OSI/TS Management Programming Manual

Glossary
Glossary-20 056786 Tandem Computers Incorporated
SPI procedures. In DSM, the set of Guardian 90 procedures used to build and decode
buffers for use in system and network management and in certain other applications.
These procedures are SSINIT, SSNULL, SSPUT, SSPUTTKN, SSGET, SSGETTKN,
SSMOVE, and SSMOVETKN.
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, definition files. Compare data
communications standard definitions or EMS standard definitions.
SSAP (session service access point). A network-unique address in the Session Layer
through which connections are established and maintained. Also called session
address.
SSEL (session selector). A logical address in the Session Layer through which session
services are made available. A single SSEL can service one or more connections
simultaneously.
SSID. See Subsystem ID.
State-machine error. (1) In the programmatic interface to OSI/AS, an error caused by an
applications making an APS procedure call that invokes a primitive at the wrong time
or under the wrong conditions.
(2) In the event-management interface to OSI/AS, an internal error in the OSI/AS
software that causes the TAPS process to issue an event message.
Station group address. A media access control (MAC) address, common to the same
type of system (that is, intermediate systems or end systems), that is used by a system
to broadcast to all systems of the same type (that is, intermediate systems or end
systems).
Store and forward subnet. Another name for an intermediate system. See intermediate
system.
Subaddress. Another name for port address. See port address.
Subdevice. A logical entity providing access to a physical connection—that is, to a
communications line. There may be one or many subdevices associated with a given
line or process. Exactly what constitutes a subdevice differs depending on the
subsystem. An OSI/AS (TAPS) subdevice is created dynamically by the OSI manager
process when a connection is made and usually lasts only as long as the connection
exists. An OSI/TS (TSP) subdevice is a Guardian 90 subdevice that uniquely identifies
a Transport Layer connection; it can be dynamically created and deleted or it can be
reused after the connection is released. An X25AM subdevice corresponds to an X.25
virtual circuit. TLAM subdevices are of several types: FSAPs, ports, services,
domains, workstations, windows, and gateways.
Subject. In event management, a device, process, or other named entity about which a
given event message has information.