Subsystem Control Point (SCP) Management Programming Manual

Subsystem Control Point (SCP) Management Programming Manual—520619-001
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Introduction
Overview of SCP
Subsystem Control Point (SCP) processes are part of the Distributed Systems
Management (DSM) architecture. An SCP process is a central point through which
management applications and subsystems exchange Subsystem Programmatic Interface
(SPI) messages. Management processes, including the Subsystem Control Facility
(SCF), send SPI messages to an SCP process, which routes each message to a specified
subsystem process. Subsystems return response messages to the SCP process, which
sends each response to the originator of the corresponding request.
Figure 1-1
shows a simplified view of two SCP processes on two nodes routing
messages among three management processes (one of which is an SCF process) and four
subsystems.
A management process can manage an SCP process by sending SPI commands to—
rather than through—the SCP process. The management process directs commands to an
SCP process the same way it directs commands to any other subsystem object: by
specifying the subsystem ID, manager process name, object type, and object name of the
object—in this case the SCP process itself—to which the command is directed. When
the SCP process receives the message and examines the target subsystem and object
identification specified in the request, it recognizes its own identity and processes the
command rather than forwarding it.
Figure 1-1. Overview of the Subsystem Control Point (SCP) Process
SCF
Process
Management
Process $M1
Subsystem A
Process $S1
Subsystem B
Process $S2
SCP
Process
Requests for
$S1, $S2
Replies from
$S1, $S2
Replies from
$S1, $S2
Terminal Communicating With
Subsystem Control Facility (SCF)
Node \LOCAL
SCP
Process
Subsystem A
Process $S1
Management
Process $M2
Subsystem C
Process $S3
Reply for
\LOCAL.$M1
Reply
for $M2
Node \REMOTE
Request from
\LOCAL.$M1
Reply from
\REMOTE.$S1
Request
for $S3
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