openUTM can communicate with CICS, IMS and TXSeries partner applications via the SNA protocols LU6.1 and LU6.2. The LU6.2 protocol should always be used for new links.
openUTM-LU62 is also required to communicate via LU6.2. openUTM-LU62 is an OSI TP partner from UTM’s point of view and an LU6.2 partner from CICS or IMS point of view. With this type of link the partners can work with or without global transaction management.
Refer to the following diagram for the most important types of links.
Figure 21: Connecting openUTM to IBM transaction monitors
No additional software is required in the IBM host, the SNA connection is created by the openUTM-LU62 transport system together with the platform-specific components SNAP-IX or IBM Communications Server. If openUTM runs on Unix, Linux a Window system openUTM-LU62 and SNAP-IX or IBM Communications Server can also be installed on this system, and the system can be connected directly to the SNA network.
Job submitter and job receiver
A UTM application can contain job-submitting services as well as job-receiving services when connected to CICS or IMS.
These two roles do not have the same authorizations in openUTM, i.e. certain rules apply to the job-submitting and job-receiving services when a global transaction is terminated. These rules must be observed by the CICS and IMS application programs, even if the programs allow a different procedure to be used when this occurs.
openUTM as the job submitter
A UTM job-submitting service addresses a CICS or IMS job-receiving service exactly like it does a UTM job-receiving service. openUTM can submit dialog jobs as well as asynchronous jobs (message queuing).
CICS as the job submitter
CICS can start dialog services as well as asynchronous services in openUTM.
IMS as the job submitter
The possibilities depend on the type of connection in this case:
For LU6.2 interconnection, IMS can start dialog services as well as asynchronous services in openUTM.
For LU6.1 interconnection, on the other hand, IMS can only start asynchronous services in openUTM. In order to allow IMS to open dialogs in spite of this, LU6.1 provides the ability to create dummy dialogs between asynchronous services. A dummy dialog returns additional information to the job submitter that can be used by the job receiver to send the reply back to the correct partner. openUTM contains a special extension of the program interface specifically for this purpose.
Dummy dialogs are not possible in conjunction with CICS partners.
| You will find a detailed description of how to generate and program connections with CICS and IMS in the manual “Distributed Transaction Processing between openUTM and CICS, IMS and LU6.2 Applications”. |
