SNAX/HLS Application Programming Manual

Glossary
104707 Tandem Computers Incorporated Glossary–7
secondary logical unit (SLU). One of the two LUs involved in a LU-LU session. The SLU
functions under the control of the remote PLU. It accepts an incoming BIND request
from the PLU.
session. In SNA, a temporary logical connection between two NAUs for the purpose of
exchanging data and control information in accordance with ground rules that have
been agreed upon for that exchange. A session can be activated, tailored to provide
various protocols, and deactivated, as requested.
session passthrough. A SNAX/XF feature that allows the SNA host to control SNA
devices on Tandem NonStop systems as if they were directly connected to the host.
site update tape (SUT). The means by which Tandem software is distributed to all user
sites.
SLU. See secondary logical unit.
SNA. Systems network architecture.
SNA node types. The four network node types defined by SNA are: node type 5 (a
host), node type 4 (a communications controller), node type 2 (a cluster controller),
and node type 1 (a terminal controller).
SNAX/CDF. See Systems Network Architecture Communications Services/Cross
Domain Facility.
SNAX/High level services (HLS). An interface application that allows Tandem application
programs to communicate with SNA devices and host software. SNAX/HLS enables
Tandem programmers who are not familiar with IBM’s System Network Architecture
(SNA) to develop applications for the SNA environment. SNAX/HLS includes fast
prototyping (Application Prototyping and Simulation or APS), operational control
(HLSCOM), and troubleshooting (HLSTAP) tools.
SNAX/XF. See Systems Network Architecture Communications Services/Extended
Facility.
SNAXLink. A Tandem product comprised of both hardware and software that provides
a direct channel link between a Tandem system and several types of IBM systems.
SNAXLink can also be used with IBM channel–compatible systems that contain VTAM
and SNA support.
SNALU. A SNAX/XF and SNAX/CDF interface that provides the functions of the
lower two SNA layers (data link control and path control) and some functions of the
transmission control layer.
SPI. Subsystem Programmatic Interface. SPI is the interface that HLSCOM uses to
communicate with SNAX/HLS. SPI is part of Tandem’s Distributed Systems
Management software.
SSCP. See system services control point.
SSCP–LU session. In SNA, a session between an SSCP and a LU that enables the LU to
request the SSCP to help initiate LU–LU sessions.