in
any order.

LPD function                    IPP

name  value  description         name              value

f     fff   Print formatted     document-format   'application/octet-
            file                                  stream'

l     fff   Print file leaving  document-format   'application/octet-
            control characters                    stream'

o     fff   Print Postscript    document-format   'application/
            output file                           PostScript'

                                copies            see note


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Note: In practice, the `f' LPD function is often overloaded. It is often
used with any format of document data including PostScript and PCL data.

Note: In practice, the `l' LPD function is often used as a rough
equivalent to the `f' function.

Note: When RFC 1179 was written, no implementation supported the `o'
function; instead `f' was used for PostScript. Windows NT now sends `o'
function for a PostScript file.

Note: the value `fff' of the `f', `l' and `o' functions is the name of
the data file as transferred, e.g. "dfA123woden".

If the mapper receives any other lower case letter, the mapper MUST
reject the job because the document contains a format that the mapper
does not support.

The mapper determines the number of copies by counting the number of
occurrences of each `fff' file with one of the lower-case functions
above. For example, if `f dfA123woden' occurs 4 times, then copies has a
value of 4. Although the LPD protocol allows the value of copies to be
different for each document, the commands and the receiving print
systems don't support this.


4.4 Recommended Document Functions

The mapper SHOULD receive one set of the recommended document functions
with each document, and SHOULD include the converted information as
parameters with each IPP document. The functions SHOULD be received in
the order `U' and `N', but they MAY arrive in any order.

LPD function                        IPP

name  value   description           name              value

U     fff                           ignored

N     n       Name of source file   document-name     n


Note: the value `fff' of the `U' function is the name of the data file
as transferred, e.g. "dfA123woden".


5. Mapping from IPP operations to LPD commands

If the IPP-to-LPD mapper receives an IPP operation, the following table
summarizes the LPD command that it uses. Each section below gives the
detail. Each of the following sub-sections appear as sub-sections of
section 3 in the document "Internet Printing Protocol/1.0: Model and
Semantics" [ipp-mod].


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IPP operation                     LPD command

Print-Job or Print-URI or         receive-a-printer-job
Create-Job/Send-Document/Send-URI and then print-any-waiting-jobs

Validate-Job                      implemented by the mapper

Cancel-Job                        remove-jobs

Get-Printer-Attributes, Get-Job-  send queue state (short or long)
Attributes or Get-Jobs


5.1 Print-Job

The mapper MUST send the following commands in the order listed below:

  .  receive-a-printer-job command
  .  both receive-control-file sub-command and receive-data-file
     sub-command
     (unspecified order, see Note below)
  .  print-any-waiting-jobs command,
     except that if the mapper is sending a sequence of receive-a-
     printer-job commands, it MAY omit sending print-any-waiting-
     jobs after any receive-a printer-job command that is neither
     the first nor last command in this sequence

Note: it is recommended that the order of the receive-control-file sub-
command and the receive-data-file sub-command be configurable because
either order fails for some print systems. Some print systems assume
that the control file follows all data files and start printing
immediately on receipt of the control file. When such a print system
tries to print a data file that has not arrived, it produces an error.
Other print systems assume that the control file arrives before the data
files and start printing when the first data file arrives. Such a system
ignores the control information, such as banner page or copies.

NOTE: This specification does not define the mapping between the IPP
printer-uri and the LPD printer-name.

The mapper MUST send the IPP parameters and attributes received from the
operation to the LPD printer by using the LPD receive-control-file sub-
command. The mapper MUST create the LPD job-number for use in the
control file name, but the receiving printer MAY, in some circumstances,
assign a different job-number to the job. The mapper MUST create the IPP
job-id and IPP job-uri returned in the Print-Job response.

NOTE: This specification does not specify how the mapper determines the
LPD job-number, the IPP job-id or the IPP job-uri of a job that it
creates nor does it specify the relation ship between the IPP job-uri,
IPP the job-id and the LPD job-number, both of which the mapper creates.
However, it is likely that the mapper will use the same integer value
for both theLPD  job-number and the IPP job-id, and that the IPP Job-uri
is the printer's URI with the job-id concatenated on the end.
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The mapper MUST send data received in the IPP operation to the LPD
printer by using the LPD receive-data-file sub-command. The mapper MUST
specify the exact number of bytes being transmitted in the number-of-
bytes field of the receive-data-file sub-command. It MUST NOT use a
value of 0 in this field.

If the mapper, while it is transmitting a receive-a-printer-job command
or sub-command, either detects that its IPP connection has closed or
receives a Cancel-Job operation,  the mapper MUST terminate the LPD job
either with the abort sub-command or the remove-jobs command.

Error code conversion is not specified in this document..


5.2 Print-URI

The mapper MUST handle this operation in the same way as a Print-Job
operation except that it MUST obtain data referenced by the "document-
uri" parameter and MUST then treat that data as if it had been received
via a Print-Job operation.


5.3 Validate-Job

The mapper MUST perform this operation directly. Because LPD supports
very few attributes, this operation doesn't have much to check.


5.4 Create-Job

The mapper MUST handle this operation like Print-Job, except

  .  the mapper MUST send  the control file  after it has  received
     the last  Send-Document  or  Send-URI  operation  because  the
     control file  contains  all the  document-name  and  document-
     format values  specified  in the  Send-Document  and  Send-URI
     operations.
  .  the mapper MUST perform one receive-data-file sub-command  for
     each Send-Document or Send-URI  operation received and in  the
     same order received.
  .  the mapper MUST send the control file either before all data
     files or after all data files.
     (See the note in the section on Print-Job about the dilemma of
     sending the control file either before or after the data
     files.

5.5 Send-Document

The mapper performs a receive-data-file sub-command on the received
data. See the preceding section 5.4 "Create-Job" for the details.




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5.6 Send-URI

The mapper MUST obtain the data referenced by the "document-uri"
parameter, and MUST then treat that data as if it had been received via
a Send-Document operation. See the preceding section 5.5 "Send-Document"
for the details.


5.7 Cancel-Job

The mapper MUST perform a remove-jobs command with the following
parameters:

  .  the printer is the one to which the job was submitted, that is
     the IPP printer-uri is  mapped to an  LPD printer-name by  the
     same mechanism as for all commands.
  .  the agent is the authenticated user-name of the IPP client,
  .  the  job-number  is  the  job-id  returned  by  the  Print-Job
     command, that is, the LPD job-number has the same value as the
     IPP job-id for likely implementations.


5.8 Get-Printer-Attributes

LPD severely limits the set of attributes that the mapper is able to
return in its response for this operation. The mapper MUST support, at
most, the following printer attributes:

  .  printer-state
  .  printer-state-reasons

The mapper uses either the long or short form of the "send queue state"
command.

The mapper MUST assume that the LPD response that it receives has the
format and information specified in section 3.3 "Send queue state
(short)"  and section 3.4 "Send queue state (long)". The mapper MUST
determine the value of each requested attribute by using the inverse of
the mapping specified in the two aforementioned sections.

Note: the mapper can determine the response from the printer-status line
without examining the rest of the LPD response.


5.9 Get-Job-Attributes

LPD severely limits the set of attributes that the mapper is able to
return in its response for this operation. The mapper MUST support, at
most, the following job attributes:

  .  number-of-intervening-jobs
  .  job-originating-user-name
  .  job-id
  .  document-name
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  .  job-k-octets
  .  copies

The mapper uses either the long or short form of the "send queue state"
command. If it receives a request for the "job-k-octets" or  "copies"
and supports the attribute it MUST use the long form; otherwise, it MUST
use the short form.

Note: the value of job-k-octets is the value in the short form divided
by the number of "copies" which is on the long form only. Its value can
also be determined by adding the "size" field values for each document
in the job in the long form.

The mapper MUST assume that the LPD response that it receives has the
format and information specified in section 3.3 "Send queue state
(short)"  and section 3.4 "Send queue state (long)". The mapper MUST
determine the value of each requested attribute by using the inverse of
the mapping specified in the two aforementioned sections.

Note: when the mapper uses the LPD short form, it can determine the
response from the single LPD line that pertains to the job specified by
the Get-Job-Attributes operation.

NOTE: the mapper can use its correspondence between the IPP job-id, job-
uri and the LPD job-number.


5.10 Get-Jobs

The mapper MUST perform this operation in the same way as Get-Job-
Attributes except that the mapper converts all the LPD job-lines, and
the IPP response contains one job object for each job-line in the LPD
response..


6. Mapping of IPP Parameters to LPD Control File Lines

This section describes the mapping from IPP operation input parameters
to LPD control file lines (called `functions'). The mapper receives the
IPP operation input parameters via the IPP operation.  Each of the IPP
operation input parameters appear as sub-sections of section 3 and 4.2
in the IPP model document [ipp-mod].

In the context of LPD control file lines, the text operands have a
maximum length of 31 or 99 while IPP input parameters have a maximum of
255 characters.  Therefore, there may be some data loss if the IPP
parameters exceed the maximum length of the LPD equivalent operands.

The mapper converts each supported IPP parameter to its corresponding
LPD function as defined by tables in the subsections that follow. These
subsections group functions according to whether they are:

  .  required with a job,
  .  optional with a job
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  .  required with each document.

In the tables below, each IPP value is given a name, such as `h'. If an
LPD value uses the IPP value, then the LPD value column contains the IPP
name, such as `h' to denote this.  Otherwise, the LPD value column
specifies the literal value.


6.1 Required Job Functions

The mapper MUST include the following LPD functions with each job, and
they MUST have the specified value. They MUST be the first functions in
the control file and they MUST be in the order "H" and then "P".

IPP                           LPD function

name                  value   name  value         description

(perhaps in security  h       H     gateway host  Originating Host
layer)

requesting-user-name  u       P     u             User identification
and in the security
layer


A mapper MUST sends its own host rather than the client's host, because
some LPD systems require that it be the same as the host from which the
remove-jobs command comes.  A mapper MAY send its own user name as user
identification rather than the client user. But in any case, the values
sent MUST be compatible with the LPD remove-jobs operation.


6.2 Optional Job Functions

The mapper MAY include the following LPD functions with each job. They
MUST have the specified value if they are sent. These functions, if
present, MUST follow the require job functions, and they MUST precede
the required document functions.

IPP attribute                      LPD function

name           value               name value   description

job-name       j                   J    j       Job name for banner
                                                page

job-sheets     `standard'          L    u       Print banner page

job-sheets     `none'                           omit `L' function


Note: `L' has special meaning when it is omitted. If `J' is omitted,
some undefined behavior occurs with respect to the banner page.
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6.3 Required Document Functions

The mapper MUST include one set of  the following LPD functions with
each document, and they MUST have the specified values. For each
document, the order of the functions MUST be `f', `U' and then `N',
where `f' is replicated once for each copy.

IPP attribute                       LPD function

name        value                   name  value  description

document-   'application/octet-     f     fff    Print formatted file
format      stream' or
            'application/PostScript'

copies      c                                    replicate `f' `c'
                                                 times

none                                U     fff    Unlink data file

document-   n                       N     n      Name of source file
name


Note: the value `fff' of the `f' and `U' functions is the name of the
data file as transferred, e.g. "dfA123woden".

Note: the mapper MUST NOT send the `o' function

ISSUE: should we register DVI, troff or ditroff?

If the mapper receives no "ipp-attribute-fidelitybest-effort" or it has
a value of false, then the mapper MUST reject the job if it specifies
attributes or attribute values that are not among those supported in the
above tables.

Below is an example of the minimal control file for a job with three
copies of two files `foo' and `bar':

  H tiger
  P jones
  f dfA123woden
  f dfA123woden
  f dfA123woden
  U dfA123woden
  N foo
  f dfB123woden
  f dfB123woden
  f dfB123woden
  U dfB123woden
  N bar


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7. Security Considerations

There are no security issues beyond those covered in the IPP Encoding
and Transport document [ipp-pro], the IPP model document [ipp-mod] and
the LPD document [rfc1179].


8. References

 [ipp-lpd]  Herriot, R., Hastings, T., Jacobs, N., Martin, J., "Mapping
       between LPD and IPP Protocols", draft-ietf-ipp-lpd-ipp-map-
       04.txt, June 1998.

[ipp-mod]   Isaacson, S., deBry, R., Hastings, T., Herriot, R., Powell,
       P., "Internet Printing Protocol/1.0: Model and Semantics" draft-
       ietf-ipp-mod-10.txt, June, 1998.

[ipp-pro] Herriot, R., Butler, S., Moore, P., Tuner, R., "Internet
       Printing Protocol/1.0: Encoding and Transport", draft-ietf-ipp-
       pro-06.txt, June, 1998.

[ipp-rat]   Zilles, S., "Rationale for the Structure and Model and
       Protocol for the Internet Printing Protocol", draft-ietf-ipp-
       rat-03.txt, June, 1998.

[ipp-req]   Wright, D., "Design Goals for an Internet Printing
       Protocol", draft-ietf-ipp-req-02.txt, June, 1998.

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

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

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

[abnf] D.   Crocker et al., "Augmented BNF for Syntax Specifications:
       ABNF", draft-ietf-drums-abnf-05.txt.


9. Author's Addresses

Robert Herriot (editor)              Norm Jacobs
Sun Microsystems Inc.                Sun Microsystems Inc.
901 San Antonio.Road., MPK-17        1430 Owl Ridge Rd.
Mountain View, CA 94043              Colorado Springs, CO 80919

Phone:  650-786-8995                 Phone:  719-532-9927
Fax: 650-786-7077                    Fax:   719-535-0956
Email:  robert.herriot@eng.sun.com   Email:
                                     Norm.Jacobs@Central.sun.com

Thomas N. Hastings                   Jay Martin
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Xerox Corporation                    Underscore, Inc.
701 S. Aviation Blvd., ESAE-231      41-C Sagamore Park Road
El Segundo, CA 90245                 Hudson, NH 03051-4915

Phone: 310-333-6413                  Phone:  603-889-7000
Fax:   310-333-5514                  Fax:  603-889-2699
EMail: hastings@cp10.es.xerox.com    Email:  jkm@underscore.com


10. Appendix A: ABNF Syntax for response of Send-queue-state (short)

The syntax in ABNF for the response to the LPD command `send-queue-state
(long)' is:

  status-response = empty-queue / nonempty-queue
  empty-queue = "no-entries" LF
  nonempty-queue = printer-status LF heading LF *(job LF)
  printer-status =  OK-status / error-status
  OK-status = printer-name SP "ready and printing" LF
  error-status = < implementation dependent status information >
  heading = "Rank" 3SP "Owner" 6SP "Job" 13SP "Files"
                  23SP "Total Size" LF
                     ; the column headings and their values below begin
  at the columns
                     ; 1, 8, 19, 35 and 63
  job = rank *SP owner *SP job *SP files *SP total-size "bytes"
                    ; jobs are in order of oldest to newest
  rank = "active" / "1st" / "2nd" / "3rd" / integer "th"
                    ; job that is printing is "active"
                    ; other values show position in the queue
  owner = <user name of person who submitted the job>
  job = 1*3DIGIT   ; job-number
  files = <file name> *( "," <file name>) ; truncated to 24 characters
  total-size = 1*DIGIT  ; combined size in bytes of all documents

11. Appendix B: ABNF Syntax for response of Send-queue-state (long)

The syntax in ABNF for the response to the LPD command `send-queue-state
(long)' is:

  status-response = empty-queue / nonempty-queue
  empty-queue = "no-entries" LF
  nonempty-queue = printer-status LF  *job
  printer-status =  OK-status / error-status
  OK-status = printer-name SP "ready and printing" LF
  error-status = < implementation dependent status information >
  job = LF line-1 LF line-2 LF
  line-1 = owner ":" SP rank 1*SP "[job" job SP host "]"
  line-2 =  file-name 1*SP document-size "bytes"
        ; jobs are in order of oldest to newest
  rank = "active" / "1st" / "2nd" / "3rd" / integer "th"
          ; job that is printing is "active"
          ; other values show position in the queue
  owner = <user name of person who submitted the job>
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  job = 1*3DIGIT
  file-name = [ 1*DIGIT  "copies of" SP ] <file name>
                ; truncated to 24 characters
  document-size = 1*DIGIT  ;size of single copy of the document.

12. Appendix C: Unsupported LPD functions

The follow LPD functions have no IPP equivalent. The LPD-to-IPP mapper
ignores them and the IPP-to-LPD mapper does not send them.

     LPD command

     name   description

     C      Class for banner page

     I      Indent Printing

     H      Host of client

     M      Mail when printed

     S      Symbolic link data

     T      Title for pr

     W      Width of output

     1      troff R font

     2      troff I font

     3      troff B font

     4      troff S font


The follow LPD functions specify document-formats which have no IPP
equivalent, unless someone registers them. The LPD-to-IPP mapper rejects
jobs that request such a document format, and the IPP-to-LPD mapper does
not send them.

     LPD command

     name   description

     c      Plot CIF file

     d      Print DVI file

     g      Plot file

     k      reserved for Kerberized clients and servers

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     LPD command

     name   description

     n      Print ditroff output file

     p      Print file with 'pr' format

     r      File to print with FORTRAN carriage control

     t      Print troff output file

     v      Print raster file

     z      reserved for future use with the Palladium
            print system


13. Appendix D: Full Copyright Statement

Copyright (C)The Internet Society (1997). All Rights Reserved

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

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

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










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