-C H A P T E R

C H A P T E R 1

Introduction to Sun 3270 Pathway

This chapter contains the following topics:

Sun 3270 Pathway Overview

Supported Transport Protocols

Sun 3270 Pathway Overview

Sun 3270 Pathway is the collective name for a suite of programs that can communicate to a 3270 end-system. The core of the components is the 3270 Pathway Bean, a Java component that enables a developer to:

Develop an application that connects to a 3270 end-system

Run an application on that end-system

Extract data from that application.

Because the Sun 3270 Pathway Bean conforms to the Java Bean standards, you can use it to integrate it into many of the available Java integrated development environments (IDEs) that support Java Beans, such as Sun ONE Studio. You can also use a Java Development Kit (JDK) to produce applications that use Sun 3270 Pathway.

The following components are shipped with Sun 3270 Pathway:

The Sun 3270 Pathway Bean (see Chapter 4)

The 3270 Pathway Navigation Recorder tool (see Chapter 7)

A TCP Router (see Chapter 10)

The Pathway Terminal (see Chapter 11)

Supported Transport Protocols

Sun 3270 Pathway supports the Telnet 3270 (TN3270) transport protocol. This means that your 3270 host must be available through a TN3270 server so that the Sun 3270 Pathway Bean can connect to it.

The Sun 3270 Pathway supports both types of TN3270:

Basic TN3270

TN3270E (conforms to RFC 1647 and RFC 2355)

Sun 3270 Pathway is designed as a TN3270 client and primarily deals with 3270 datastreams. However, it can also deal with non-3270 datastreams during the following circumstances:

When using the TN3270E protocol, the server is permitted to send raw Telnet data; therefore, the terminal must act in a non-3270 manner.

When a server has a non-3270 routing front-end program, which sends and receives non-3270 datastreams.

When Sun 3270 Pathway is dealing with these non-3270 datastreams, it is deemed a network virtual terminal (NVT). While the datastreams are completely hidden from the programmer, some methods are not available when in NVT mode.

The majority of applications do not need to allow for this mode of operation because they communicate exclusively in 3270 mode.

Caution - Data flows from the terminal to the server (and vice versa) are in plain text over a TCP/IP connection. This means that all data (including passwords) flow in an insecure manner.