Running the SIT, TIC internal trace, and CSS adapter trace

Start SIT from the host processor.

The ACTTRACE PIU for the SIT activates the TIC internal trace. When NTRI receives a DACTTRACE PIU to deactivate SIT, it deactivates the TIC internal trace.

The TIC internal trace is not deactivated in case of discontact (CLOSE) or deactlink SNA commands, but is deactivated in case of slowdown.

For CSS adapter trace, after a CSS adapter trace is started on a trace point, a second adapter trace cannot be started even if the request is for a different trace point. If running a CSS trace on a logical line, the logical line must be active.

Restriction: NCP does not support SIT for communication lines that are driven by user-written line-control code, unless the UACBs are compatible with NCP's ACBs. The request to start or stop SIT is passed to the user-written I/O code. At that point, user-written code must support the trace. NCP handles line trace requests for user-written line control if it is compatible and COMPACB=YES is specified on the GROUP definition statement.

You can activate VTAM® traces when VTAM is started or as needed. Use the TRACE option on the START command to begin the trace when VTAM is started. Use the MODIFY TRACE command to begin the trace when VTAM is already running. The TRACE start option and the MODIFY TRACE command have additional parameters that are unique to the type of trace.

For more information about SIT, the TRACE start option, and the MODIFY TRACE command, see z/OS Communications Server: SNA Operation. To interpret and print trace data, see ACF/TAP information in ACF/TAP and trace data.

Before you start SIT for VTAM, start the GTF trace with the USR option. For information about GTF, see z/OS MVS Diagnosis: Tools and Service Aids.