5 – Managing PortsTesting Ports59097-02 B 5-17A5.5Testing PortsThe port loopback tests verify correct port operation by sending a frame outthrough the loop, and then verifying that the frame received matches the framethat was sent. Only one port can be tested at a time for each type of test. The PortLoopback Test dialog shown in Figure 5-4 presents the following loopback tests:Figure 5-4. Port Loopback Test Dialog SerDes level (Internal) - The SerDes level test verifies port circuitry. TheSerDes level test sends a test frame from the ASIC through the SerDes chipand back to the ASIC for the selected ports. The port passes the test if theframe that was sent by the ASIC matches the test frame that was received.This test requires that the port be in diagnostics mode, and therefore,disrupts communication. SFP level (External) - The SFP level test verifies port circuitry. The SFPlevel test sends a test frame from the ASIC through the SerDes chip,through the SFP transceiver fitted with an external loopback plug, and backto the ASIC for the selected ports. The port passes the test if the test framethat was sent by the ASIC matches the test frame that was received. Thistest requires that the port be in diagnostics mode, and therefore, disruptscommunication.