Using IBM Application Development Tools for z/OS and OS/390

150 Using IBM Application Development Tools for z/OS and OS/390

4.2 System configuration

The following SNA terms will be used in this chapter:

򐂰 Logical unit (LU): This is a port through which an end user accesses an SNA network to

communicate with another end user or the system services control point (SSCP).

򐂰 Transaction program (TP): In WSim, this is any program using LU6.2 communications

protocols to communicate with another program. WSim implements TPs using CPI-C.

򐂰 Session: A session is a logical connection enabling two network addressable units to

communicate with each other, such as an LU-LU, or an SSCP-LU session. Each half of a

session is a half-session.

Both the network to be simulated and the system to be used to run WSim must be configured

before testing. The configuration of the network containing the resources to be simulated by

WSim and the real system to be tested (

the system under test) is known as the logical

configuration

. For each logical configuration, a specific physical configuration must be used,

which is the configuration of the real system used to run WSim. Resources of a physical

configuration include a host processor, system software, application software, WSim, etc.

4.2.1 Physical configurations

WSim can operate in either one of two basic physical configurations:

򐂰 VTAM and CPI-C application configuration:

Used to simulate LUs in the same subarea as VTAM. LUs can have a session with any

other LU that VTAM will allow it to start with. It is also used to simulate client and server

CPI-C TPs in the same subarea as VTAM. TPs can have a conversation with any other TP

on any LU to which VTAM will allow a conversation to be started.

This physical configuration contains WSim, VTAM, and VTAM applications or TPs under

test. WSim runs as a VTAM application program.

򐂰 TCP/IP application configuration:

Used to simulate Telnet 3270, 3270E, 5250, NVT, and FTP clients. These clients can

have a session with any Telnet 3270, 3270E, 5250, NVT, or FTP server that TCP/IP

allows. This configuration can also be used to simulate Simple TCP or UDP clients in

session with various servers.

This physical configuration contains WSim, TCP/IP, and TCP/IP applications under test.

WSim runs as a TCP/IP application program.

4.2.2 Logical configurations

WSim can operate in one of three basic logical configurations:

򐂰 VTAM application configuration:

Used to simulate SNA LUs accessing VTAM applications. LUs could be terminals or other

VTAM applications.

This logical configuration contains VTAM, VTAM applications, and VTAM applications and

LUs simulated by WSim.

򐂰 CPI-C application configuration:

Used to simulate CPI-C client (allocates outbound conversations but does not accept

inbound ones) TPs to test server (accepts inbound conversations) CPI-C TPs and network

resources or to simulate server CPI-C TPs to test client prototypes.