NBT Manual

Glossary
NBT Manual—424773-001
Glossary-18
SPI message
SPI message. In DSM programmatic interfaces, a message specially formatted by the SPI
procedures for communication between a management application and a subsystem or
between one subsystem and another. An SPI message consists of a collection of tokens.
Note that an SPI message is a single block of information sent at one time, as one
interprocess message. There are two types of SPI messages, distinguished by different
sets of tokens in the header: command and response messages, and event messages.
SPI procedures. In DSM, the set of Guardian procedures used to build and decode buffers
for use in system and network management and in certain other applications.
SPI standard definitions. In DSM programmatic interfaces, the set of declarations available
for use with the SPI procedures, regardless of the subsystem. There is also a set of
subsystem-specific declarations for each subsystem, and some sets of declarations that
apply to multiple subsystems. An application using SPI needs the SPI standard
definitions and also the subsystem definitions for all subsystems with which it
communicates. See also definition
. Compare data communications standard definitions
or EMS standard definitions.
subject token. In event management, a device, process, or other named entity about which a
given event message has information.
subnet address. An extension of the Internet addressing scheme that allows a site to use a
single Internet address for multiple physical networks. Outside of the site using subnet
addressing, routing continues as usual by dividing the destination address into an
Internet portion and local portion. Gateways and hosts inside a site using subnet
addressing interpret the local portion of the address by dividing it into a physical
network portion and host portion.
subnetwork. One or more intermediate systems that provide relaying and through which end
open systems may establish network connections.
Subnetwork Access Protocol (SNAP). In order to run the TCP/IP protocol suite over IEEE
networks, the Subnetwork Access Protocol (SNAP) defines the interface between the IP
layer and the LLC layer. The interface is accomplished through the use of an extension
of the LLC header that contains a predefined Service Access Point (SAP) for use in the
Source SAP (SSAP) and the Destination SAP (DSAP) fields of the LLC header.
subsystem. (1) The software and/or hardware facilities that provide users with access to a set
of communications service. (2) For DSM, a program or set of processes that manages a
cohesive set of objects. Each subsystem has a process through which applications can
request services by issuing commands defined by that subsystem; in some cases, this
process is the entire subsystem. Many subsystems also have interactive interfaces.
Subsystem Control Facility (SCF). A part of DSM, used to provide a common, interactive
management interface for configuring, controlling, and collecting information from
Compaq data communications products.