Patterns: Implementing Self-Service in an SOA Environment

Chapter 12. J2EE Connector Architecture scenario 433

12.5 Runtime guidelines for JCA applications

In this section we discuss some of the more pertinent points about the runtime

configuration of WebSphere Application Server V6, CICS Transaction Gateway

6.0. and IBM CICS required for the ITSOMart application.

Configuring the runtime requires the following actions:

򐂰 Install and configure the local CICS Transaction Gateway.

򐂰 Install and configure the CICS ECI resource adapter on WebSphere

Application Server.

򐂰 Configure WebSphere Application Server and the service integration bus.

This process assumes that the CICS Transaction Server and CICS application

are up and running.

12.5.1 CICS Transaction Gateway

There are three typical CICS Transaction Gateway runtime configurations for the

ITSOMart application:

򐂰 Local CICS Transaction Gateway

򐂰 Remote CICS Transaction Gateway

򐂰 Remote CICS Transaction Gateway on z/OS

The ITSOMart scenario uses a remote CICS Transaction Gateway running on a

distributed platform. It connects to the CICS server using TCP.

Local CICS Transaction Gateway

When designing a solution that includes CICS Transaction Gateway and

WebSphere Application Server, there are several topologies to consider.

Figure 12-25 on page 434 illustrates the use of a local connection between the

application running in WebSphere Application Server and CICS Transaction

Gateway. The CICS Transaction Gateway resides on the same machine as

WebSphere Application Server. The application is using the CICSECI resource

adapter.

In local mode the CICS Transaction Gateway Java code is loaded into the

application server JVM. The client daemon is invoked through the CICS

Transaction Gateway JNI layer. The client daemon then invokes an

enterprise-tier CICS program using ECI calls. The underlying protocols that the

ECI call uses to invoke CICS applications are TCP/IP, APPC, or TCP62 (APPC

over TCP/IP protocol). The ECI call can be routed to any CICS server.

434 Patterns: Implementing Self-Service in an SOA Environment

Figure 12-25 Local CICS Transaction Gateway

Remote CICS Transaction Gateway

In a remote topology (Figure 12-26), WebSphere Application Server and CICS

Transaction Gateway reside on separate machines and use TCP/IP for

communication. A gateway daemon on the CICS Transaction Gateway machine

provides the interface to the WebSphere Application Server and the client

daemon.

Figure 12-26 Remote CICS Transaction Gateway

This is the topology used in the sample ITSOMart application.

Remote CICS Transaction Gateway on z/OS

Another common topology, shown in Figure 12-27 on page 435, features a

remote CICS Transaction Gateway on z/OS. A transaction is invoked from a

distributed environment remotely using the TCP protocol. The protocol between

an application server and a CICS Transaction Gateway can be either TCP or

SSL. The CICS Transaction Gateway invokes a CICS enterprise-tier program

using the External CICS Interface (EXCI). EXCI is an interface that allows a z/OS

JNI

CICS

Transaction

Gateway

Client

Daemon

CICS

Server

CICSECI

Resource

Adapter

WebSphere Application

Server

EJB

CCI

APPC

TCP62

TCP/IP

Distributed platform

TCP

CICS Transaction

Gateway

JNI

Client Daemon

CICS

Server

CICSECI

Resource

Adapter

WebSphere Application

Server

EJB

CCI

Distributed platform

SNA

TCP62

TCP/IP

Gateway

Daemon

Distributed platform