Introduction to SNA Capabilities of Tandem NonStop Systems

Introduction to SNA Capabilities of Tandem NonStop Systems–134597
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Applications
This section describes how applications can communicate across the SNAX access
methods—the SNAX application programming interfaces (APIs), off-the-shelf
applications, and applications that you develop. This discussion requires introduction of
the following terms:
logical unit (LU). The software components that provide end users, including
applications, with access to an SNA network.
LU-LU session. An end-to-end logical connection between LUs.
LU-LU session type. In SNA, a classification of LU-LU sessions in terms of the
specific subset of SNA protocols and options supported by the LUs for that session:
LU type. The classification of a logical unit in terms of the specific subset of SNA
protocols and options it supports for a given session. The LU type corresponds to the
LU-LU session type it supports.
LU-LU
Session Type Description
0 A session using some SNA protocols and some user-defined protocols
1 A session between an application and single-device or multiple-device data
processing terminals, using the SNA character string data stream
2 An interactive session between an application and a single display terminal
using the SNA 3270 data stream
3 A session between an application and a single printer using the SNA 3270
data stream
4 A session, using SNA character string data stream, between (1) an
application and single-device or multiple-device data processing or word
processing terminals or (2) logical units in peripheral nodes.
6.2 A session between applications in peer systems, using the SNA general data
stream
7 An interactive session between an application and a single display terminal
using the 5250 data stream