Owner manual

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.
PIF
Physical interface (PIF) objects are the ports on these resources through which LAN connections are
made:
Ethernet ServerNet addressable controllers (E4SA SACs)
Fast Ethernet ServerNet addressable controller (FESA SACs)
Gigabit Ethernet ServerNet addressable controllers (GESA SACs)
Common Controller ServerNet addressable controllers (CCSA SACs)
Token Ring ServerNet addressable controllers (TRSA SACs)
Location in OSM Tree: System > Group > Module > CRU > SAC > PIF
Example: TRSA PIF $ZZLAN.TRSA0.0.B