Keep the dust cap(s) on the ends of the cable and on the transceivers
of the adapter until the connections are ready to be made. This
prevents dirt and oils from soiling any important surfaces. Do not
attempt to polish the connectors with a cloth made of synthetic
fibers; this charges the fiber and attracts dust.
When connecting a fiber optic cable, do not stretch, puncture,
or crush the cable with staples or heavy equipment. Always maintain
the minimum bend radii specified by the cable manufacturer. The
fiber in fiber optic cable can suffer damage if the cable is bent
in small radii. The minimum bend radius is usually 10-20 times a
cable's outer diameter.
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 | CAUTION: Do not force the connectors when attaching the cable
— they are keyed connections and fit one way only. |
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There are two ways to connect the adapter to the FDDI network.
It can be connected directly to the adjacent stations in a dual-ring
network or to a concentrator (DAC or SAC), typically dual-homed
for additional fault tolerance. You can use either SC-to-SC duplex
cables or SC duplex-to-MIC adapter cables with MIC-to-MIC cables.
You can use an Optical Bypass Switch (OBS) between the adapter
and the dual ring. An OBS maintains continuity of the primary and
secondary ring when the station is powered down, or in the event
of an adapter failure.
Signals must be routed such that the primary Tx output from
each station is routed to the primary Rx input of its neighbors,
and the secondary Tx output is routed to the secondary Rx input
of the other neighbor, and so forth, as shown in Figure 3-5 “Dual-Ring Tx/Rx Topology”.
Dual-Attachment SC Adapter Connections |
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This section illustrates the dual-attachment SC adapter connections.
SC connectors are a duplex style connector where the two fiber
leads snap together to form a keyed connection. Make sure the Rx
and Tx leads are marked in some common scheme for your network.
For example, if the fiber lead with a blue ring routes Tx signals
from this station, follow this convention for all other stations.
If you are connecting your dual-attachment adapter directly
to the dual ring, proceed to the next section, "Connecting
Directly to the Dual Ring." Otherwise, continue to Chapter 4 “Configuring and Verifying HP EISA
and HSC FDDI/9000”
Connecting Directly to the Dual Ring |
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This adapter can be connected directly to the dual ring by
connecting the A and B ports of its neighbors. Figure 3-7 “Typical Dual Ring with DAS Adapters” illustrates a 3-node dual ring topology
with no concentrator. Note that the A port of each station is connected
to the B port of a neighbor, continuing around the network until
the ring is complete.
During normal operation of a dual ring with no faults, each
station receives and transmits all traffic on the primary ring,
while the secondary ring is idle. If a station is turned off or
disconnected from the ring, neighboring stations detect this as
a fault or discontinuity, and wrap the traffic onto the secondary
ring, thus keeping remaining stations in communication. However,
if a second fault occurs during this time, the ring could become
segmented, separating groups of stations into independent rings.
An Optical Bypass Switch (OBS) can be used to bypass a station that
is turned off or disconnected, protecting against multiple faults
on a dual ring. Figure 3-8 “Optical Bypass Switch Configuration” shows
the connection of the OBS to a dual ring.
To connect an HSC FDDI adapter to a dual ring using an OBS,
do the following:
Connect the cables from the OBS to
the appropriate Phy A and Phy B ports on the adapter.
Connect the control cable from the OBS to the adapter.
The optical bypass socket on the adapter is a 6-pin mini-DIN connection.
Connect the cables from the FDDI network to the
appropriate ports on the OBS.
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