IBM System Storage DS4000, Hardware Maintenance Manual

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LED On
This indicates that a GBIC is present and functioning properly.
LED Off
This indicates a fault condition. Examples of a fault condition include: a
GBIC transmitter fault, an improperly seated GBIC, an absent GBIC, or
another failed device. The port will be in the bypass state, which
precludes the port from participating in the FC-AL. This is the normal
status of operation for fibre channel hub ports in which GBICs are not
installed.
Note: FC-AL compatible nodes must perform loop initialization procedures at
power on to function properly on the loop. FC-AL nodes also perform
loop initialization or reinitialization depending on their prior state of
operation.
4.
Check the Port Bypass (amber) LEDs. See Figure 7.
LED On
If the Active (green) LED of the port is off, the port is nonoperational
and the Bypass (amber) LED for the port is on. If a properly
functioning port (the Active green LED is on) with a GBIC present also
has the Bypass LED on, either the loss of signal or poor signal integrity
has caused the port to go into the bypass state. When the port is in this
state, it cannot participate in the FC-AL.
The bypass state is also the normal status condition when no GBIC is
present in the port, a GBIC is present but not attached to a FC-AL
node, or a GBIC is attached to a cable assembly with nothing attached
at the opposite end. Replacing such a port (or removing and reinserting
the GBIC into the same port twice) is considered to be a loop
configuration change that invokes the Loop Initialization Procedure.
LED Off
This indicates that the fibre channel hub port and device are fully
operational and actively participating in the FC-AL.
5. The FC-AL should be fully operational. Check that proper loop discovery has
taken place and all required devices are participating in the loop. Some host
bus adapters might provide this level of functionality or it might be resident in
the application software on the host operating system.
Active On
Green LEDs on Top Row
Figure 6. Type 3523 fibre channel hub active LEDs
Bypass
Amber LEDs on Bottom Row
Figure 7. Type 3523 fibre channel hub port bypass LEDs
Chapter 2. Type 3523 Fibre Channel Hub and GBIC
7