MIME EDI: MIME Encapsulation of EDI Objects
How to carry electronic data interchange documents as MIME body parts, using three content types.
Crocker, D., "MIME Encapsulation of EDI Objects", RFC 1767, DOI 10.17487/RFC1767, March 1995, <https://www.rfc-editor.org/info/rfc1767>.
@misc{rfc1767,
series = {Request for Comments},
number = 1767,
howpublished = {RFC 1767},
publisher = {RFC Editor},
doi = {10.17487/RFC1767},
url = {https://www.rfc-editor.org/info/rfc1767},
author = {D. Crocker},
title = {{MIME Encapsulation of EDI Objects}},
pagetotal = 7,
year = 1995,
month = mar,
} RFC text
Contents
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", RFC 1521, Bellcore, Innosoft, September 1993.
[Brad89] Braden, R., Editor, "Requirements for Internet Hosts -
Application and Support", STD 3, RFC 1123, Internet
Engineering Task Force, October 1989.
[Croc82] Crocker, D., "Standard for the Format of Internet
Text Messages", STD 11, RFC 822, 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, RFC 821, 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.
ISO Plain Language
On this page
§1What the Specification Does
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.
For the specification effort, the basic building block from EDI is an interchange. The 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, and this specification adds to that repertoire by permitting convenient carriage through Internet email.
Since there are many different EDI specifications, the 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. 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. The last category covers all other specifications, and is Application/EDI-consent.
The document does not change how EDI documents are written. It only says how to label one when it is carried as an email attachment, and it does that with three labels, because there are many EDI standards and a receiver needs to know which family the document belongs to.
§2The Three Content Types
The three content types all share the same shape: the MIME type name is Application, there are no required parameters, and the only optional parameter is CHARSET as defined for MIME. The encoding considerations for all three are that they may need BASE64 or QUOTED-PRINTABLE transfer encoding, and the security considerations point to the separate section of the document.
Application/EDIFACT contains data as specified for electronic data interchange by the EDIFACT specifications. It is a generic mechanism for sending any EDIFACT interchange, and the object is self-defining in terms of indicating which specific EDI objects are included. The rationale given is that the EDIFACT specifications are accepted standards for a class of inter-organization transactions, and this permits their transmission over the Internet via email.
Application/EDI-X12 contains data as specified for electronic data interchange by the ASC X12 specifications. It is a generic mechanism for sending any ASC X12 interchange, again self-defining. The rationale is the same: the ASC X12 EDI specifications are accepted standards for a class of inter-organization transactions, and this permits their transmission over the Internet via email.
Application/EDI-consent contains data as specified for electronic data interchange with the consent of an explicit, bilateral trading partner agreement exchanging the EDI-consent traffic. Use of EDI-consent only provides a standard mechanism for wrapping the EDI objects, and does not specify any of the details about those objects. The rationale is that existing practice for exchanging EDI includes a very wide range of specifications that are not part of the usual accredited standards world; nevertheless, this traffic is substantial and well-established, and the content type provides a means of delimiting such content in a standard fashion. X12 and EDIFACT objects 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.
Two of the three labels name a specific EDI standard family, and the third is a catch-all for everything else. The catch-all is only for documents the two partners have agreed between themselves to exchange in that way.
| Content type | MIME subtype | Required parameters | Optional parameters |
|---|---|---|---|
| Application/EDIFACT THIS RFC | EDIFACT | None | CHARSET |
| Application/EDI-X12 | EDI-X12 | None | CHARSET |
| Application/EDI-consent | EDI-consent | None | CHARSET |
§3Why a Transfer Encoding May Be Needed
The document gives the same encoding note for each of the three content types. 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.
This is the same mechanism MIME uses for any other body part that is not safe to put in a mail message as plain text: the content is transformed into a printable form for transport, and the Content-Transfer-Encoding header says which transformation was used so that the receiver can undo it.
Most EDI text is fine to put straight into an email, but some delimiters are not printable characters, and some payloads are binary. When that happens, MIME's usual transfer encoding carries it, and the header records which encoding was used.
§5A Sample Message
The document gives one example, an EDIFACT interchange sent as a MIME message, to show the gist of the formatting required. The headers are the ordinary mail headers, followed by Mime-Version: 1.0, a Content-Type naming the content type, a Content-Transfer-Encoding, and then the interchange itself in the body.
A single EDI interchange in an email needs no more than the normal mail headers, the MIME version, the content type that says which EDI standard the body follows, and a line saying how the body was encoded for transport.
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>>§7Security Considerations
EDI transactions typically include sensitive data, so 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 that 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.
The 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 that are appropriate to the user requirements, such as those provided by EDI-based standards.
Orders and invoices are business secrets, so this document carries no protection of its own. Whatever security the two trading partners need has to be added on top, either with the security services MIME offers or with whatever their own EDI standards provide.
§10How the Message Reaches the Other Side
The appendix is written for readers who know EDI but not Internet electronic mail. Internet electronic mail follows the classic user agent and mail transfer agent model, in which 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 information such as author and recipient addresses, subject summary, creation date and handling node names, and are defined by RFC 822 and RFC 1123. If the body is structured, it conforms to the rules of MIME. 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 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 has, at least, the components shown in the document: a business program or database, an EDI translator, MIME encapsulation, RFC 822 packaging, mail submission, SMTP relaying, mail delivery, RFC 822 and MIME stripping, another EDI translator, and business processing. The first and last lines show components normal to all EDI activities, so it is only the EDI transmission components that are replaced with Internet modules.
An EDI document still has to be turned into an EDI document at each end; the email carries it in between. The document shows the chain of steps from the business system on the sender's side to the business system on the receiver's side.
Business Program/Data base -> EDI Translator ->
-> MIME encapsulation -> RFC822 packaging -> mail
submission ->
-> SMTP relaying ->
-> mail delivery -> RFC822 & Mime stripping ->
-> EDI Translator -> Business processing