User guide

DC 900-1303C 13
Chapter
1
Overview
This document describes Simpact’s client/server interface to the Freeway communica-
tions server. It’s primary purpose is to serve as a reference tool when you are writing
client applications that do not use the data link interface (DLI).
Note
Two types of client applications are discussed in this document:
ones that use the transport subsystem interface (TSI) and ones
that do not. In either case, it is assumed that the applications do
not use the data link interface (DLI). That is, applications that use
the DLI are not discussed.
If your client applications use the TSI, you need to use this document to determine how
each packet is constructed when communicating with the TSI. If your client applica-
tions do not use the TSI, you need to use this document to determine the sequence and
construction of every exchange between the Freeway server and client.
A TSI layer resides on both the Freeway server and client. If your client applications do
not use the TSI, they must perform the work that is normally done by the client TSI
layer, including all buffer management. However, bypassing the TSI gives the applica-
tions complete control of how data is written and read once sessions have been estab-
lished with the server.