User guide

22 DC 900-1303C

Freeway Client-Server Interface Control Document

description of the well-known port parameter, see the “Customizing System Installa-

tion” chapter in the Freeway User Guide.

The Freeway server uses the TSI logic and so expects the TSI-level packet exchanges that

occur between a client and the server. All packets exchanged between the client and the

server contain a TSI header, which indicates whether the packet is control information

or data. Control packets coordinate communication between the client and the server

TSI level. Data packets are processed at the MsgMux level for session control and ICP

data transfer.

The Freeway server design supports multiple sessions per connection. The client appli-

cation can open and maintain a number of Freeway sessions on one socket connection,

or open one session per connection. For client applications using the TSI, note that the

client TSI conﬁguration determines buffer size and resource management handled by

TSI. Therefore, you should take care when conﬁguring both the client and server TSI.

2.1.1 TSI Control Packets

A TSI control packet is a communication between a client and a server on the TSI level

to coordinate the use of the socket connection. TSI control packets are used after the

connection has been made to control the use of the socket. The packets are also used

just before the socket is disconnected to coordinate shutdown. A TSI control packet

consists of a TSI Header, and optionally, a TSI data area. The following sections describe

TSI control packets and provide examples of packet data ﬂow.

Bind

This is the ﬁrst packet that a client sends to the Freeway server after the socket connec-

tion has been established. The bind packet announces the communication capabilities

of the sender to the remote TSI application (this information is contained in the TSI

data area). Based on its TSI conﬁguration, the Freeway server can accept the bind

request by responding with an ACK packet, or it can reject it by responding with its own

Bind request packet. If the client receives an ACK packet from the server, the exchange