IBM Brocade 4 Gb SAN Switch Module Installation Manual page 35

v When this LED is amber and flashing slowly, the indicated port has
been disabled, or switch beaconing is on.
v When this LED is amber and flashing rapidly, it indicates the
port-diagnostics program has detected an error (port fault).
v When this LED is not lit, it indicates that there are no faults on the
indicated port.
Chapter 3. Information panel LEDs and external Fibre Channel ports
23