HP UX SNAplus2 manual LU 2 for 3270 displays

SNA Terms and Concepts

Basic SNA Concepts

For example, LU 3 can support an application program running under Customer Information Control System (CICS) and sending data to an IBM 3262 printer attached to an IBM 3174 Establishment Controller.

LU 2 (for 3270 displays)

LU 2 supports application programs and display workstations communicating in an interactive environment using the SNA 3270 data stream. Type 2 LUs also use the SNA 3270 data stream for file transfer.

For example, the LU 2 protocol can support 3270 emulation programs, which enable workstations to perform the functions of IBM 3270-family terminals. In addition, LU 2 is used by other programs to communicate with host applications that normally provide output to 3270 display devices. Such TPs enable the workstation to achieve a form of cooperative processing with the host.

LU 1 (for 3270 printing and RJE)

LU 1 supports application programs and single- or multiple-device data processing workstations communicating in an interactive, batch-data transfer, or distributed data processing environment. The data streams used by LU type 1 conform to the SNA character string or Document Content Architecture (DCA).

For example, LU type 1 can support an application program running under Information Management System/Virtual Storage (IMS/VS) and communicating with an IBM 8100 Information System. This enables a workstation operator to correct a database that the application program maintains.

Applications that use LU 1 are often described as remote job entry (RJE) applications.

LU 0 (for LUA)

LU 0, an early LU definition, supports primitive program-to-program communication. Certain host database systems, such as IMS/VS (Information Management System/Virtual Storage) and some point-of-sale systems for the retail and banking industries (such as the IBM 4680 Store System

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