Tips and Tricks: Steps to setup CICS Transaction Gateway(CTG)

Having recently worked on integrating across multiple CICS regions using CTG, I have shared some of my observations during configuration.To put things in perspective, below is a conceptual diagram to set up a high availability CTG environment.

Fig 1: Conceptual Diagram

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Before you start:

1.CICS Transaction Gateway should be installed.
2.You also need to install support pack CA1T V3.0.1.
3.Each CICS region needs to have dedicated IPIC enabled TCP/IP listener port.

Also note, a single instance of CTG cannot connect using a shared TCPIP port across multiple CICS regions. In order to establish a CTG connectivity, it needs a dedicated IPIC enabled port that the CICS region is configured to listen on. There seems to be a limitation on CTG to connect to multiple CICS regions with any available ports. Some of the available protocols on TCPIP ports are ECI,HTTP,IPIC.

Here are the steps:
Step 1:Make the following entries in the ctg.ini file
With the known CTG regions that you need to connect that has the dedicated IPIC ports, include the CTG configuration details in the format below
SECTION IPICSERVER = IPIC1
    HOSTNAME=Hostname / ip address
    PORT=IPIC PortNumber
ENDSECTION
SECTION IPICSERVER = IPIC2
    HOSTNAME=Hostname / ip address
    PORT= IPIC PortNumber
ENDSECTION

Step 2: Enable Load balancing feature. 
Load balancing(round-robin)is enabled by setting following property in CTG configuration file
cicsrequestexit=com.ibm.ctg.samples.ha.RoundRobinExit

Step 3:Next, set list of available IPIC connections to the load balancing pool. This will be part of ctg.ha.ini file.
CTG_LBG=IPIC1, IPIC2

Step 4:Finally, bind web service to load balancing group
SECTION WEBSERVICE=getmyaddress
URI=/getmyaddrdetails/v1
BINDFILE=~/home/apps/GET_CUST_ADDR_DETAILS/GET_CUST_ADDR_DETAILS.wsbind
SERVER= CTG_LBG
ENDSECTION

Reference:
https://www.ibm.com/support/knowledgecenter/en/SSZHFX_9.2.0/getting_started/topics/configuring.html