Network operation for SLU P and Finance

The following topics describe how to start an IMS network, how to initiate sessions, the different transaction types, message switching, and IMS commands.

Starting an IMS network
Before a session with IMS can be established for any workstation VTAM®, NCP, controllers, and logical units must be active.
Making IMS ready
IMS must be made ready to receive VTAM logon (session initialization) requests. Ready IMS by issuing the IMS /START command with the DC keyword.
Session initiation (starting workstations)
A session is the logical connection of a workstation to a VTAM application program, such as IMS or the system utilities. A session must be established before data can be transmitted between a workstation and IMS. Message resynchronization is performed during session initiation, unless IMS is cold started.
Suspending output from IMS
If the controller application program does not want or cannot receive any more output from IMS, the program can send the VTAM quiesce-at-end-of-chain (QEC) command to IMS. IMS returns a DR1 and the VTAM quiesce-complete (QC) command. IMS does not send any more output to the workstation until it receives the VTAM release-quiesce (RELQ) command.
Session termination
Session termination releases the workstation from its current logical connection to the VTAM application program. It makes the workstation available for session with other VTAM applications, or communications can be terminated altogether.
Shutting down an IMS network (SLU P)
Shutting down an IMS network may or may not include IMS.
SLU P messages
The primary function of IMS support for the SLU P system is to receive and transmit data for a workstation and to ensure that the data is processed properly.
Send/receive and bracket protocol
The change-direction indicator and bracket protocol, as defined by VTAM, are used to specify the beginning and end of synchronous transmissions and to control the flow of such transmissions.

Parent topic: SLU P and Finance Communication