SNAX/APC Configuration and Management Manual

Introduction
SNAX/APC Configuration and Management Manual—138787
1-7
Communication With SNAX/APC
Communication With SNAX/APC
TPs communicate with the SNAX/APC system through the Tandem file system by using
a message-oriented application program interface. The basic unit of communication is
an interprocess communication, or IPC, message. IPC messages contain Units of Work
(UOWs), which are defined in the SNAX/APC Application Programming Manual. The
TP sends information to SNAX/APC in an IPC message, and SNAX/APC returns
information in a reply. As shown in Figure 1-6
, the TP typically sends an IPC
containing a verb request to SNAX/APC, and SNAX/APC replies with an IPC
containing return codes and verb responses.
Acting as the LU (using the data flow control and transmission control layers of SNA as
shown in Figure 1-1), SNAX/APC assembles the requests from the TP and creates SNA
Request Units (RUs), which are sent to the Tandem SNA access method (typically
SNAX/XF). SNAX/XF sends these over the network (typically as SDLC frames) to the
target LU. Incoming traffic received by SNAX/XF is passed up to SNAX/APC which
decodes the SNA RUs into IPC messages to forward to the TP.
Further details on interprocess communication messages may be found in Section 2 of
the SNAX/APC Application Programming Manual.
SNAX/APC Product Overview
The SNAX/APC subsystem has the following components:
•
SNAX/APC process (APCOBJ)
•
SNAX/APC configuration interface to SCF
•
SNAX/APC Dispatcher
•
SNAX/APC Application Prototype Simulator (APS) system
•
SNAX/APC Trace Analysis Program (APCTAP)
Of these components, only the SNAX/APC process has been upgraded to run on the D-
series or G-series operating system. However, the other listed components can
communicate with D-series or G-series SNAX/APC processes and/or run properly in a
Figure 1-6. Communications Overview
006CDT .CDD
IPC Messages and Replies
SNA RUs
Transaction
Program
SNAX/APC
SNAX/XF