Troubleshooting data for intersystem communication (ISC) problems

CICS® MustGather for intersystem communication (ISC) problems

Gather the following diagnostic information before contacting the CICS support team to troubleshoot your intersystem communication (ISC) problems.

Required data:
  1. The CICS message log for any DFHZCnnnn message. If you have problems with connecting or have a failure when you run a transaction, the console and CSNE transient data queue usually have messages. If the other region is also CICS, make sure that you have the message log from that region too. For more information on DFHZCnnnn messages, see CICS messages.
  2. The MVS™ system dump that is taken at the point of failure. For more information, see Using dumps for CICS problem determination on z/OS®. If you cannot re-create the problem, take a dump by using the MVS dump command, or add the pertinent DFHZCxxxx message to the CICS dump table. If you cannot determine which side of the ISC connection causes the problem, dump both regions.
  3. The CICS internal trace, which runs within CICS regions that participate in the conversation. Ensure that the internal trace table size is big enough to contain sufficient data for diagnosis; for example, you can use a table size of 20480K. Also, turn on standard level 1 tracing for all components and level 1-2 for the TC component. Use the CETR transaction to turn on internal trace, set internal trace size, and set component trace levels. For more information, see Using trace for CICS problem determination on z/OS..
Optional data:
  1. If you can re-create the problem, the CICS auxiliary trace might be useful. Ensure that you run the trace on all the CICS regions that are involved in the ISC problem.
  2. If you want to see all of the trace entries in one file, you can use the GTF Trace. The GTF Trace is useful when the CICS regions are on different MVS regions. You can write the trace to a GTF trace data set on each MVS, and then merge the files to see the flow of trace in the connected regions. If the CICS regions are in a single MVS, you can write all the trace to a single GTF trace data set.
  3. The CICS transaction dump that is taken at the point of failure.
  4. The z/OS Communications Server exit tracing (CICS VTAM® exit tracing) that is written to the GTF trace data set. To get this tracing, GTF tracing must be active. Each VTAM exit in CICS contains a trace point that captures the relevant terminal control information. This tracing is often used instead of a VTAM buffer trace.
  5. The z/OS Communications Server (VTAM) buffer trace that allows you to look at all the data that is passed across a VTAM connection. You can use this trace if you are concerned with the data stream being passed between the regions.