OSI/MHS Gateway Programmatic Interface (GPI) Programming Guide

EDI Concepts
OSI/MHS Gateway Programmatic Interface (GPI) Programming Guide—424822-001
D-2
EDI Message (EDIM) Structure
In addition to the MTS, the EDIMS also consists of numerous peripheral objects of three
kinds: EDI user agents (EDI-UAs), EDI access units (EDI-AUs), and EDI message
stores (EDI-MSs). These peripheral objects can be viewed as access points for EDI
users; that is, trading partners which exchange EDI interchanges.
As shown in Figure D-1, a trading partner can also access the MTS directly through a
gateway linked to an MTA. In this case, the MTA is an OSI/MHS subsystem, and the
gateway is the GPI. You can use the GPI to develop gateway applications that
communicate with EDI-UAs, EDI-AUs, and EDI-MSs.
As an example of EDI in action, suppose the trading partner on the left in Figure D-1 is
a manufacturing company. Suppose that company ordered parts electronically from the
trading partner on the right, a parts distributor. Upon receiving a purchase order
electronically, a gateway application for the distributor might automatically determine
the cost of the parts and reply with an electronic invoice. After the invoice and parts are
received, the buyer might respond with payment electronically.
EDI Message (EDIM) Structure
An EDIM is a structure defined in CCITT X.435 (EDI) recommendations. It is a well-
defined form that facilitates transfer of an EDI interchange through the X.400 network.
The EDIM sets up transfer of the interchange from originator to recipient(s) according to
X.435 protocols. Figure D-2 shows the relationship between an EDIM and EDI
interchange (in this case, an EDIFACT).
An EDIM has a heading and body. The heading contains information that describes the
EDI interchange (the information comes from related fields in the interchange itself).
Such information may include, for example, the date and time the interchange was
encoded as an EDIM. It also includes detailed information about originator and
recipients.
Figure D-1. The EDI Messaging System
905CDT .CDD
Trading
Partner
EDI UA EDI MS
EDI AU
MTS
EDI Messaging System
Trading
Partner
EDI UA
OSI/MHS
GPI
MTAMTA