24
Troubleshooting
Figure 16.
FDDI “Thru” and “Wrap A” Operation
LED
Meaning
Thru
Green when the primary path enters at A and exits at B; and the
secondary path enters at B and exits at A. (Neither MIC is in a wrap
state).
Wrap A
or
Wrap B
Green when a break has occurred in the ring. The switch is
connected to the ring by only the MIC whose Wrap LED is lit.
Wrapping can occur when:
The MIC for which Wrap is
not lit is not communicating, such as
when the cable connection to the unlit MIC is interrupted.
A dual attachment station (DAS) attached to the MIC for which
Wrap is
not lit is not functional.
Refer to figure 16, below, for an illustration of Wrap and Thru
operation.
Sig A
Sig B
Green when light signals are detected from the attached station
(A or B).
Ring Op
Green if the switch is inserted and operating in an FDDI ring and
is in either Thru or Wrap mode. (Wrap is illustrated in figure 16
below.)
Bypass
Green when the switch has power, but the attached bypass switch
is causing the FDDI ring to
bypass the Switch 2000, including when
the Switch 2000 is booting and when the FDDI circuit is disabled.
This LED is not lit when the FDDI circuit is enabled.
Net Fail
Orange when the interface fails self-test or is not operating on an
active FDDI ring. Possible causes of failure include the switch, the
FDDI Module, the cabling, the attached station, or the optical
bypass.
