The Message Store
The Message store was added to X.400 recommendations in 1988 to remove some of the problems related
to the availability of P.C.s and to provide MTS with a front end to make it more like an electronic mail
service. A particular instance of an MS is an object that is located between the UA and an MTA, serves a
single UA and provides the following services:
- When an MTA has a message to deliver to a UA served by an MS, it delivers the message to the MS
store instead of the UA. The retrieves the message from the MS at its convenience. From the MTS point of
view, the message is delivered when it is transferred to the MS and the MTA generates a delivery
notification for the message at this time.
- When the user of a UA served by a MS sends a message, the user's UA submits it to the MS instead
of the MTA. The MS, in turn submits the message to the MTA. This is reffered to as indirect submission.
- The MS provides additional functions such as the capability to list or delete messages held by the MS
on behalf of the UA which it serves.
Interfacing the MS with the UA
The UA that accesses the MTS via an MS has access not only to all service elements available to a UA,
which accesses the MTS directly (using the P3 protocol), but also to service elements provided by the MS,
such as the capability to list summaries of the messages held by the MS or the capability to request specific
messages. The X.400 recommendations specify both formats and protocols between the MS and UA as well
as the services provided by the MS to the UA. The interface between a UA and its MS is referred to as P7.
The services and formats provided is described in X.413. The protocols are specified in X.419 and called
MS access protocols.
Back to X.400 Functional model
Back to X.400 document page