SNAX/APC Application Programming Manual

Using the Application Program Interface

SNAX/APC Application Programming Manual—138786

1-11

Establishing Communication With the Local LU

A local TP initiates communication with the SNAX/APC server by sending a TP-

READY request to it. There are three types of TP-READY requests:

•

LOCAL-ATTACH = Y (TP is the source TP)

The local TP initiates the conversation. Local attach means that the TP requests the

SNAX/APC server to initiate the SNA ATTACH request processing. In a TP-

READY request with Y in LOCAL-ATTACH, the TP indicates that it is requesting a

local attach and that the TP was not dispatched. The local TP begins the

conversation in Send state.

•

LOCAL-ATTACH = N (TP is the target TP)

The local TP waits for an ATTACH request from a remote TP.

•

A non-LOCAL request can indicate that local TP is waiting for an ATTACH request

to a specific local LU (specific TP-READY) or to any local LU (general TP-

READY).

•

DISPATCHED = Y (dispatched)

The local TP was started by the PATHMON process and received a DISPATCH-TP

request from the Dispatcher. In a dispatched-type TP-READY request, SNAX/APC

has already received a remote attach for this TP. The local TP begins the

conversation in Receive state.

The following subsections illustrate these actions in three detailed examples: local

source, local target, and dispatched request.

Initial Environment

The three examples use the same basic configuration, shown in Figure 1-1. The Tandem

system is connected to an IBM host in an SNA network. An application (TP) is running

on the Tandem system. A CICS application is running in the host system.

Note. The IPC message containing the TP-READY request must contain only the TP-

READY request; it cannot contain other UOWs.