Distributed Systems Network Management (DSNM) Subsystem Interface Development Guide

General Command Processing Scheme
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109759—Distributed Systems Network Management (DSNM) Subsystem Interface
Development Guide
I Process Development Process
General Command Processing Scheme
As an I process developer, you write a set of procedures that, when executed, form a
command thread that carries out a DSNM command. The general command processing
scheme is listed next. (See Figure 3-3 on page 3-8 for an illustrated example.)
1. When the frame receives a command, it extracts the following command
components and places them in the command context space it allocates to each
thread when it is created:
•
The action to be performed.
•
The command modifiers.
•
A list of objects on which the operation is to be performed (the input object list).
The input object list is made up of a header and a linked list. Each list member
is a formatted object structure, defining one object to which the command is
applied.
2. The frame allocates the command context space, creates an instance of the command
thread, and dispatches the command thread.
3. The thread's overall task is to apply the command to each object in the input object
list by carrying out the following steps:
a. In its simplest form, the thread creates a subsystem command equivalent to the
DSNM command. If the subsystem does not support the operation, the thread
may:
•
Perform the operation by means of a combination of subsystem commands.
•
Simulate the operation. (If the subsystem doesn’t support a particular
operation, the I process itself might be coded to support it. For example, the
I process might keep its own statistics on subsystem objects for which a
STATISTICS operation is not supported.)
•
Treat the operation as a no-operation (but still produce the output required
by the command).
•
Reject the operation with an error.
b. The thread selects an object off the input list and sends it to an appropriate
subsystem CI.
c. The thread returns to the frame to await completion of the CI communication.
d. When a response is received from the CI, the frame redispatches the thread.
e. The thread interprets the response and creates an appropriate response for the
command (see Section 4, “DSNM Command Requirements”).