gtpd2m0rData Communications Services Reference

Overview of the Unsolicited Message Processor

The Control Program routing support includes this program package to send unsolicited messages to any non-SNA terminal or SNA logical unit attached to a host TPF system. For purposes of this document, a SNA LU will be either a 3270 SDLC terminal logged on to a non-SNA application or an NEF (terminal attached via the NETWORK EXTENSION FACILITY ) LU. NEF is part of the ACF support which provides connection between 6 bi ALC (Airlines Line Control) terminals and NCP. SNA terminals (such as 3600s) that do not have an LNIATA are specifically excluded from receiving unsolicited messages. This is because they may only log on to SNA applications for which unsolicited messages are not supported. This is because the TPF system is not in control or aware of the screen format and may not send data which would jeopardize the integrity of the application's input message format. Messages originate at the CRAS terminal set or within any processor attached to a TPF network. Processors may consist of SCP, the TPF system, or ACF.

The unsolicited message processor consists of a number of program segments and two data records: unsolicited message directory record (CO1DR) and unsolicited message notification list (CO3NL)).

Purpose

This package is designed to process CRAS and host processor requests to send an unsolicited message. The requests are identified by information in the input message, a parameter list, and the message header. The routing may be to a specific terminal (single message) or to a group of terminals or SNA logical units (broadcast message).

The terminal types supported by the TPF system and ACF have varying characteristics which require complex formatting and procedural support. This package minimizes the formatting and procedural variances while using the TPF system and ACF resources available with the Message Router.

Options

User application programs may send an unsolicited message to either a single non-SNA terminal/SNA LU or to all non-SNA terminals/SNA LUs assigned to the originating application. The message may be sent to any terminal type with the exception of R/O (receive only printers) devices.

Messages sent to an R/O device via a ROUTC macro are passed by the Message Router directly to the Long Message Transmitter Program or Output Message Transmission Program in the case of SNA messages.

Unsolicited messages may be sent via the following Z-type messages: ZSNDU and ZSNDA. For more information about the message routing commands, see TPF Operations.