Introduction to SNAplus2

SNAplus2 Resources

Session Resources

The following session resources are used by SNAplus2:

•Logical units (see “Logical Units”)

•Modes and their associated classes of service (see “Modes and Classes of Service”)

•Directory information (see “Directory Information”)

Logical Units

An LU is the node's point of contact with a user program (3270 emulation program, RJE workstation, APPC TP, CPI-C application, or LUA application). LUs are divided into two categories:

Dependent LUs

Type 0–3 LUs are referred to as dependent LUs; they can support only one user session at a time, and a session is controlled by the host program. Type 6.2 LUs can also be dependent LUs if they are used to communicate with host computers running older versions of SNA host software.

LU types 0–3 are sometimes referred to as “old LUs,” and are used to communicate with hosts using 3270 emulation, RJE,or LUA.

Type 0–3 LUs can also be grouped into LU pools, as described in “LU Pools”. In addition, dependent type

6.2LUs can be assigned to default pools, as described in “Default LUs”.

Independent LUs

LU type 6.2 is used to communicate with either hosts or peer computers using APPC or CPI-C.

Type 6.2 LUs that are used to communicate with peer computers, or with newer SNA software on host computers, are referred to as independent LUs. Independent LUs can support multiple user sessions simultaneously.

Dynamic Definition of Dependent LUs. Dynamic definition of dependent LUs (DDDLU) is a host feature that enables dependent LUs on the SNA system to be added to the host configuration when the communication link from the SNA system to the host is established.

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Chapter 2