ATM Configuration and Management Manual

SCF Commands
ATM Configuration and Management Manual—522307-003
4-3
Subsystem Control Point (SCP)
Subsystem Control Point (SCP)
SCP is a network management process for receiving and redistributing the messages
that SCF sends to its subsystems. SCP provides security, version control, and tracing
support for many of these subsystems.
SCP is used interactively. The interactive interface (using SCF) allows you either to let
a person perform an action or to automate the action. The interactive interface is
described in this section under How SCF Works on page 4-4.
When SCP receives a request, it performs a security check. SCP allows sensitive
commands to be used only by super-group users (255,n) or by users in the group that
created the subsystem. If the security check fails, SCP generates a security-failure
error response.
Next, SCP checks the subsystem destination. If the subsystem is not open, SCP opens
it. Once the subsystem is opened, SCP provides version control by comparing the
request version and the destination subsystem version. If the versions are not
compatible, the request is rejected. If the versions are compatible, SCP sends the
request to the subsystem. Responses are returned directly to the requester.
An application can obtain the version level of the SCP process by directing the
GETVERSION command to the SCP process itself.
SCP supports subsystem traces. SCP can initiate a trace collector process, which
allocates the extended data segment for tracing and writes the trace records to disk as
they accumulate.
SCF Commands
Some SCF commands operate on the objects (devices, subdevices, processes, and so
forth) belonging to each subsystem. The ADD and DELETE commands add objects to
and delete objects from the list of objects in the SCF sphere of control. After SCF
configures an object, you can use the START, STOP, and ABORT commands to
change the state of the object, or you can use the ALTER command to change the
values of selected attributes of the object. You also can use the INFO command to
display the currently configured attribute values for objects and the STATUS command
to display the current dynamic status of objects.
The TRACE command traces the operation of an object. While being traced, the object
continues normal operation, but it passes all message traffic to a trace procedure.
When the trace procedure recognizes a message that meets its selection criteria, it
stores the message in a trace file. You can then use PTrace program commands to
examine the file. Some subsystems use all, or portions of, the SCF trace functions;
other subsystems provide their own trace functions. Refer to the manual for your
particular subsystem for information about how your subsystem implements the
TRACE command.
The ENV command displays the current settings of the SCF command parameters that
establish the program environment.