TCP/IP Management Programming Manual

HP NonStop TCP/IP Management Programming Manual—529636-001
3-1
3 Elements of SPI Messages
The SPI procedures facilitate communication between a management application and
the TCP/IP subsystem. These procedures allow a management application to build
commands in an SPI message format to be sent through SCP to the subsystem. These
procedures also allow a management application to decode the responses from the
subsystem that have been sent through SCP in an SPI message format. However,
NonStop OS procedures, are used to transport SPI-formatted commands and
responses between a management application and SCP, and between SCP and a
subsystem. For details on message transport, see the SPI Programming Manual.
SPI procedures are also used to obtain complete event messages from the EMS
consumer distributor process. However, the EMS procedure EMSGET is used to
extract tokens from event messages, and the EMS procedure EMSTEXT is used to
obtain text versions of event messages. Like commands and responses sent through
SCP, event messages are sent and received in an SPI message format.
The commands sent to the subsystem and the responses and event messages
received from the subsystem are made up of tokens. A token can be a single value or
a structure made up of several values. The concept of tokens is described in the SPI
Programming Manual. For an explanation of the tokens present in multiple commands,
responses, or event messages for the TCP/IP subsystem, see Section 5, Common
Definitions.
This manual does not attempt to give a complete explanation of tokens; it provides
subsystem-specific information about the tokens used to communicate with the TCP/IP
subsystem. General information about tokens can be found in the SPI Programming
Manual, and information about tokens common to all data communications subsystems
can be found in the SPI Common Extensions Manual.
Definition Files
Definition files supplied by HP provide declarations of commonly needed tokens and
other variables, in addition to structures and values. The declaration names in these
files have a standard form that identifies the definition file they come from and what the
declaration defines. In addition, each source of definitions, such as the TCP/IP
subsystem or SPI, has associated with it a set of five definition files: one in TAL, one in
COBOL, one in TACL, one in C, and one in DDL. The definition files in TAL, COBOL,
C, and TACL are derived from the definition file in DDL.
Note. SCP is responsible for the communication between SCP and the TCP/IP subsystem.
Your management application needs to be concerned only with the steps enumerated in
Section 2, Management Programming.