TXSeries has long existed now for close to 20 years and been there as a distributed CICS environment all the while supporting a subset of CICS on z/OS features and primarily intended for co-deployment with CICS TS – encouraging lower end workload running on TXSeries integrating with business critical applications deployed on CICS on zSeries.
More recently, customers or users have been interested in front ending most of their applications with a web based client, moving over from the traditional 3270 way of representing their screens. So, how is it that users can get the eventual connectivity of their web applications over into the business logic (possibly written in COBOL or C) running on TXSeries.
For customers working with web applications and having business logic in COBOL, with existing options, customers can use IBM WebSphere Application Server (WAS) and connect to IBM TXSeries through CICS Transaction Gateway (CTG). Typically, a connection across WAS – CTG – TXSeries looks like below,
Servlets, EJBs or JSPs written or hosted in WAS can connect to CTG using JCA with the help of CICS ECI Adapter and CTG makes calls into TXSeries using the ECI – External Call Interface. As you can see through the figure, the TXSeries CICS region in turn provides connectivity to a DB2 data base or an MQ queue or other services depending on the need. Ideal deployment in TXSeries these days includes an extension to the above picture, with a CICS on z/OS region on the extreme right.
This is a pure one-way or in bound connectivity from WAS over into business logic written in TXSeries CICS. WAS, CTG and TXSeries are three different products and all need to be configured and managed separately. None of these are part of the same logical unit, although using last participant support, you could get the TXSeries region to participate in a two-phase commit co-ordinated by a WAS instance.