Physical And Logical Unit Types; Physical Unit (Pu) Types And Examples; Summary Of Lu Types And Representative Ibm Products - IBM 6400 Setup Manual

Physical and Logical Unit Types

This section describes some of the Physical Unit (PU) types and Logical Unit
(LU) types that you are likely to use when configuring this printer on your
host system. Generally, the PU defines the type of communications
relationship that the HOST VTAM has with a communications controller
such as a 3174 control unit or a controller inside a printer such as a 3820 or
3935. Alternatively, it can describe the relationship that one host VTAM has
to another host VTAM or equivalent, such as an AS/400.

Physical Unit (PU) types and examples

Physical Units, as implied, are part of the physical hardware such as a control
unit (3174). VTAM and NCP use various PU types in conjunction with the
Logical Unit (LU) types to define the device and logical session to be
established with an SNA network.
PU type 2
The PU type 2 is the physical unit type that is required for an LU type 0, type
1, or type 3 (see LU type description following). Examples of PU type 2 are
3174 control units.
PU type 2.1
The PU type 2.1 is the physical unit type that is required for an LU 6.2 (see
LU type description following). Examples of PU type 2.1 is an IBM 3820,
IBM 3935, or PSF/2.

Summary of LU Types and Representative IBM Products

Listed below are the LU types that SNA currently defines and the kind of
configuration or application that each type represents. Also mentioned are
hardware or software products that typically use each type of logical unit. A
logical unit (LU) describes the type of relationship that the Host VTAM and
applications have with a specific device such as a printer. This relationship
determines the commands supported from the host to the device and the type
of feedback the device gives to the host.
D–18 6400 Line Matrix Printers Setup Guide, Cabinet and Pedestal Models