OpenFlow trace display

This troubleshooting tool logs OpenFlow conversations captured in messages to and from the controller and the OpenFlow devices it manages.

You can export the captured messages in the trace log to a CSV (Comma-Separated Values) file that can be opened by applications such as Excel that are designed to accommodate this file type. This enables you to create a filter to display only the messages from the specific data paths you want to examine.

About the trace log

The number of events that can be held in the trace log is limited by system memory. For this reason, HP recommends that you export to a remote storage location any trace log content you want to retain, and to clear the controller trace log whenever its content is not needed on the controller itself.

OpenFlow trace display details

Screen componentDescription
Start trace icon

Starts trace logging.

In the default configuration, the trace stops after ten seconds have passed. (To change the trace interval, see “Changing the OpenFlow trace interval ”.)

Stop trace icon

Stops trace logging before the end of the configured trace interval.

Trace logging stops automatically at the end of the configured trace interval.

Multiple consecutive traces can be held in the trace log. To add additional trace results, start another trace.

Clear trace screen icon

Clears (resets) the current trace log.

To preserve the contents of the trace log before clearing it, see “Exporting the OpenFlow trace log”.

magnifying glass icon

Displays details of the selected trace event.


Copies the trace log into a CSV (comma-separated values) file. See see “Exporting the OpenFlow trace log”.


The time the message event was generated.


The event type. For example:


Indicates a check point in the trace log, such as the starting or stopping of a trace operation.


Indicates an OpenFlow message recieved by the controller (from a datapath).


Indicates an OpenFlow message sent from the controller (to a datapath).


The DPID (data path ID) of the data path associated with the event.


The trace message.

Starting, stopping, or clearing OpenFlow trace

Use the buttons above the Time field to control trace operations (see “OpenFlow trace display details”).

Displaying trace event details

  1. Select the event you want to examine.

  2. Click . Alternatively, double-click on the event.

    The Event Detail dialog box is displayed.

    Displaying event details

    Displaying event details

  3. To close the Event Detail window, click Close.

Exporting the OpenFlow trace log

Exporting an OpenFlow Trace Log places the trace content in a CSV file that is stored in the default downloads folder specified in your web browser settings.

For more information about CSV files, see RFC 4180.

NOTE: This section shows how to export and access OpenFlow Trace Log files using Google Chrome. You might experience different results than shown here, depending on your web browser and its configuration.

  1. Click Export. This action places the trace log contents into a CSV file in the default downloads folder in the system on which the controller is running. Check your web browser for an indication that the file has been created.

  2. To display and filter the CSV file content, see “Filtering the OpenFlow trace log in a CSV file”.

Filtering the OpenFlow trace log in a CSV file

  1. Open the CSV file in the default folder. For example, using Google Chrome, open the menu adjacent to the file name (of-trace.csv) and select Show in folder.

    Accessing the stored CSV file

    of-trace.csv in download menu

    In the resulting folder listing, locate the of-trace.csv file and open it using an application, such as Excel, that enables you to read the log messages and configure a filter. For example, to investigate the messages collected for data path

  2. Select the DPID (Data Path ID) column.

    DPID column

    DPID column

  3. Set the filter.

    Setting the filter

    Setting the filter

  4. Apply the filter by checking the box for data path

    Applying the filter

    Applying the filter

  5. In the resulting display, only the data filtered to data path 00:00:00:00:00:00:00:02 appears.

    Filtered trace log

    Filtered trace log

Changing the OpenFlow trace interval

The default trace interval is ten seconds. To change the interval:

  1. From the navigation menu, select Configurations.

  2. Open the com.hp.sdn.ctl.of.impl.TraceManager component.

  3. Click Modify.

  4. In the Value field, enter the desired duration in seconds for active trace recording. 10–60 seconds only.

  5. Click Apply to set the new time span for active trace recording, and return to the OpenFlow Trace view.