VTAM® and the application program share responsibility for implementing a type 6.2 LU.
VTAM is responsible
for the following actions:
- Providing a higher-level API that assists an application program in building an LU protocol boundary, as described in the LU 6.2 architecture. This protocol boundary, largely implemented through the APPCCMD macroinstruction, enables application programs to request LU 6.2 services.
- Associating network communication resources with the application program.
- Terminating LU 6.2 communication services with an application program's partners if the application program ends prematurely.
The application program is responsible for the following
actions:
- Implementing the LU 6.2 concept of transaction programs
- Using VTAM's APPCCMD macroinstruction to perform LU 6.2 functions
- Maintaining internal resources needed to support a type 6.2 LU
Figure 1 shows that VTAM and the application program share the responsibility for implementing a type 6.2 LU.
Figure 1. VTAM and application program implementation
responsibilities