User guide

DC 900-1303C 21

Chapter

Freeway Client-Server

Protocol

The Freeway client and server communicate via TCP/IP BSD-style sockets. (The server-

resident client application that communicates via the shared-memory interface is not

discussed in this document). The Freeway server acts as a TCP/IP socket server. It issues

listen() call for accepting incoming connections from the Freeway client. The Free-

way client then issues the

connect() call to request a connection to the Freeway server.

The socket library calls needed for socket connection, disconnection, and data transfer

are beyond the scope of this document and it is assumed that you are familiar with

them. You may want to refer to the user guides or man pages for your operating envi-

ronment. This chapter discusses the format of data packets that are passed between the

Freeway client and the Freeway server, and the data packet sequence necessary to estab-

lish and maintain Freeway sessions.

2.1 Freeway Packet Protocol

If are using the TSI, you do not need to read “TSI Control Packets” (Section 2.1.1), but

you do need to read “TSI Data Packets” (Section 2.1.2) to familiarize yourself with the

packets and their header structures. If you are not using the TSI, you should read both

of these sections because you need a detailed knowledge of the sequence of packet

exchanges between the client and server.

Use a text editor to examine the contents of the server TSI conﬁguration ﬁle and obtain

the number of the well-known port on which the Freeway server is listening. The client

application uses this port number when requesting connection to the server. For a