TCP/IP TELNET Management Programming Manual

3 Elements of SPI Messages for
the TELNET Subsystem
53474 Tandem Computers Incorporated 3–1
The Subsystem Programmatic Interface (SPI) procedures facilitate communication
between a management application and the TELNET subsystem. These procedures
allow a management application to build commands in SPI message format to be sent
through SCP to the subsystem. These procedures also allow a management
application to decode the responses that have been sent from the subsystem through
SCP in SPI message format. (GUARDIAN 90 procedures, not SPI 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, refer to the Distributed Systems Management (DSM) Programming Manual.)
Note SCP is responsible for the communication between SCP and the TELNET subsystem. Your management
application needs to be concerned only with the details given in Section 2, “Management Programming for
the TELNET Subsystem.”
SPI procedures are also used to obtain complete event messages from the Event
Management Service (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
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
Distributed Systems Management (DSM) Programming Manual. Refer to Section 5 of this
manual, “Common Definitions,” for an explanation of the tokens present in multiple
commands, responses, or event messages for the TELNET subsystem.
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
TELNET subsystem. General information about tokens can be found in the Distributed
Systems Management (DSM) Programming Manual. Information about tokens common
to all data communications subsystems can be found in the Communications
Management Programming Manual.
Definition Files Definition files supplied by Tandem provide declarations of commonly needed tokens
and other variables, as well as 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. Each source of definitions, such as the TELNET subsystem or
SPI, has an associated set of five definition files: one in TAL, one in C, one in
COBOL85, one in TACL, and one in DDL. The definition files in TAL, C, COBOL85,
and TACL are derived from the definition file in DDL.