IBM CICS Transaction Gateway has been proven over many years to provide high-performing, security-rich and scalable J2EE standards based access to CICS Transaction Server for z/OS, requiring minimal changes to CICS systems and usually no changes to existing CICS applications. Reusing these applications in mixed CICS and WebSphere workloads helps reduce cost, risk and time to market of new applications.
With IBM CICS Transaction Gateway for z/OS, Version 6.1, you can use your CICS communications area (COMMAREA)-based applications in comprehensive and sophisticated Java™ 2 Platform, Enterprise Edition (J2EE) and Web services solutions hosted on robust application servers, such as IBM WebSphere® Application Server.
CICS Transaction Gateway for z/OS, Version 6.1 delivers significant enhancements over previous releases, in two key value areas:
- Complete transactional two-phase commit integrity between distributed WebSphere applications and CICS applications running on z/OS
- Four major reliability, availability and serviceability enhancements to TCP/IP networking
Maximum transactional integrity
A global two-phase commit transaction helps ensure that data integrity is maintained when updating multiple resource managers in a distributed transaction. This capability helps ensure that the entire transaction can commit successfully, or if some error condition occurs, be entirely returned to the pre-transaction state. With global two-phase commit you can physically distribute a composite transaction across heterogeneous servers and operating environments - giving you maximum flexibility without compromising on data integrity.
Distributed global transactional integrity is provided through the provision of an XA-capable JCA resource adapter and the use of the z/OS Resource Recovery Services (RRS) subsystem. This feature enables CICS Transaction Server for z/OS to participate in two-phase commit transactions that are initiated in a J2EE, Version 1.4 application server, such as WebSphere Application Server, Version 6 on a distributed platform or on a remote z/OS system.
Two-phase commit transactions help ensure maximum transactional integrity by requiring a PREPARE command to be confirmed by each resource manager, before a COMMIT command makes all transaction changes permanent.
The full XAResource two-phase commit capability enables CICS Transaction Gateway to be able to fully participate in a global transaction, where units of work can be coordinated with other units of work going to different resource managers (such as DB/2, IMS, SAP, etc). Once a resource manager has responded positively to a prepare request, it enters a contract to commit the work as part of the transaction. This decision is persistent in RRS, so that even if the connection is lost or the CICS Transaction Gateway is restarted, the controlling transaction manager can recover and commit the work. The effect is that the entire global transaction now has better integrity.
Enhanced TCI/IP communications
CICS Transaction Gateway for z/OS V6.1 also provides four major enhancements to TCP/IP reliability, availability and serviceability:
- A load-balancing feature for XA transactions enables a group of gateways to act as one virtual endpoint for incoming TCP/IP requests, helping to maximize scalability and availability.
- An automatic TCP/IP subsystem reconnect feature enables new TCP/IP connections to be made to CICS Transaction Gateway after a restart of the TCP/IP subsystem. This enhancement helps improve availability and reduce the need for operator intervention.
- An IP address binding feature enables you to control which network interfaces can be used to connect to CICS Transaction Gateway, providing improved security and ease of network management.
- A connection timeout control feature provides the option to specify a timeout duration on pending socket connection requests, giving improved recovery in the TCP/IP network.
Comprehensive J2EE standards based solution
CICS Transaction Gateway for z/OS, Version 6.1 continues to support local-mode global transactions. This capability provides optimized two-phase commit support when WebSphere Application Server and CICS Transaction Server for z/OS are located on the same z/OS image. This configuration also provides the highest qualities of service as communication between the CICS and WebSphere servers is facilitated via shared memory rather than over a network protocol.
WebSphere Application Server Version 5 is also supported if deployed with the downloadable JCA, Version 1.0 resource adapter. Some functionality, such as two-phase commit, is not supported in this configuration due to restrictions in the previous version of the JCA specifications.
CICS Transaction Gateway, Version 6.1 is only available on z/OS. The latest level of CICS Transaction Gateway for Multiplatforms continues to be Version 6.0. This is because the new two-phase commit feature requires the z/OS-specific Resource Recovery Services (RRS) functionality. Both the z/OS and the multiplatform products continue as essential products in the IBM portfolio, with z/OS remaining as the flagship platform.
