OSI/TS Management Programming Manual

2 Communicating With the OSI/TS
Processes
056786 Tandem Computers Incorporated 2–1
This section describes how a management application sends Subsystem Programmatic
Interface (SPI) messages to, receives SPI responses from, and retrieves event messages
generated by the processes in the OSI/TS subsystem.
Communicating
Through SCP
To manage the OSI/TS subsystem, your application sends commands to the TSP
processes, through the Subsystem Control Point (SCP). SCP acts as an intermediary
between applications and data communications subsystems such as OSI/TS. It
forwards some commands to the subsystem processes and performs a few commands
itself.
The Communications Management Programming Manual describes how to run the SCP
process and describes, in detail, communication through SCP. In brief, this
communication consists of the following steps:
1. The application opens the SCP process.
2. The application sends an SPI-format request (an OSI/TS command) to SCP. A
token in the command indicates to SCP that the request is for the OSI/TS
subsystem; another token identifies which OSI/TS process should receive the
command.
3. SCP checks whether the OSI/TS process that is to receive the command is open. If
it is not, SCP opens it.
4. For D-series systems, SCP compares the PINs of both the requesting and receiving
processes. When the TSP process is running at a high PIN it can only request
communication with TSP or NSP servers that are also running at a high PIN. If the
TSP process request communication with low PIN processes, SCP returns the error
ZCOM-ERR-PIN-TOO-BIG.
5. SCP checks whether the version of the OSI/TS subsystem’s DSM interface is
compatible with the application, and it performs security validation on the
request.
6. If all is well, SCP forwards the request to the appropriate OSI/TS process.
7. The OSI/TS process then performs the requested action, formulates a response,
and sends the response to SCP.
8. SCP forwards the response to the application.
9. Before terminating, the application closes the SCP process.
Running a TSP
Process
Before your management application can send commands to OSI/TS through SCP,
you must first install one or more underlying X25AM or TLAM processes (NSP, or
network service provider, processes) using the Tandem system generation program,
SYSGEN. For instructions, refer to the section on configuration of X25AM and TLAM
in the System Generation Manual.
After these processes are installed, you can run the TSP process.