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-3
Compaq OSI/MHS
X.400 has detailed rules about envelopes and IPM content. The rules that relate to the
Compaq GPI are specified in two protocols:
•
P1, for envelopes
•
P2, for IPM content
Because envelopes are normally seen only by MTAs, P1 is sometimes called the
MTA-to-MTA protocol. Because P2 relates to IPM content, P2 is sometimes called the
IPM protocol.
Compaq OSI/MHS
OSI/MHS is the Compaq implementation of an X.400 MTA. It is a store-and-forward
X.400 messaging switch. Multiple OSI/MHS subsystems can be installed on the same
Compaq NonStop system (Figure C-3).
As an MTA, each Compaq OSI/MHS subsystem can interoperate with any or all of the
following:
•
Other Compaq MTAs on the same NonStop system
•
Compaq MTAs on another NonStop system
•
MTAs other than Compaq MTAs on systems other than Compaq systems
X.400 Gateways
Within the global community, there are also many non-X.400 messaging systems. Each
of these proprietary systems has its own protocols. Interconnecting these systems is a
key role of X.400.
X.400 access is provided by an X.400 gateway. An X.400 gateway connects to X.400
through an MTA.
Figure C-3. Compaq OSI/MHS
903CDT .CDD
Message Handling System
Message Transfer System
User User
MTA
NonStop System
OSI/
MHS
OSI/
MHS