IPP Mail Archive: IPP> New Internet-Draft from the IPP WG

IPP Mail Archive: IPP> New Internet-Draft from the IPP WG

IPP> New Internet-Draft from the IPP WG

Carl-Uno Manros (manros@cp10.es.xerox.com)
Wed, 5 Aug 1998 18:16:56 PDT

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Please find attached a new Internet-Draft from the IPP WG to be discussed
in the Chicago Meeting.

Title: Internet Printing Protocol Scheme
Reference: <drafts-ietf-ipp-ipp-scheme-00>
Date: August 7, 1998

Abstract:

IPP is an application level protocol that can be used for distributed
printing on the Internet. Related IPP documents:

Design Goals for an Internet Printing Protocol
Internet Printing Protocol/1.0: Model and Semantics
Internet Printing Protocol/1.0: Encoding and Transport

This document decribes a possible solution to an IESG request for a
separate naming scheme for IPP. This is for further discussion, no
consensus is yet reached on this in the IPP WG.

Carl-Uno Manros
IETF IPP WG Chair

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INTERNET-DRAFT

<draft-ietf-ipp-ipp-scheme-00.txt> Carl-Uno Manros
Xerox Corporation

August 7, 1998 Expires March 7, 1999

Internet Printing Protocol Scheme

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), ds.internic.net (US East Coast), or
ftp.isi.edu (US West Coast).

Abstract

IPP is an application level protocol that can be used for distributed
printing on the Internet. Related IPP documents:

Design Goals for an Internet Printing Protocol
Internet Printing Protocol/1.0: Model and Semantics
Internet Printing Protocol/1.0: Encoding and Transport

This document decribes a possible solution to an IESG request for a
separate naming scheme for IPP. This is for further discussion, no
consensus is yet reached on this in the IPP WG.

Introduction

The quick summary is that IPP should support a new scheme 'ipp',
which clients and servers use in IPP attributes. Such attributes are
in a message body whose Content-Type is application/ipp. A client
maps 'ipp' URLs to 'http' URLs, and then follows the HTTP/1.1 rules
for constructing a Request-Line and HTTP headers.

The IPP document will not prohibit implementations from supporting
other schemes in IPP attributes, but such support is not defined by
this document.

Details

August 7, 1998 Expires March 7, 1999
Internet Printing Protocol Scheme

A client and an IPP object (i.e. the server) SHOULD support the 'ipp'
scheme in the following IPP attributes. Each of these attributes
identifies a printer or job object. The 'ipp' scheme is not intended
for use in 'uri' valued attributes not in this list.

job attributes -
job-uri
job-printer-uri

printer attributes -
printer-uri-supported

operation attributes -
job-uri
printer-uri

If the scheme of the target URL in a request (i.e. the value of
"printer-uri" or "job-uri" operation attribute) is some scheme 'x',
other than 'ipp', the behavior of the IPP object is not defined by
this document. However, it is RECOMMENDED that if an operation on an
IPP object creates a new value for any of the above attributes, that
attribute has the same scheme 'x'. It is also RECOMMENDED that if an
IPP object returns any of the seven attributes above in the response,
that the IPP object returns those URL values as is, regardless of the
scheme of the target URL.

If the client obtains a target URL from a directory service, the
scheme of the target URL SHOULD be 'ipp'. If the scheme is not
'ipp', the behavior of the client is not defined by this document,
but it is RECOMMENDED that the client use the URL as is as the target
URL.

Although user interfaces are beyond the scope of this document, it is
RECOMMENDED that if software exposes the URL values of any of the
above seven attributes to a human user, that the human see the URL as
is.

When a client sends a request, it MUST convert an 'ipp' target URL to
an 'http' target URL for use in the HTTP Request-Line and HTTP
headers as specified by HTTP/1.1. However, the 'ipp' target URL
remains as is for the value of the "printer-uri" or "job-uri"
attribute in the message body. If the scheme of the target URL is
not 'ipp', the behavior of the client is not defined by this
document, but it is RECOMMENDED that the client use the target URL as
is in the Request-Line and HTTP headers.

A client converts an 'ipp' URL to an 'http' URL by:

1) replacing the 'ipp' scheme by 'http'
2) adding an explicit port 631 if the URL does not contain an
explicit port.

When an IPP client sends a request directly (i.e. no proxy) to an
'ipp' URL such as "ipp://myhost.com/myprinter/myqueue", it MUST open
a TCP connection to some port (this example uses the IPP default port

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August 7, 1998 Expires March 7, 1999
Internet Printing Protocol Scheme

631) on some host ("myhost.com" in this example) with the following
headers:

POST /myprinter/myqueue HTTP/1.1
Host: myhost.com:631
Content-type: application/ipp
Transfer-Encoding: chunked
...

"printer-uri" "ipp://myhost.com/myprinter/myqueue" (encoded in
application/ipp message body)

...

When an IPP client sends a request via a proxy, such as
"myproxy.com", to an 'ipp' URL, such as
"ipp://myhost.com/myprinter/myqueue", it MUST open a TCP connection
to some port (8080 in this example) on some proxy ("myproxy.com" in
this example) with the following headers:

POST http://myhost.com:631/myprinter/myqueue HTTP/1.1
Host: myproxy.com:8080
Content-type: application/ipp
Transfer-Encoding: chunked
...

"printer-uri" "ipp://myhost.com/myprinter/myqueue" (encoded in
application/ipp message body)

...

The proxy then connects to the IPP origin server with headers that
are the same as the "no-proxy" example above.

References

[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-REQ]

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

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August 7, 1998 Expires March 7, 1999
Internet Printing Protocol Scheme

Author's Address

Carl-Uno Manros
Xerox Corporation
701 Aviation Blvd.
El Segundo, CA 90245
manros@cp10.es.xerox.com

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Carl-Uno Manros
Principal Engineer - Advanced Printing Standards - Xerox Corporation
701 S. Aviation Blvd., El Segundo, CA, M/S: ESAE-231
Phone +1-310-333 8273, Fax +1-310-333 5514
Email: manros@cp10.es.xerox.com
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