POWER7 information

Starting a trace

The Work with Communications Traces display has a Start Trace function key that allows you to select options for tracing data.

On the Start Trace display, enter the name of a communications configuration object description at the Configuration object prompt:
  • For IBM® i operating systems:

    If you do not know the name of the configuration object, the work with configuration status (WRKCFGSTS) command allows you to view a list. You can view line, controller, or network information by entering the *LIN, *CTL, *NWI, or *NWS parameter.

    You can also use this command to vary off a line and all the I/O processors and devices under it.

Describe the trace in the Trace description field. This field can help you identify the trace.

You can select a buffer size to hold the communications data that the trace collects. The default buffer size is 1=128K bytes. Base the size of the buffer on the speed of the communications line and on the amount of time necessary to trace the data. For high-speed lines or long periods of tracing, use a larger buffer size.

If you specify Yes in the Stop on buffer full field, the trace stops when the buffer is full. This option is useful for viewing the initial data that is coming across a line. If you specify No, the trace continues until you stop it. In this case, the data in the buffer will be written over each time the buffer is full.

You can select the direction of data to be traced by specifying one of the three selections in the Data direction field:
  • Only data that the system is sending (option 1)
  • Only data that the system is receiving (option 2)
  • Both the data sent and received by the system (option 3)
Note: If you specify option 1 (Sent) for lines that are in SDLC short hold mode, the trace does not include controller names.

You can select how much data is traced in a frame of data. The value that is entered is the amount that is saved as part of the trace. The minimum value that is allowed for both the beginning and the end value is 36 bytes. Those 36-byte minimum values include the protocol header. The configuration object you are tracing determines the maximum value that is allowed.

Notes:
  1. The BSC protocol ignores the beginning and ending byte values.
  2. The SDLC, high-level data link control (HDLC), X.25, frame relay, Ethernet, distributed data interface (DDI), ATM, and token-ring protocols ignore the ending byte value.
  3. The minimum value that is allowed for the beginning byte value for local area network (LAN) protocols (including frame relay protocols and ATM protocols) is 72 bytes.

When all required options are complete, press Enter. The Work with Communications Trace display appears.

If the communications object being traced is in varied off status when you start the trace, the trace remains in waiting status until you vary the communications object on. If the object is varied on, the trace will immediately go to the active state, and the system will begin to collect trace data.

The trace remains active until one of the following occurs:
  • You select the option to stop the trace on the Work with Communications Traces display.
  • You vary off the configuration object being traced.
  • The configuration object being traced has an error.
  • The trace buffer is full, and the option to stop when the buffer was full was selected.
Note: While the trace is active, you can exit the communications trace function to do other work.

Traces are not automatically deleted when you exit a communications trace function. To return to the communications trace:

  1. Select the Start a service tool option from the service tools (SST or DST) display.
  2. Select the Work with communications traces option.
  3. From the Work with Communications Traces display, you can check the status of the trace or select to stop the trace.
Parent topic: Work with communications trace

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Last updated: Wed, September 28, 2016