Applications Area                            Kiyoshi Toyoda
INTERNET-DRAFT                                Hiroyuki Ohno
Nov 12, 1997                                      Jun Murai
Expires May 1998                               WIDE Project



                Facsimile over Internet Mail

               <draft-ietf-fax-service-00.txt>




STATUS OF THIS MEMO

This document is an Internet-Draft.  Internet-Drafts are
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Copyright (C) The Internet Society (1997).  All Rights
Reserved.


SUMMARY

This specification provides for carriage of facsimile data
over the Internet. It employs standard protocols and file
formats such as TCP/IP, SMTP[1], POP3[7], MIME[2], and TIFF-
F[3].  It can send images not only to other Internet-aware
fax devices but also to Internet-native systems, such as PCs
with common email readers which can handle MIME mail and
TIFF-F data.


1    SCOPE

A fax-capable device which uses T.30 and the public switched
telephone network, but is also Internet capable is called an
IFAX device.  An IFAX device has an e-mail address.

This specification provides for communication between each
of the following combinations:

     *    IFAX and Internet mail host (personal computer or
          work station)
     *    Two IFAX devices
     *    IFAX and G3FAX (i.e. ITU-T Group 3 FAX[4]) via an
          IFAX relay.
     *    Internet mail host and G3FAX via an IFAX relay

A classic fax device (e.g., G3FAX) has substantial
restrictions due to specifications in the standards, such as
for timers. This specification of message-based fax over the
Internet satisfies a minimum set of requirements, taking
into account the capabilities of a fax machines and PCs
which can generate fax data.

In reality, this specification creates a profile for
Internet mail, rather than creating a distinct "facsimile
over the Internet" service.  The semantics resulting from
the profile are designed to be compatible with T.30
facsimile service, so that gateways between facsimile and
Internet mail can provide that service with very high
fidelity.

The reason for developing this capability as an email
profile is to permit interworking amongst facsimile and
email users.  For example it is intended that existing email
users be able to send normal messages to lists of users,
including facsimile-based recipients, and that other email
recipients shall be able to reply to the original and
continue to include facsimile recipients.  Similarly it is
intended that existing email software work without
modification and not be required to process new, or
different data structures, beyond what is normal for
Internet mail users.  Existing email service standards are
used, rather than replicating mechanisms which are more
tailored to existing facsimile standards, to ensure this
compatibility with existing email service.


2    COMMUNICATION PROTOCOLS

The set of conventions necessary to achieve facsimile-
compatible service cover basic data transport, data document
formats, message (document) addressing, delivery
confirmation, and message security. In this section, the
first 4 are covered.  The remainder are covered in following
sections, along with additional details for addressing and
formats.

2.1  Transport

Data transfer is achieved using any acceptable Internet mail
transfer mechanism.  The typical choice is SMTP, especially
between organizations across the Internet.  As for all
Internet mail, delivery can be effected using SMTP, POP or
IMAP, as appropriate for a local configuration.  For
delivery to classic fax devices via a gateway, Internet mail
delivery refers to transport to the gateway, rather than
transport to the final, classic fax device.

Addressing conforms to Internet mail standards.  For
referencing destinations which are not classic Internet mail
mailboxes, additional mailbox coding conventions are
required and are described below.

2.2  Formats

Standard Internet mail headers and MIME content packaging
also are used.  IFAX gateways may choose to use the contents
of the RFC822 headers to form a cover page, in addition to
any cover page included in the document body.

Unique message identification is achieved with the standard
RFC822 Message-ID header.

The data format of the facsimile image is based on the
minimum set of TIFF-F[3].   Rules for the use of TIFF-F for
the message-based Internet fax application are defined
later.

TIFF-F creates binary data so that proper Content-transfer-
encoding using base64, is necessary when the data are
transported over channels which do not support pure binary.

Multiple fax documents may be aggregated within a single
Internet mail message, by using Multipart/mixed.

2.3  Confirmation

A sending agent MAY request Delivery Service Notification
(DSN [5]/[6]), since this is a natural part of existing
facsimile service and is a standard part of Internet mail. A
receiving agent SHOULD correctly process a DSN request which
accompanies a facsimile-related message.

For such messages, a DSN SHOULD be generated by an email
recipient according to the standard rules for DSNs. If an
offramp gateway supports DSN, it SHOULD generate one upon
receipt of a fax delivery confirmation issued by the
receiving facsimile device.


3  Addressing

3.1  Classic Email Destinations

Messages being sent to normal Internet mail recipients will
use standard Internet mail addresses, without additional
constraints.

3.2  Classic Fax Devices (accessed via an IFAX gateway)

Classic fax devices are accessed via telephone dial-up, by
an IFAX device.  A number of different addressing schemes
are feasible for processing by an IFAX offramp gateway.
This specification provides for only one, to have a single,
simple convention.  However this is not intended to preclude
use of others schemes which are acceptable by private
conventions and which may be candidates for standardization
in the future.

The Internet mail address for such a device MUST encode the
name of the IFAX gateway and the telephone number to be
called.  The destination fax telephone number is in the
local-part (left-hand side) of the address. The name of the
gateway is in the domain name (right-hand-side) of the
address.

An Internet mail address for a classic fax device to be
accessed by an IFAX gateway is in the form:

               FAX-number@IFAX-domain-name

The ABNF specification for the syntax of FAX-number is
defined by "PSTN and fax address in e-mail services"[8].


4  TIFF FORMAT

Message-based Internet Fax applications MUST be able to read
and write minimum set TIFF-F files, per the rules for
creating minimum set TIFF-F files defined in TIFF-F.
Internet fax applications MAY also support TIFF-F field
values that go beyond the minimum set, but not all TIFF-F
readers will support these values.


5    Security

This specification permits the use of existing Internet
mail.  Any security to be provided is provided as part of
the Internet mail infrastructure.

However, existing facsimile service carries a strong
expectation of basic privacy.  As a consequence, the sender
of IFax MAY request data privacy.  The state of Internet
standards, deployment and use for security technology
permits a number of different implementations which can
provide adequate degrees of privacy.

Existing facsimile service does not carry any mechanism for
authentication, however it does permit non-authenticated
identification of senders.  The From: field string shall be
used for this purpose.


6    REFERENCES

[1]  Crocker, D., "Standard for the Format of ARPA
     Internet Text Messages", STD 11, RFC 822, University of
     Delaware, August l982.

[2]  Borenstein, N., and N. Freed, "MIME (Multipurpose
     Internet Mail Extension) Part One: Mechanisms for
     Specifying and Describing the Format of Internet
     Message Bodies", RFC 1521, Bellcore and Innosoft,
     September 1993.

[3]  Glenn Parsons, James Rafferty, "Tag Image File
     Format(TIFF)-Application F", Network Working Group
     Internet Draft, September 18,1997

[4]  ITU-T (CCITT), Recommendations T.4 and T.30

[5]  K. Moore, "SMTP Service Extension for Delivery
     Status Notifications", RFC 1891, January 1996

[6]  K. Moore, G. Vaudreuil, "An Extensible Message
     Format for Delivery  Status Notifications", RFC 1894,
     January 1996

[7]  J. Myers, M. Rose, "Post Office Protocol - Version 3",
     STD 53, RFC 1939, May 1996.

[8]  C. Allocchio "PSTN and fax address format in e-
     mail services", Network Working Group Internet Draft,
     November 1997


7   Author's Addresses


Kiyoshi Toyoda
Matsushita Graphic Communication Systems, Inc.
2-3-8 Shimomeguro, Meguro-ku
Tokyo 153 Japan
Fax: +81 3 5434 7166
EMail: ktoyoda@rdmg.mgcs.mei.co.jp


Hiroyuki Ohno
Tokyo Institute of Technology
2-12-1 O-okayama, Meguro-ku
Tokyo 152 Japan
FAX: +81 3 5734 2754
EMail: hohno@is.titech.ac.jp


Jun Murai
Keio University
5322 Endo, Fujisawa
Kanagawa 252 Japan
Fax: +81 466 49 1101
EMail: jun@wide.ad.jp


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