OSM Service Connection User's Guide (G06.30+)

even if you are not sure a loopback test needs to be cleared on the PIC.
Enable/Disable Port
Enables or disables the port for this CRU.
Parameter: Enabled (true = enabled, false = disabled)
Note: If the port being enabled or disabled is on an NNA-type (MSEB) PIC connected to an
External Servernet Switch, you must issue a Reset on the Primary SP in Group 1.
External Loopback Test
The external loopback test checks the circuitry of a plug-in card (PIC) to determine if ServerNet
traffic can pass through the PIC. You can use this test on a PIC installed in any port of an MSEB or
IOMF2 CRU. This test requires you to remove the ServerNet cable attached to the PIC and install a
loopback plug.
The external loopback test indicates whether or not the PIC circuitry is operational or faulty. Unlike
the internal loopback test, the external loopback test also checks the connector on the PIC.
Caution: Do not use the external loopback test on a PIC that you believe is operating normally.
Doing so shuts down ServerNet traffic through the PIC for the duration of the test
(several minutes). The action isolates the MSEB port occupied by the PIC, preventing
the port from sending or receiving ServerNet traffic. ServerNet traffic resumes when
the test is finished.
Do not use the external loopback test if alarms are present on the peer fabric (the fabric
opposite the PIC you intend to test). If you do so, you might lose access to both fabrics,
thereby isolating the enclosure from the rest of the system. Multiple enclosures can be
lost in this manner.
When to Use the External Loopback Test
Typically, you use the external loopback test to isolate the cause of a malfunctioning ServerNet link
where a PIC is part of that path. Use this test if you have run the internal loopback test on a PIC, and
the test passed, but you believe the PIC might still be bad. If both PICs of a ServerNet link pass the
external test, but the link is not usable, probably the ServerNet cable is faulty.
Internal Loopback Test
Tests the circuitry of a plug-in card (PIC) installed in an MSEB to determine if ServerNet traffic can
pass through the PIC.
Caution: Do not perform this test on a PIC that is operating normally because it will shut down
ServerNet traffic through the PIC. Also, do not perform this test on an NNA-type
ServerNet PIC because the test will fail even if nothing is wrong with the NNA PIC.
Note: This test fails if no device is attached to the PIC even if nothing is wrong with the PIC
itself.