Network Working Group D. Crocker
Request for Comments: 1767 Brandenburg Consulting
Category: Standards Track March 1995

MIME Encapsulation of EDI Objects

Status of this Memo

This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.

Table of Contents

1. IntrodUCtion........................................... 1
2. Application/EDIFACT specification...................... 2
3. Application/EDI-X12 specification...................... 3
4. Application/EDI-Consent specification.................. 4
5. Sample edi usage in MIME-based email................... 5
6. References............................................. 5
7. Security Considerations................................ 6
8. Acknowledgments........................................ 6
9. Author's Address....................................... 6
10. Appendix - MIME for EDI users......................... 7

1. Introduction

Electronic Data Interchange (EDI) provides a means of conducting
structured transactions between trading partners. The delivery
mechanism for these types of transactions in a paper world has been
the postal system, so it is to be eXPected that electronic mail would
serve as a natural delivery mechanism for electronic transactions.
This specification permits formatted electronic business interchanges
to be encapsulated within MIME messages [Bore92]. For the
specification effort, the basic building block from EDI is an
interchange.

This specification pertains only to the encapsulation of EDI objects
within the MIME environment. It intends no changes in those objects
from the primary specifications that define the syntax and semantics
of them. EDI transactions take place through a variety of carriage
and exchange mechanisms. This specification adds to that repertoire,
by permitting convenient carriage through Internet email.

Since there are many different EDI specifications, the current
document defines three distinct categories as three different MIME
content-types. One is Application/EDI-X12, indicating that the
contents conform to the range of specifications developed through the
X12 standards organization [X125, X126, X12V]. Another is
Application/EDIFACT, indicating that the contents conform to the
range of specifications developed by the United Nations Working Party
4 Group of Experts 1 EDIFACT boards [FACT, FACV]. The last category
covers all other specifications; it is Application/EDI-consent.

2. APPLICATION/EDIFACT SPECIFICATION

The Application/EDIFACT MIME body-part contains data as specified for
electronic data interchange by [FACT, FACV].

Within EDIFACT, information is specified by:

MIME type name: Application

MIME suBType name: EDIFACT

Required parameters: none

Optional parameters: CHARSET, as defined for MIME

Encoding considerations: May need BASE64 or QUOTED-PRINTABLE
transfer encoding

Security considerations: See separate section in the
document.

Published specification: Contained in the following section.

Rationale: The EDIFACT specifications are
accepted standards for a class of
inter-organization transactions;
this permits their transmission
over the Internet, via email.

Contact-info: See Contact section, below.

Detail specific to MIME-based usage:

This is a generic mechanism for sending any EDIFACT
interchange. The object is self-defining, in terms of
indicating which specific EDI objects are included. Most
EDI data is textual, but special characters such as some
delimiters may be non-printable ASCII or some data may be

pure binary. For EDI objects containing such data, the MIME
transfer mechanism may need to encode the object in Content-
Transfer-Encoding:quoted-printable or base64.

3. APPLICATION/EDI-X12 SPECIFICATION

The Application/EDI-X12 MIME body-part contains data as specified for
electronic data interchange by [X125, X12.6, EDIV].

Within MIME, EDI-X12 information is specified by:

MIME type name: Application

MIME subtype name: EDI-X12

Required parameters: none

Optional parameters: CHARSET, as defined for MIME

Encoding considerations: May need BASE64 or QUOTED-PRINTABLE
transfer encoding

Security considerations: See separate section in the
document.

Published specification: Contained in the following section.

Rationale: The ASC X12 EDI specifications are
accepted standards for a class of
inter-organization transactions;
this permits their transmission
over the Internet, via email.

Contact-info: See Contact section, below.

Detail specific to MIME-based usage:

This is a generic mechanism for sending any ASC X12
interchange. The object is self-defining, in terms of
indicating which specific EDI objects are included. Most
EDI data is textual, but special characters such as some
delimiters may be non-printable ASCII or some data may be
pure binary. For EDI objects containing such data, the MIME
transfer mechanism may need to encode the object in Content-
Transfer-Encoding:quoted-printable or base64.

4. APPLICATION/EDI-CONSENT SPECIFICATION

The Application/EDI-consent MIME body-part contains data as specified
for electronic data interchange with the consent of explicit,
bilateral trading partner agreement exchanging the EDI-consent
traffic. As such, use of EDI-consent only provides a standard
mechanism for "wrapping" the EDI objects but does not specify any of
the details about those objects.

Within MIME, EDI-consent information is specified by:

MIME type name: Application

MIME subtype name: EDI-consent

Required parameters: none

Optional parameters: CHARSET, as defined for MIME

Encoding considerations: May need BASE64 or QUOTED-PRINTABLE
transfer encoding

Security considerations: See separate section in the
document.

Published specification: Contained in the following section.

Rationale: Existing practice for exchanging
EDI includes a very wide range of
specifications which are not part
of the usual, accredited standards
world. Nevertheless, this traffic
is substantial and well-
established. This content type
provides a means of delimiting such
content in a standard fashion.

Contact-info: See Contact section, below.

Detail specific to MIME-based usage:

This is a generic mechanism for sending any EDI object
explicitly agreed to by the trading partners. X12 and
EDIFACT object must be sent using their assigned MIME
content type. EDI-consent is for all other EDI objects, but
only according to trading partner agreements between the
originator and the recipient. Most EDI data is textual,
but special characters such as some delimiters may be non-

printable ASCII or some data may be pure binary. For EDI
objects containing such data, the MIME transfer mechanism
may need to encode the object in Content-Transfer-
Encoding:quoted-printable or base64.

5. SAMPLE EDI USAGE IN MIME-BASED EMAIL

Actual use of EDI within MIME-based mechanisms requires attention to
considerable detail. This section is intended as an example of the
gist of the formatting required to encapsulate EDI objects within
Internet mail, using MIME. To send a single EDIFACT interchange:

To: <<recipient organization EDI email address>>
Subject:
From: <<sending organization EDI email address>>
Date:
Mime-Version: 1.0
Content-Type: Application/EDIFACT
Content-Transfer-Encoding: QUOTED-PRINTABLE

<<standard EDIFACT Interchange goes here>>

6. REFERENCES

[Bore92] Borenstein, N., and N. Freed, "MIME (Multipurpose
Internet Mail Extensions) Part One: Mechanisms for
Specifying and Describing the Format of Internet Message
Bodies", RFC1521, Bellcore, Innosoft, September 1993.

[Brad89] Braden, R., Editor, "Requirements for Internet Hosts -
Application and Support", STD 3, RFC1123, Internet
Engineering Task Force, October 1989.

[Croc82] Crocker, D., "Standard for the Format of Internet
Text Messages", STD 11, RFC822, UDEL, August 1982.

[Rose93] Rose, M., "The Internet Message: Closing the Book
with Electronic Mail", PTR Prentice Hall, Englewood
Cliffs, N.J., 1993.

[Post82] Postel, J., "Simple Mail Transfer Protocol".
STD 10, RFC821, USC/Information Sciences Institute,
August 1982.

[X12V] Data Interchange Standards Association; sets of
specific EDI standards are ordered by their version
number; Washington D.C.

[X125] ANSI X12.5 Interchange Control Structure for
Electronic Data Interchange, Washington D.C.: DISA
[X126] ANSI X12.6 Applications Control Structures for
Electronic Data Interchange, Washington D.C.: DISA

[FACT] United Nations Economic Commission (UN/EC)
Electronic Data Interchange For Administration,
Commerce and Transport (EDIFACT) - Application Level
Syntax Rules (ISO 9735), 1991.

[FACV] Version sets contains the specific syntax documents,
the element and segment dictionaries, and the
transaction/message specifications.

7. SECURITY CONSIDERATIONS

EDI transactions typically include sensitive data, so that
transmission often needs to attend to authentication, data integrity,
privacy, Access control and non-repudiation concerns. This
specification permits transmission of such sensitive data via
Internet mail and other services which support MIME object
encapsulation. For transmission of sensitive data, it is essential
that appropriate security services, such as authentication, privacy
and/or non-repudiation be provided.

This specification does NOT, itself, provide any security-related
mechanisms. As needed and appropriate, such mechanisms MUST be
added, either via Internet MIME-based security services or any other
services which are appropriate to the user requirements, such as
those provided by EDI-based standards.

8. ACKNOWLEDGMENTS

Tom Jones offered introductory text and descriptions of candidate
header options. Numerous working group participants provided review
and comment, especially Walt Houser, Gail Jackson, and Jim Amster.

9. AUTHOR'S ADDRESS

David H. Crocker
Brandenburg Consulting
675 Spruce Dr.
Sunnyvale, CA 94086 USA

Phone: +1 408 246 8253
Fax: +1 408 249 6205
EMail: dcrocker@mordor.stanford.edu

10. APPENDIX - MIME FOR EDI USERS

To assist those familiar with EDI but not with Internet electronic
mail, this Appendix is provided as a very brief introduction,
primarily to give pointers to the relevant specifications. This
section is in no way intended to be a thorough introduction. An
Excellent introductory text is [Rose93].

Internet electronic mail follows the classic user agent/mail transfer
agent model. In this model, user software produces a standardized
object which is transferred via standard exchange protocols.

An Internet electronic mail object comprises a collection of headers,
followed by a (possibly structured) body. The headers specify such
information as author and recipient addresses, subject summary,
creation date, handling node names, and so on, and are defined by
RFC822 and RFC1123 [Croc82, Brad89]. If the body is structured, it
conforms to the rules of the Multipurpose Internet Message Exchange
(MIME) [Bore92]. A structured body may have parts encoded in
different text character sets, or even of entirely different types of
data, such as voice or graphics.

The Simple Mail Transfer Protocol (SMTP) [Post82, Brad89] performs
the primary task of message transmission. User posting and delivery
interactions, between the user agent and the message transfer agent,
on the same machine, are not standardized and are platform-specific.

An EDI-related use of Internet Mime email will have (at least) the
following components:

Business Program/Data base -> EDI Translator ->
-> MIME encapsulation -> RFC822 packaging -> mail
submission ->
-> SMTP relaying ->
-> mail delivery -> RFC822 & Mime stripping ->
-> EDI Translator -> Business processing

The first and last lines show components normal to all EDI activities,
so that it is only the EDI "transmission" components that are replaced
with Internet modules.