If MVS/APPC is running and the LU is not defined as LU=OWN, VTAM® traces the input/ output buffers
to see what is being exchanged between the source and target servers.
GTF trace, an MVS facility, is used by VTAM to
collect trace records. The VTAM trace
can show buffer contents. VTAM trace
can also show SNA request and response information. The following
information shows VTAM commands
and functions:
- Turn on the GTF trace facility:
- S GTF.IT
- R xx, TRACE=RNIO,USR
- R xx U
When the GTF initialization is complete, GTF tells you the name
of the trace data set in message AHL906I.
- Find the VTAM LU to trace:
- D APPC,LU,ALL
The LU in use is shown (for example, LLUN=MF1AP001)
- Find the name of the VTAM procedure:
- D A,L
In the next example, the VTAM procedure
is called "VTAM2".
- Start the VTAM procedure
by tracing the APPC LU:
- F VTAM2,TRACE,ID=MF1AP001,TYPE=BUF
In order to view the trace records, you must stop the GTF trace.
- Format the trace under IPCS by using the following command with
the GTF trace data set named as target.
- GTFTRACE RNIO SLIP SVC USR JOBNAME(GDEDFM APPC)