# Running Port Loopback Tests

The port loopback tests verify correct port operation by sending a frame out through the loop, and then verifying that the frame received matches the frame that was sent. Only one port can be tested at a time for each type of test.

Note: The Internal (SerDes) and External (SFP) level tests disrupt communication on the selected port. The Online (node-to-node) level test does not disrupt communication because the test requires that the port be online.

To run the Internal (SANbox2 and SANbox2-64), External (SANbox2 and SANbox2-64), or Online (SANbox, SANbox2 and SANbox2-64) port loopback test, do the following:

1. In the faceplate display, select the port to be tested.

2. Open the Port menu and select Port Loopback Test to open the Port Loopback Test dialog.

3. In the Test Selection area, choose the Internal, External, or Online radio button for the type of test to run.

Note: Internal and External tests are available only on SANbox2 and SANbox2-64.

* If you choose the Internal or External test, SANbox Manager will prompt you to confirm that the state of the port being tested needs to be changed to the Test (diagnostic) state in order to run the test. Click the OK button and SANbox Manager will change the port state. In the Port Loopback Test dialog, click the Start Test button to begin the test.

* If you choose the Online test (available on SANbox, SANbox2, and SANbox2-64), the fields in the Test Parameters area are activated. Enter the frame count, frame size, and choose a test pattern radio button. You may use the default pattern or enter a user-specified pattern (hex). Check the Terminate Test Upon Error box if you want the test to stop when encountering an error. Click the Start Test button to begin the test.

4. The Test Results area displays the test status, number of frames sent, and number of errors found.

5. To test another port, open the Select Port pull-down menu and select another port (number) and test type (Internal, External, or Online) radio button in the Test Selection area.

6. Click the Start Test button to begin the next test. Observe the results in the Test Results area.