OSI/MHS Gateway Programmatic Interface (GPI) Programming Guide

Review of X.400 and OSI/MHS
OSI/MHS Gateway Programmatic Interface (GPI) Programming Guide—424822-001
C-2
X.400 Messages
X.400 Messages
There are three types of X.400 messages:
•
User messages (or simply messages)
•
Probes
•
Reports
As shown in Table C-1, the three types differ in structure and purpose.
A message is sent between users. It consists of two parts, envelope and content
(Figure C-2). The envelope contains information used by MTAs to route the message.
Content contains the message substance.
There are several types of content. Of these, interpersonal message (IPM) is the most
common. IPM content is like an office memo. It consists of a heading and body parts.
The heading identifies the body parts. Body parts contain the user information itself.
A probe is sent by a user into the MTS to verify deliverability of a message. A probe
consists of an envelope only. The probe envelope is similar to, but not the same as, the
envelope that would be used for the actual message.
A report is sent from an MTA to a user. It provides status information about an
attempted delivery. The delivery attempt can be related to a probe or message. Like a
message, a report consists of an envelope and content.
Table C-1. X.400 Message Types
Type Purpose Structure
Message Conveys user information Envelope and content
Probe Verifies deliverability Envelope only
Report Conveys status information Envelope and content
Figure C-2. X.400 Message Structures
903CDT .CDD
Message
Envelope
Probe
Envelope
Report
Envelope
Message
Content
No
Content
Report
Content
++ +