OSI/MHS P7 Application Programmatic Interface (P7 API) Manual

Planning and Writing Your Application
OSI/MHS P7 Application Programmatic Interface (P7 API) Manual—424825-001
2-10
Transferring Data
For each active client application, the P7 API can keep track of up to 10 message
submissions for which a response has not yet been received. The P7 API does this
tracking by means of a unique invoke identifier (ID) that is assigned to each
message submission. The P7 API guarantees that a message is sent only once by not
resubmitting the same invoke ID more than once. However, should an error occur
and the message submission not complete successfully, the client application can
resubmit the message with the same invoke ID.
•
Specifies direct submission of messages between the LO group and the MR group,
bypassing the MS group.
When a client application submits a message directly to the MR group, the LO
group:
1. Allocates a PDU identifier (PDU ID) in the MR PDU store.
2. Transfers all of the message in the increments that you specified in the
LOS_DT_SEND_ procedure call.
3. Informs the MR group that it has a message to send.
The MR group assumes responsibility for delivering the message after it receives the
message.
When SUB-RELIABLE-TRANSFER-OFF is specified, the P7 API:
•
Allows messages to be submitted more than once.
In this case, invoke IDs are not saved and duplicate submission is not tracked as is
the case with direct submission.
•
Specifies indirect submission of messages between the LO group and the MR group,
by way of the MS group.
When a client application submits a message indirectly, the LO group:
1. Allocates a PDU ID in the MS PDU store.
2. Transfers all of the message in the increments that you specified in the
LOS_DT_SEND_ procedure call.
3. Informs the MS group that it has a message to send.
The MS group then takes responsibility for the message and performs the same steps
to transfer the message to the MR group as the LO group did to transfer it to the MS
group. After the MR group receives the message, it assumes responsibility for
delivering the message.
By default, this attribute is OFF.
Note. All P7 submission arguments go through the indirect submissions port. When this
manual refers to direct submission, it is not referring to the UA to MTA protocol, referred to in
the X.400 standards as direct submission. Instead, this manual uses the term direct
submission to refer to the implementation of an MS-bypass feature within the Compaq
OSI/MHS subsystem. While the message can pass from the LO group directly to the MR
group, the P7 API is still using the UA to MS P7 protocol.