ACSE/Presentation and ROSE Interface Programmer's Guide

Chapter 3 37

Using ACSE/Presentation

Step 2: Establish an Association

Process A calls ap_set_env() using the AP_CNTX_NAME attribute to

identify the application context name. Process A then calls ap_set_env()

using the AP_PCDL attribute to propose transfer syntaxes for each

proposed abstract syntax that will be used for data transfer between

Process A and B.

Figure 3-5 Establish Data Transfer Environment

Request the Association

Process ap_snd() uses the A_ASSOC_REQ primitive and includes the

application context name, presentation context deﬁnition list (PCDL),

and Process B's presentation address. Process B uses ap_poll() to listen

for the association request. (See Figure 3-6.)

This can be used to limit the time Process B can wait for an association

request.

Communication

Endpoint A

Endpoint B

Process A Process B

AP Environment A

AP Environment B

ap_set_env()

AP_REM_PADDR,

b_p_sel,

b_s_sel,

b_t_sel,

b_nsap

AP_CNTX_NAME,a_cntx

AP_PCDL,a_pcdl

Initiator

Responder