CTCP input data message processing

The CTCP receives both commands and data from NPSI for virtual circuits defined for LLC4 (GATE) support. For this dialog, it is assumed that the NPSI/GATE support is further defined to have Fast Connect (FC) capability, resulting in both data messages and NPSI command messages flowing on the same virtual circuit to the host. The first text character in each message indicates whether it is a NPSI command or a data message.

In the following sections, the CTCP is assumed to be defined via a MSGRTA statement as a z/TPF application named CTCP. z/TPF creates an associated RVT definition of a z/TPF Primary LU resource named CTCP. The CTCP functions are handled by a PSV routine (one or more ECB controlled programs) named GATE1. GATE1 is specified as the PSV on the OSTG RSC statement for each NPSI LU (both MCH_LU and VC_LU) defined to z/TPF which are in session with the CTCP PLU. It is further assumed that the sessions between the CTCP and the NPSI LU resources (both MCH_LU and necessary VC_LU resources) have been established prior to any NPSI command flows, and that although the PIU received is directed to the CTCP PLU, all data messages are ultimately destined for a z/TPF application named 'APPL'.

This section describes the input-related flow and control blocks for inbound data messages flowing through your CTCP Process. This material is divided into two parts: data flow for soft copy and hard copy devices.